Applent Instruments AT381 Series User manual

1
Contents
User’s Guide
Rev.A1
FIRMWARE REVISIONS
This manual applies directly
to instruments that have
the firmware Rev. C7
AT381x
LCR Meter
Applent Instruments Ltd
No.61-3, Baolong International,Chahua Road, Zhonglou
District ,Changzhou City, Jiangsu Province, China
[213014]
Tel: [phone] Fax: [phone]
http://www.applent.com
Sales Email: [email protected]
Tech Email: [email protected]om
©2005-2018 Applent Instruments Ltd.

Safety Summary
WARNING DANGER: When you notice any of the following abnormal conditions, terminate operation
immediately and disconnect the power cord. Contact Applent Instruments Sales for repair. Failure to do so may
result in fire or potential electrical shock to operators.
⚫Instrument is operating abnormally.
⚫Instrument produces abnormal noise, odor, smoke or flash during operation.
⚫Instrument generates high temperature or electric shock during operation.
⚫Power cord, power switch, or power outlet is damaged.
⚫Impurities or liquids flow into the instrument.
Safety Information
WARNING DANGER: To avoid possible electric shock and personal safety, follow guidelines in below.
Disclaimer
Users should read the following safety information carefully before starting
to use the instrument. Applent Instruments will not be held liable for any
personal safety and property damage caused by user's failure to comply with
the following terms.
Ground
The instrument
To avoid electric shock hazard, the instrument chassis and cabinet must be
connected to a safety earth ground by the supplied power cable with earth
blade.
DO NOT
Operate in an Explosive
Atmosphere
Do not use the instrument in a flammable or explosive atmosphere, steam or
dusty environment. The use of any electronic device in such an environment
is an adventure for personal safety.
DO NOT
Open instrument enclosure
Non-professional maintenance personnel should not open the instrument
case in an attempt to repair the instrument. The instrument still has charge
after a period of shutdown, which may pose a shock hazard to users.
Do not
Use a damaged instrument
If the instrument has been damaged, its danger will be unpredictable. Please
disconnect power cord and don’t use the instrument; do not attempt to
repair it.
Do not
Use an instrument that works
abnormally
If the instrument is not working properly, its danger is unpredictable. Please
disconnect power cord and don’t use the instrument; do not attempt to
repair it.
Do not
Use the instrument beyond
instructions specified in this
manual
If out of scope, the protection provided by the instrument will be invalid.

3
Contents
CERTIFICATION, LIMITED WARRANTY, & LIMITATION OF LIABILITY
Applent Instruments, Inc. （shortened form Applent）certifies that this product met its published specifications at
the time of shipment from the factory. Applent further certifies that its calibration measurements are traceable to
the People’s Republic of China National Institute of Standards and Technology, to the extent allowed by the
Institution’s calibration facility or by the calibration facilities of other International Standards Organization
members.
This Applent instrument product is warranted against defects in material and workmanship for a period
corresponding to the individual warranty periods of its component products. The warranty period is 1 year and
begins on the date of shipment. During the warranty period, Applent will, at its option, either repair or replace
products that prove to be defective. This warranty extends only to the original buyer or end-user customer of a
Applent authorized reseller, and does not apply to fuses, disposable batteries or to any product which, in Applent’s
opinion, has been misused, altered, neglected or damaged by accident or abnormal conditions of operation or
handling.
For warranty service or repair, this product must be returned to a service facility designated by Applent. The buyer
shall prepay shipping charges to Applent and Applent shall pay shipping charges to return the product to the Buyer.
However, the Buyer shall pay all shipping charges, duties, and taxes for products returned to Applent from another
country.
Applent warrants that its software and firmware designated by Applent for use with an instrument will execute its
programming instruction when properly installed on that instrument. Applent does not warrant that the operation
of the instrument, or software, or firmware, will be uninterrupted or error free.
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Buyer,
Buyer-supplied software or interfacing, unauthorized modification or misuse, operation outside the environmental
specifications for the product, or improper site preparation or maintenance.
THIS WARRANTY IS BUYER’S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE. APPLENT SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
OR CONSEQUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, WHETHER ARISING FROM BREACH OF
WARRANTY OR BASED ON CONTRACT, TORT, RELIANCE OR ANY OTHER THEORY.
Applent Instruments, Inc.
Changzhou,
Jiangsu,
China,
Rev.A3 October, 2009

Contents
Safety Summary ...........................................................................................................................................................................................2
Safety Information................................................................................................................................................................................... 2
CERTIFICATION, LIMITED WARRANTY, & LIMITATION OF LIABILITY.........................................................................................3
Contents........................................................................................................................................................................................................4
Figure Contents ......................................................................................................................................................................................10
Table Contents ........................................................................................................................................................................................12
1. Unpacking and Preparation ...............................................................................................................................................................13
1.1 Packing List..........................................................................................................................................................................13
1.2 Power Requirements........................................................................................................................................................13
1.3 Operating Environment ..................................................................................................................................................13
1.4 Cleaning................................................................................................................................................................................13
1.5 How to Remove the Handle..........................................................................................................................................15
2. Overview...........................................................................................................................................................................................16
2.1 Introduction ........................................................................................................................................................................16
2.2 Measurement Function...................................................................................................................................................17
2.2.1 Measurement Parameters ....................................................................................................................................17
2.2.2 Equivalent Method..................................................................................................................................................17
2.2.3 Range...........................................................................................................................................................................18
2.2.4 Test Speed..................................................................................................................................................................18
2.2.5 Trigger Mode ............................................................................................................................................................18
2.2.6 Basic Accuracy ..........................................................................................................................................................18
Measurement Display Range.....................................................................................................................................................18
2.3 Signal Source......................................................................................................................................................................19
2.3.1 Test Frequency..........................................................................................................................................................19
2.3.2 Test Signal Level.......................................................................................................................................................19
2.3.3 Constant Voltage Source Internal Resistance................................................................................................19
Test Signal Level Monitoring .....................................................................................................................................................19
2.3.4 DC bias ........................................................................................................................................................................19
2.4 Main Functions...................................................................................................................................................................20
2.4.1 Correction Function................................................................................................................................................20
2.4.2 Comparator Function (Sorting Function)........................................................................................................20
2.4.3 List Sweep ..................................................................................................................................................................20
2.4.4 File Function..............................................................................................................................................................20
2.4.5 System Settings........................................................................................................................................................21
2.4.6 Interface......................................................................................................................................................................21
3. Startup...............................................................................................................................................................................................22
3.1 Front Panel...........................................................................................................................................................................22
3.1.1 Front Panel Description.........................................................................................................................................22
3.1.2 Rear Panel...................................................................................................................................................................23
3.2 Power On..............................................................................................................................................................................23
3.2.1 Power On....................................................................................................................................................................23

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Contents
3.2.2 Warm-up Time..........................................................................................................................................................23
3.3 Connect to Device under Test (DUT)..........................................................................................................................23
4. [Meas] Page.......................................................................................................................................................................................25
4.1 <MEAS DISPLAY> Page ..................................................................................................................................................25
4.1.1 Measurement Function [FUNC]..........................................................................................................................25
4.1.2 Impedange Range [RANGE] ................................................................................................................................27
4.1.3 Test Frequency [FREQ] ...........................................................................................................................................28
4.1.4 Trigger Mode [TRIG]...............................................................................................................................................29
4.1.5 Test Signal Voltage Level [LEVEL].......................................................................................................................29
4.1.6 Measurement Speed [SPEED] .............................................................................................................................30
4.1.7 [Record] Data ............................................................................................................................................................31
4.1.8 <Meas Display> Page Information Bar ...........................................................................................................31
4.2 <BIN No. DISPLAY> Page...............................................................................................................................................32
4.2.1 [Comparator] Function ON/Off..........................................................................................................................32
4.2.2 Auxiliary Bin [AUX] ON/OFF ................................................................................................................................33
4.2.3 Information Bar of [Bin No. Display].................................................................................................................34
4.3 <BIN COUNT DISPLAY> Page.......................................................................................................................................34
4.3.1 Counter Function [COUNT]..................................................................................................................................34
4.4 <LIST SWEEP DISPLAY> Page.......................................................................................................................................35
4.4.1 Sweep Trigger Mode [TRIG].................................................................................................................................35
4.4.2 Sweep [Method] Settings.....................................................................................................................................36
4.5 <<Measure Full Screen Display> Page .....................................................................................................................36
5. [Setup] Key.......................................................................................................................................................................................37
5.1 <MEAS SETUP> Page ......................................................................................................................................................37
5.1.1 Source Output Impedance [SRC RES] ..............................................................................................................38
5.1.2 Averaging Factor [AVG] .........................................................................................................................................38
5.1.3 DC Bias Voltage........................................................................................................................................................39
5.1.4 Auto LCZ Function [AUTO LCZ] ..........................................................................................................................39
5.1.5 Monitor 1 and Monitor 2 [MON 1][MON 2] Parameter Selection.........................................................39
5.1.6 Measurement [Delay].............................................................................................................................................40
5.1.7 [Constant Level] Function.....................................................................................................................................40
5.1.8 [Nominal Value] Setting........................................................................................................................................40
5.2 <CORRECTION> Page.....................................................................................................................................................40
5.2.1 Open correction [OPEN] .......................................................................................................................................41
5.2.2 Short Correction [SHORT] ....................................................................................................................................42
5.2.3 Frequency 1, 2, 3 Correction [FREQ 1] [FREQ 2] [FREQ3]..........................................................................43
5.3 Comparator Setup ............................................................................................................................................................45
5.3.1 【Function】Setup................................................................................................................................................46
5.3.2 Comparator Function ON/OFF ...........................................................................................................................46
5.3.3 Compare【Mode】.................................................................................................................................................46
5.3.4 Nominal value for tolerance mode ...................................................................................................................48
5.3.5 [Auxiliary] Bin ON/OFF ..........................................................................................................................................48
5.3.6 【Beep】feature.......................................................................................................................................................48
5.3.7 Total Number of Bins [#-BINS] ...........................................................................................................................49
5.3.8 Lower and Upper Limits Setup ...........................................................................................................................49
5.4 <LIST SWEEP SETUP> Page...........................................................................................................................................50

5.4.1 Sweep Trigger Mode [TRIG].................................................................................................................................50
5.4.2 List Sweep Parameters Setup..............................................................................................................................51
5.4.3 Configure the sweep points ................................................................................................................................51
5.4.4 Limit parameters [CMP] selection......................................................................................................................51
5.4.5 Input [Lower] and [Upper] Limits Value...........................................................................................................52
6. System Configurations......................................................................................................................................................................53
6.1 <SYSTEM CONFIG> Page...............................................................................................................................................53
6.1.1 System Language [LANGUAGE] .........................................................................................................................53
6.1.2 Setting the system date and time .....................................................................................................................54
6.1.3 Account Setting........................................................................................................................................................54
6.1.4 Beep Tone Setting ...................................................................................................................................................55
6.1.5 RS-232 Baud Rate Setting ....................................................................................................................................55
6.1.6 [Communication Protocol] Settings..................................................................................................................55
6.1.7 【Terminator】Setting ...........................................................................................................................................56
6.1.8 [Command Handshake] ON/OFF.......................................................................................................................56
6.1.9 【Error Code】ON/OFF .........................................................................................................................................57
6.1.10 [Result Send] Setting..............................................................................................................................................57
6.1.11 [Data Cache]..............................................................................................................................................................58
6.1.12 [Factory Setting].......................................................................................................................................................58
6.2 System Information Page ...............................................................................................................................................58
7. File Operation....................................................................................................................................................................................59
7.1 <CATALOG> Page.............................................................................................................................................................59
7.1.1 [Memory] Selection ................................................................................................................................................59
7.1.2 Recall a File at Startup [AUTO RECALL] ...........................................................................................................60
7.1.3 Auto save data to last file [AUTO SAVE]..........................................................................................................60
7.1.4 File operation............................................................................................................................................................60
8. PLC（Handler）Interface.................................................................................................................................................................61
8.1 Pin Assignment..................................................................................................................................................................61
8.2 How to Connection ..........................................................................................................................................................62
8.3 Timing Chart .......................................................................................................................................................................63
9. Remote Control.................................................................................................................................................................................65
9.1 About RS-232C ..................................................................................................................................................................65
9.1.1 RS232C Connection................................................................................................................................................65
9.1.2 How to Connect.......................................................................................................................................................66
9.2 Protocol ................................................................................................................................................................................66
9.3 SCPI Protocol：..................................................................................................................................................................66
9.3.1 Modbus(RTU) Protocol..........................................................................................................................................67
10. SCPI Command Reference.......................................................................................................................................................68
10.1 Handshake Protocol.........................................................................................................................................................68
10.2 Terminator............................................................................................................................................................................68
10.3 Terminator............................................................................................................................................................................69
10.3.1 Terminator Rules......................................................................................................................................................69
10.3.2 Notation Conventions and Definitions............................................................................................................69
10.3.3 Command Structure ...............................................................................................................................................70
10.4 Header and Parameters ..................................................................................................................................................70
10.4.1 Header.........................................................................................................................................................................70
10.4.2 Parameter...................................................................................................................................................................70

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Contents
10.4.3 Separator....................................................................................................................................................................71
10.4.4 Error Code..................................................................................................................................................................71
10.5 Command Reference .......................................................................................................................................................72
10.6 DISPlay Subsystem ...........................................................................................................................................................72
10.6.1 DISP:PAGE...................................................................................................................................................................73
10.6.2 DISP:LINE....................................................................................................................................................................73
10.7 FUNCtion Subsystem.......................................................................................................................................................74
10.7.1 FUNCtion....................................................................................................................................................................74
10.7.2 FUNCtion:IMPedance:AUTO ................................................................................................................................74
10.7.3 FUNCtion:IMPedance:RANGe .............................................................................................................................75
10.7.4 FUNCtion:DCR:RANGe...........................................................................................................................................75
10.7.5 FUNCtion:RANGe:AUTO........................................................................................................................................75
10.7.6 FUNCtion:MONitor1 /2 .........................................................................................................................................75
10.8 FREQuency Subsystem....................................................................................................................................................76
10.9 LEVel Subsystem................................................................................................................................................................76
10.9.1 LEVel:VOLTage (=VOLTage[:LEVel])....................................................................................................................77
10.9.2 LEVel:CURRent (=CURRent[:LEVel]) ...................................................................................................................77
10.9.3 LEVel:SRESistance (= VOLTage:SRESistance)..................................................................................................77
10.9.4 LEVel:ALC (=AMPlitude:ALC)................................................................................................................................78
10.10 APERture Subsystem........................................................................................................................................................78
10.10.1 APERture:RATE?........................................................................................................................................................78
10.10.2 APERture:AVG? .........................................................................................................................................................79
10.11 FETCh Subsystem ..............................................................................................................................................................79
10.11.1 FETCh? .........................................................................................................................................................................79
10.11.2 FETCh:IMPedance? ..................................................................................................................................................79
10.11.3 FETCh:MAIN?.............................................................................................................................................................79
10.11.4 FETCh:MONitor1? /2?.............................................................................................................................................80
10.11.5 FETCh:MONitor?.......................................................................................................................................................80
10.12 COMParator Subsystem..................................................................................................................................................80
10.12.1 COMParator:STATe ..................................................................................................................................................81
10.12.2 COMParator:MODE.................................................................................................................................................81
10.12.3 COMParator:AUX.....................................................................................................................................................82
10.12.4 COMParator:BINS....................................................................................................................................................82
10.12.5 COMParator:TOLerance:NOMinal......................................................................................................................82
10.12.6 COMParator:TOLerance:BIN ................................................................................................................................82
10.12.7 COMParator:SLIM....................................................................................................................................................83
10.12.8 COMParator:BEEP....................................................................................................................................................83
10.12.9 COMParator:OPEN..................................................................................................................................................83
10.13 LIST Subsystem ..................................................................................................................................................................84
10.13.1 LIST:PARAmeter........................................................................................................................................................84
10.13.2 LIST:STAT.....................................................................................................................................................................84
10.13.3 LIST:BAND ..................................................................................................................................................................84
10.14 CORRection Subsystem...................................................................................................................................................85
10.14.1 CORRection:OPEN...................................................................................................................................................86
10.14.2 CORRection:SHORt .................................................................................................................................................87

10.14.3 CORRection:SPOT:FREQuency.............................................................................................................................87
10.14.4 CORRection:SPOT:OPEN........................................................................................................................................87
10.14.5 CORRection:SPOT:SHORt......................................................................................................................................87
10.15 TRIGger Subsystem ..........................................................................................................................................................88
10.15.1 TRIGger[:IMMediate]..............................................................................................................................................88
10.15.2 TRIGger:SOURce......................................................................................................................................................88
10.15.3 TRIGger:DELAY .........................................................................................................................................................88
10.16 BIAS Subsystem .................................................................................................................................................................89
10.17 FILE Subsystem...................................................................................................................................................................89
10.17.1 FILE?..............................................................................................................................................................................89
10.17.2 FILE:SAVE ....................................................................................................................................................................89
10.17.3 FILE:LOAD...................................................................................................................................................................90
10.17.4 FILE:DELete.................................................................................................................................................................90
10.18 ERRor Subsystem...............................................................................................................................................................90
10.18.1 ERRor?..........................................................................................................................................................................90
10.19 SYSTEM Subsystem ..........................................................................................................................................................90
10.19.1 SYSTem:SHAKehand ...............................................................................................................................................90
10.19.2 SYSTem:CODE ...........................................................................................................................................................91
10.19.3 SYSTem:KEYLock ......................................................................................................................................................91
10.19.4 SYSTem:RESult ..........................................................................................................................................................91
10.20 Common Commands.......................................................................................................................................................91
10.20.1 *IDN?............................................................................................................................................................................91
10.20.2 *TRG .............................................................................................................................................................................91
10.20.3 *SAV..............................................................................................................................................................................92
10.20.4 *RCL..............................................................................................................................................................................92
11. Modbus（RTU）Protocol .......................................................................................................................................................93
11.1 Data Format ........................................................................................................................................................................93
11.1.1 Command Frame.....................................................................................................................................................93
11.1.2 CRC-16 Calculation Method................................................................................................................................94
11.1.3 Response Frame.......................................................................................................................................................95
11.1.4 No Response.............................................................................................................................................................95
11.1.5 Error Code..................................................................................................................................................................96
11.2 Function Code....................................................................................................................................................................96
11.3 Register.................................................................................................................................................................................96
11.4 Read Multiple Registers..................................................................................................................................................96
11.5 Writing to Multiple Registers........................................................................................................................................97
11.6 Echo Test...............................................................................................................................................................................98
12. Modbus（RTU）Command ..................................................................................................................................................100
12.1 Register Overview...........................................................................................................................................................100
12.2 Obtain Measurement Data ..........................................................................................................................................104
12.2.1 Obtain measurement data.................................................................................................................................104
12.2.2 Obtain Comparator Results 【2004】...........................................................................................................105
12.3 Parameter Setting ...........................................................................................................................................................106
12.3.1 Function Register【3000】.................................................................................................................................106
12.3.2 LCR Range Register【3001】.............................................................................................................................107

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Contents
12.3.3 Range Mode Register【3002】........................................................................................................................107
12.3.4 Test Speed Register【3003】............................................................................................................................108
12.3.5 Average Times Register【3004】.....................................................................................................................109
12.3.6 Trigger Mode Register【3005】.......................................................................................................................109
12.3.7 Test Frequency Register【3006】【 3007】....................................................................................................110
12.3.8 Test Voltage Register【3008】【 3009】..........................................................................................................110
12.3.9 DCR Range Register【300A】...........................................................................................................................111
12.3.10 Startup File Recall Register【300C】..............................................................................................................112
12.3.11 Auto Save【300D】..............................................................................................................................................112
12.3.12 System Language Setting【300E】.................................................................................................................113
12.3.13 Test Current Register【3010】【 3011】..........................................................................................................113
12.3.14 DC Bias Register【3012】【 3013】...................................................................................................................114
12.4 Comparator Setting........................................................................................................................................................115
12.4.1 Comparator Status Register【3100】.............................................................................................................115
12.4.2 Comparator Mode Register【3101】.............................................................................................................115
12.4.3 Secondary Comparator ON/OFF Register【3102】..................................................................................116
12.4.4 Comparison Bin No. Register【3103】..........................................................................................................117
12.4.5 Alarm Register【3104】......................................................................................................................................117
12.4.6 Nominal Value Register【310A】【 310B】....................................................................................................118
12.4.7 Secondary Parameter Limit Value Register【310C-310F】.....................................................................118
12.4.8 Primary Parameter Limit Value Register【3110-3133】..........................................................................119
12.5 File Operation...................................................................................................................................................................119
12.5.1 Save to Current File【4000】............................................................................................................................120
12.5.2 Save to Specified File【4008】.........................................................................................................................120
12.5.3 Reloading the Current File【4010】...............................................................................................................120
12.5.4 Load the Specified File【4018】......................................................................................................................121
12.6 Correction ..........................................................................................................................................................................121
12.6.1 Full-frequency Open Circuit Correction【5000】......................................................................................121
12.6.2 Full-frequency Short-circuit Correction【5008】.......................................................................................122
12.6.3 Point frequency Correction Setting【5010~5015】..................................................................................123
12.6.4 Point Frequency Open Circuit Correction【5020】...................................................................................123
12.6.5 Point Frequency Short Circuit Correction【5028】...................................................................................124
12.7 System Setup....................................................................................................................................................................125
12.7.1 Instrument version number【0000】.............................................................................................................125
13. Performace Test......................................................................................................................................................................126
13.1 Accuracy .............................................................................................................................................................................126
13.1.1 Accuracy for L, C, R, |Z| ........................................................................................................................................126
13.1.2 D Accuracy...............................................................................................................................................................126
13.1.3 Q Accuracy...............................................................................................................................................................126
13.1.4 Accuracy................................................................................................................................................................127
13.1.5 RpAccuracy..............................................................................................................................................................127
13.1.6 RsAccuracy ..............................................................................................................................................................127
13.2 Accuracy Factor................................................................................................................................................................127
13.3 Performace Test ...............................................................................................................................................................130
13.3.1 Devices and Equipment Used for Performance Test.................................................................................130
13.3.2 Function check .......................................................................................................................................................131

13.3.3 Test signal level accuracy test ...........................................................................................................................131
13.3.4 Frequency accuracy test......................................................................................................................................131
13.3.5 Capacitance C, loss D accuracy test................................................................................................................131
13.3.6 Inductance L accuracy test.................................................................................................................................131
13.3.7 Impedance Z accuracy test ................................................................................................................................131
14. Examples................................................................................................................................................................................133
14.1 Basic Measurement Procedure...................................................................................................................................133
14.2 Example ..............................................................................................................................................................................134
15. Specification ..........................................................................................................................................................................136
15.1 Technical Indicators........................................................................................................................................................136
15.2 General Specification.....................................................................................................................................................136
15.3 Dimensions........................................................................................................................................................................138
Figure Contents
Figure 1-1 Instrument handle (schematic, panel graphics do not match the actual)...........................................15
Figure 3-1 front panel .................................................................................................................................................................22
Figure 3-2 rear panel ...................................................................................................................................................................23
Figure 3-3 Connect to DUT........................................................................................................................................................23
Figure 4-1 <MEAS DISPLAY> Page.........................................................................................................................................25
Figure 4-2 <BIN No. DISPLAY> page.....................................................................................................................................32
Figure 4-3 Comparator Workflow...........................................................................................................................................32
Figure 4-4 <BIN COUNT DISPLAY > page ...........................................................................................................................34
Figure 4-5 <LIST SWEEP DISPLAY> page.............................................................................................................................35
Figure 4-6 Sweep Mode .............................................................................................................................................................35
Figure 4-7 <Measure Full Screen Display> Page...............................................................................................................36
Figure 5-1 <MEAS SETUP> Page.............................................................................................................................................37
Figure 5-2 <CORRECTION> Page ...........................................................................................................................................41
Figure 5-3 Stray Admittance .....................................................................................................................................................41
Figure 5-4 Residual Impedances .............................................................................................................................................42
Figure 5-5 < COMP Setup > page..........................................................................................................................................45
Figure 5-6 Tolerance mode........................................................................................................................................................46
Figrue 5-7 Example of sorting in tolerance mode.........................................................................................................................47
Figure 5-8 sequential mode:.....................................................................................................................................................47
Fiture 5-9 <LIST SWEEP SETUP> Page .................................................................................................................................50
Figure 5-10 Sweep Mode .............................................................................................................................................................50
Figure 6-1 <SYSTEM CONFIG> Page.....................................................................................................................................53
Figure 6-2 < System Information> page..............................................................................................................................58
Figure 7-1 <CATALOG> Page ...................................................................................................................................................59
Figure 8-1 Pin Assignment ........................................................................................................................................................61
Figure 8-2 Typical Circuit Diagram of Handler Interface Input signals（Trig）......................................................62
Figure 8-3 Typical Circuit Diagram of Handler Interface Output signals（sorting，IDX，EOM）..................63
Figure 8-4 Signal timing chart..................................................................................................................................................63
Figure 9-1 RS-232 interface on the rear panel [male] .....................................................................................................65
Figure 9-2 RS-232 interface on the rear panel [male] .....................................................................................................66

11
Contents
Figure 10-1 Command Tree Structure......................................................................................................................................70
Figure 11-1 Modbus Command Frame ...................................................................................................................................93
Figure 11-2 Modbus append CRC-16 value...........................................................................................................................94
Fiture 11-3 Normal response frame ........................................................................................................................................95
Figure 11-4 Abnormal response frame....................................................................................................................................95
Figure 11-5 Read Multiple Registers（0x03）.......................................................................................................................96
Figure 11-6 Read Multiple Registers（0x03）Response Frame......................................................................................97
Figure 11-7 Writing to multiple registers（0x10）..............................................................................................................97
Figure 11-8 Write to Multiple Registers（0x03）Response Frame................................................................................98
Figure 11-9 echo test（0x08）...................................................................................................................................................98
Figure 13-1 Basic measurement accuracy A....................................................................................................................................127
Figure 13-2 Basic accuracy correction curve...................................................................................................................................128
Figure 14-1 Measurement flow chart.....................................................................................................................................133
Figure 14-2 Capacitor test results............................................................................................................................................135

Table Contents
Table 2-1 Series-parallel equivalent circuit....................................................................................................................17
Table 2-2 AT381x Measurement display range ................................................................................................................18
Table 2-3 Test signal accuracy ................................................................................................................................................19
Table 3-1 Front Panel Description.........................................................................................................................................22
Table 4-1 The combinations of measurement parameters......................................................................................26
Table 4-2 The combinations of monitor parameters .................................................................................................26
Table 4-3 Measurement and Monitor parameter descriptions...................................................................................26
Table 4-4 Impedance range mode........................................................................................................................................27
Table 4-5 Range and corresponding test range ..............................................................................................................27
Table 4-6 AT381x frequency resolution...............................................................................................................................28
Table 4-7 AT3818 the most commonly used frequency list.........................................................................................28
Table 4-8 AT3816A/AT3816B List of the most common frequencies.......................................................................28
Table 4-9 AT3817A Frequency list.........................................................................................................................................28
Table 4-10 AT3810A List of the most common frequencies ..........................................................................................29
Table 4-11 The most commonly used level list ..................................................................................................................30
Table 4-12 Sweep trigger mode...............................................................................................................................................35
Table 4-13 sweep method..........................................................................................................................................................36
Table 5-1 Sweep trigger mode description .......................................................................................................................50
Table 6-1 SCPI error code ........................................................................................................................................................57
Table 8-1 Description of Handler Interface Output Signals.........................................................................................61
Table 8-2 Description of Handler Interface Input Signals ............................................................................................62
Table 8-3 Description of Handler Interface Power Rating Signals.............................................................................62
Table 8-4 Timing..........................................................................................................................................................................63
Table 9-1 The minimum subset of the RS-232 standard ..............................................................................................65
Table 10-1 Multiplier Mnemonics............................................................................................................................................71
Table 10-2 SCPI error code ........................................................................................................................................................71
Table 11-1 Command Frame Description.............................................................................................................................93
Table 11-2 Description for abnormal response frame .....................................................................................................95
Table 11-3 Description for Error Code ...................................................................................................................................96
Table 11-4 Function code...........................................................................................................................................................96
Table 11-5 Read Multiple Registers ........................................................................................................................................97
Table 11-6 Writing to multiple registers ...............................................................................................................................97
Table 12-1 Register Overview .................................................................................................................................................100
Table 13-1 Impedance scale factor Ka, Kb ...............................................................................................................................129
Table 13-2 Temperature factor Kc..........................................................................................................................................129
Table 13-3 Calibration interpolation factor Kf...................................................................................................................130
Table 13-4 Cable length factor ...............................................................................................................................................130
Table 13-5 Devices and equipment used for performance testing...........................................................................130

13
Unpacking and Preparation
1. Unpacking and Preparation
Thank you for purchasing our products. Please read this chapter carefully before use.
In this chapter you will learn the following:
⚫Packing List
⚫Power Requirements
⚫Operating Environment
⚫Cleaning
⚫How to Remove the Handle
1.1 Packing List
Before using the instrument, please:
1. Check appearance of the product whether there is damage, scratches, etc.;
2. Check the instrument packing list if there are any missing items.
If there is any damage or insufficient accessories, please contact Applent Instruments Sales or
distributor immediately.
1.2 Power Requirements
AT381x can only be used in the following power conditions:
Voltage: 90V-260VAC
Power: up to 30VA
Warning: To prevent electric shock, please connect the power ground.
If users replace power cord, make sure that the ground of the power cord is securely
connected.
1.3 Operating Environment
AT381x must be used under the following environmental conditions:
Temperature: 0C～55C,
Humidity: < 70% RH at 23℃
1.4 Cleaning
To prevent the risk of electric shock, unplug the power cord before cleaning.
To prevent electrical shock, disconnect the AT381x power cable from the receptacle before
cleaning.
Use a dry cloth or a cloth slightly dipped in water to clean the casing. Do not attempt to clean

the AT381x internally.
WARNING: Don’t Use Organic Solvents (such as alcohol or gasoline) to clean the
instrument.

15
Unpacking and Preparation
1.5 How to Remove the Handle
Instrument handle can be adjusted. Hold both sides of the handle with both hands, gently pull
it to the sides, then rotate the handle. The handle can be adjusted to four positions as shown
below:
Figure 1-1 Instrument handle (schematic, panel graphics do not match the actual)
Visible position 1 [Hands hold both sides of the handle at the same
time, gently pull it to the sides until it can rotate freely, then switch
to the visible position 2]
Handheld position
Visible position 2 [hold both sides of the handle at the same time,
gently pull it to the sides until it can rotate freely, then switch to the
handheld position]

Remove handle position. (Pull to both sides until the handle is removed.)
2. Overview
This chapter contains general information about AT381x. The information is organized as
follows
⚫Introduction
⚫Measurement Function
⚫Signal Source
⚫Main Functions
2.1 Introduction
Thank you for purchasing AT381X LCR meter.
AT381X is precision LCR meter that uses a fully automated real-time inspection micro-desktop
instrument controlled by high-performance 32-bit ARM microprocessor. The instrument can
select any test frequency between 10Hz and 300kHz, and can select test signal level between
0.01V and 2.00V with 0.01V steps. Built-in -2.5V~+2.5V programmable DC bias automatically
measures inductance L, capacitance C, resistance value R, complex impedance Z, quality factor
Q, loss tangent value D, phase angle (degrees), phase (radian), and DC resistance DCR.
The primary and secondary parameters are displayed in all 6 digits, there are two monitoring
displays at the same time. One of Z, D, Q, r, d, R, X, G, B, Y, Vac, Iac, , % can be displayed at
the same time. With an accuracy of up to 0.05%, the instrument can meet requirements of
accurate testing and mass production by various component manufacturers, schools, research
institutes and metrological quality inspection departments.
The instrument has a professional sorting function, with 10 sets of storage files,

17
Overview
programmable 9 qualified file, 1 auxiliary file (secondary-parameter unqualified), 1
unqualified file and primary parameter HI/IN/LO file, can set percentage points or absolute
value sorting, equipped with Handler interface and RS-232C interface, used in automatic
sorting system to complete automatic pipeline testing. An optional USB memory interface
allows users to save setup data and measurement data to an external mover.
The instrument supports two kinds of communication protocols: computer remote control
instruction is compatible with SCPI (Standard Command for Programmable Instrument
standard command set) and Modbus communication protocol, remote control and data
acquisition functions are efficiently completed.
Reference：
See 11. Specifications section for complete technical specifications.
2.2 Measurement Function
2.2.1 Measurement Parameters
Measurement parameters：Cs-Rs, Cs-D, Cp-Rp, Cp-D, Lp-Rp, Lp-Q, Ls-Rs, Ls-Q, G-B, R-X, Z-r,
Z-d和DCR。
Among them：
L: Inductance C: Capacitance R: Resistance Z: Impedance X: Reactance
B: Density G: Conductance D: Loss : Phase angle Q: Quality factor
DCR：DC resistance
The subscript s indicates serial equivalent, p indicates parallel equivalent
2.2.2 Equivalent Method
Series, Parallel.
The actual capacitance, inductance, and resistance are not ideal for pure reactance and purely
resistive components. They usually have both resistance and reactance components. An
actual impedance component can be modeled in series or parallel by an ideal resistor and an
ideal reactor (inductor or capacitor).
It can be mathematically converted using a formula, but the two forms are different,
inconsistency depends on the quality factor Q (or loss D).
Table 2-1 Series-parallel equivalent circuit
Circuit Form
Loss D
Equivalent Conversion
L
Lp
Rp
D=2FLp/Rp=1/Q
Ls=Lp/(1+D2)
Rs=RpD2/(1+D2)
D=Rs/2FLs=1/Q
Lp=(1+D2)Ls
Rp=(1+D2)Rs/D2

C
Cp
Rp
D=1/2FCpRp=1/Q
Cs=(1+D2)Cp
Rs=RpD2/(1+D2)
Cs Rs
D=2FCsRs=1/Q
Cp=Cs/(1+D2)
Rp=Rs(1+D2)/D2
Definition for Q、D、Xs is：Q=Xs/Rs，D=Rs/Xs，Xs=1/2πFCs=2πFLs
Suggestion：
Generally, a series equivalent circuit is used for components having a low impedance
value Z (for example, a high value capacitor and a low value inductor); a parallel
equivalent circuit is used for a component having a large impedance value Z (low value
capacitor and high value inductor).
At the same time, equivalent circuit must be determined according to the actual use of
component, such as capacitors, series equivalent circuit is used for power supply filtering,
parallel equivalent circuit is used for LC oscillation circuits.
2.2.3 Range
Use 9-range test, auto, lock and nominal.
Nominal range (Applent new term definition): The instrument automatically selects the best
range based on nominal value.
2.2.4 Test Speed
The instrument is divided into four speeds: slow speed, medium speed 1, medium speed 2
and fast speed.
Fast speed: 40 times / sec
Medium speed: 10 times / sec
Slow speed: 3 times / sec
At the same time, 1-256 programmable average times can be performed to improve reading
stability.
2.2.5 Trigger Mode
Internal, external, manual, and remote trigger.
2.2.6 Basic Accuracy
AT3818 0.05%
AT3816A 0.05%
AT3816B 0.1%
AT3817A 0.05%
AT3810A 0.05%
AT3817D 0.1%
Measurement Display Range
Table 2-2 AT381x Measurement display range

19
Overview
Parameter
Measurement display range
L
0.00001nH ～9999.99H
C
0.00001pF ～9999.99mF
R、X、Z
0.00001Ω～99.9999M
B、G
0.01nS ～999.999S
D
0.00001 ～9.99999
Q
0.00001 ～99999.9
θd
-179.999°～179.999°
θr
-3.14159 ～3.14159
%
-999.999% ～999.999%
2.3 Signal Source
2.3.1 Test Frequency
AT3818：10Hz～300kHz continuous test frequency
AT3816A：50Hz～200kHz continuous test frequency
AT3816B：50Hz～200kHz 37 points
AT3817A: 50Hz～100kHz continuous test frequency
AT3810A: 10Hz～20kHz continuous test frequency
AT3817D: 50Hz～100kHz, 10 points
Frequency accuracy：0.01%
2.3.2 Test Signal Level
ACV：10.00mV~2.00V, Accuracy：10%，CV mode accuracy：6%
ACI：100.0μA~20.00mA，Accuracy：10%，CC mode accuracy：6% @2Vmax
DCR：±1VDC（2Vpp）square wave，3Hz Maximum
0.033A（Max）， output impedance 30Ω
2.3.3 Constant Voltage Source Internal Resistance
Can be set to 30、50and 100
Test Signal Level Monitoring
Table 2-3 Test signal accuracy
2.3.4 DC bias
-2.5V~+2.5V
Accuracy：0.5%（±0.005V）
Mode
Range
Accuracy
Voltage
10mVRMS - 2.00VRMS
0.01mVRMS - 10mVRMS
±（3%×reading+0.5mV）
±（12%×reading+0.1mV）
Current
100μARMS - 66mARMS
0.001μARMS - 100μARMS
±（3%×reading+5μA）
±（12%×reading+1μA）

2.4 Main Functions
2.4.1 Correction Function
Open clear zero: Eliminate effects of stray impedance on the test side and the instrument.
The instrument can perform single-point, three-point frequency open circuit clear zero or
sweep frequency (all typical frequency) open circuit clear zero.
Short-circuit clear zero: Eliminate effects of series resistance and inductance of the leads.
The instrument can perform single point, thre-point frequency short circuit clear zero or
sweep frequency (all typical frequency) short circuit clear zero.
2.4.2 Comparator Function (Sorting Function)
The instrument can perform multiple sorting, sorting is based on the measured values,
regardless of deviation mode.
PASS file (BIN1-BIN9): indicates that both of primary and secondary parameters are qualified;
Auxiliary file (AUX): indicates that primary parameter is qualified but secondary parameter is
unqualified when the auxiliary file is opened;
FAIL (OUT): The primary parameter is unqualified, or the primary parameter is qualified but
the secondary parameter is unqualified when the auxiliary file is closed.
HI/IN/LO: More detailed comparison results of primary parameters, HI: primary parameters
are high, LO: primary parameters are low, IN: primary parameters are qualified
•Comparison Method:
Absolute tolerance ±TOL sorting: The absolute deviation of measured value from nominal
value is compared with the limit of each bin.
Percentage tolerance TOL sorting: The percentage deviation of measured value from
nominal value is compared to the limit of each bin.
Sequential comparison sorting: The measured value is directly compared with the upper and
lower limits
•Bin count:
Each bin corresponds to a bin counter, the counting range: 0～999999。
•Bin display：
There is a bin display page and a bin count display page.
All comparator results have corresponding IO port outputs on the Handler interface.
2.4.3 List Sweep
List sweep can be performed up to 10 points frequency or 10 points voltage.
List sweep comparator: Each list sweep point can output HI/IN/LO (high/pass/low)
discrimination.
The list sweep limit sets are the upper and lower limit values.
2.4.4 File Function
There are 10 files in the instrument's internal flash memory that users can use to save
instrument data. These data include:
1. All parameters in <Settings> page
2. Setting data in <Comparator Setting> page