Applent Instruments AT520 User manual


@Instruments
Address: Lanlin Dangnan Industrial Park,
Changzhou, Jiangsu, China (PRC)
Post Code: 213014
Telephone (Sales):
0086-0519-88805550 / 89966117/89966227
Fax: [phone]
Sales Email: [email protected]
Tech Email: [email protected]
http://www.applent.com
http://www.applent.en.alibaba.com
©2005-2012 Applent Instruments LLC.
Rev. C2
[AT520/AT520SE/AT520L/AT520M ACMilliohmMeter]
USER'SGUIDE

AT520/AT520SE/AT520L/AT520M User’s Guide
2
SafetySummary
Warning Dangerous：
When you notice any of the unusual conditions listed below, immediately terminate operation and disconnect the
power cable.
Please Contact Applent Instruments Incorporation sales representative for repair of the instrument. If you continue
to operate without repairing the instrument, there is a potential fire or shock hazard for operators.
Instrument operates abnormally.
Instrument emits abnormal noise, smell, smoke, or a spark-like light during the operation.
Instrument generates high temperature or electrical shock during operation.
Power cable, plug, or receptacle on instrument is damaged.
Foreign substance or liquid has fallen into the instrument.

SafetySummary
Warning Dangerous： 
The following general safety precautions must be observed during all phases of operation, service, and repair of
this instrument. Failure to comply with these precautions or with specific WARNINGS elsewhere in this manual
may impair the protection provided by the equipment. In addition it violates safety standards of design,
manufacture, and intended use of the instrument.
Disclaimer The Applent Instruments assumes no liability for the customer's failure to
comply with these requirements.
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 operate the instrument in the presence of inflammable gasses or
fumes. Operation of any electrical instrument in such an environment
constitutes a definite safety hazard.
Keep Away
From Live
Circuits
Operating personnel must not remove instrument covers. Component
replacement and internal adjustments must be made by qualified
maintenance personnel. Do not replace components with the power cable
connected. Under certain conditions, dangerous voltages may exist even
with the power cable removed. To avoid injuries, always disconnect power
and discharge circuits before touching them.
DO NOT
Service Or Adjust Alone
Do not attempt internal service or adjustment unless another person,
capable of rendering first aid and resuscitation, is present.
DO NOT
Substitute Parts Or
Modify Instrument
Because of the danger of introducing additional hazards, do not install
substitute parts or perform unauthorized modifications to the instrument.
Return the instrument to an Applent Instruments Sales and Service Office
for service and repair to ensure that safety features are maintained.

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 2 years 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,
The People’s Republic of China.
Rev.A2 January, 2005
Rev.B0 January, 2008

Contents
Safety Summary ........................................................................................................................................................ 2
Safety Summary ........................................................................................................................................................ 3
CERTIFICATION, LIMITED WARRANTY, & LIMITATION OF LIABILITY ..................................................... 4
Contents..................................................................................................................................................................... 5
Figure Contents.......................................................................................................................................................... 7
Table Contents ........................................................................................................................................................... 7
1.Unpacking and Preparation................................................................................................................................ 8
1.1Incoming Inspection .......................................................................................................................... 8
1.2Setting up Fuse .................................................................................................................................. 8
1.3Environmental Requirements ............................................................................................................ 9
1.4Cleaning............................................................................................................................................. 9
1.5How to Remove the Handle............................................................................................................... 9
2.Overview ..........................................................................................................................................................11
2.1Introduction.......................................................................................................................................11
2.2Functional Comparison.....................................................................................................................11
2.3Main Specifications and Features .....................................................................................................11
3.Start up............................................................................................................................................................. 13
3.1Front panel....................................................................................................................................... 13
3.2Real panel ........................................................................................................................................ 14
3.3Keypad I .......................................................................................................................................... 14
3.4VFD ................................................................................................................................................. 15
3.5Power On/Off................................................................................................................................... 16
3.5.1Warm-up Time ......................................................................................................................... 16
4.Configuration................................................................................................................................................... 17
4.1Connect to Device under Test (DUT) .............................................................................................. 17
4.2Setting the Measurement Range ...................................................................................................... 17
4.3Setting the Sampling Rate................................................................................................................ 18
4.4Short Clear Zero Correction ............................................................................................................ 18
4.5Choose Measure Parameter（AT 5 2 0 ）........................................................................................... 18
4.6Relative value .................................................................................................................................. 19
4.7Voltage Limiter ................................................................................................................................ 19
4.8Set beep ON/OFF ............................................................................................................................ 19
4.9Deviation Display Mode.................................................................................................................. 19
4.10Lock out the keypad......................................................................................................................... 20
5.Comparator ...................................................................................................................................................... 21
5.1Turn ON/OFF the Comparator......................................................................................................... 21
5.2Setup the record number and comparator ........................................................................................ 21
5.3Setup Beeper.................................................................................................................................... 21
5.4How the comparator work ............................................................................................................... 22
6.Handler Interface (AT520)............................................................................................................................... 23
6.1Pin Assignment ................................................................................................................................ 23
6.2Connection method.......................................................................................................................... 24
6.3Power Rating ................................................................................................................................... 24
6.4Electrical Characteristics ................................................................................................................. 25
6.4.1Input Signal:............................................................................................................................. 25
6.4.2Output Signal:.......................................................................................................................... 25
6.4.3Power supply ........................................................................................................................... 25
6.5Timing Chart.................................................................................................................................... 25
7.Remote Control................................................................................................................................................ 27
7.1About RS-232C ............................................................................................................................... 27
7.2Enable RS-232C Interface and select baud rate............................................................................... 27
7.3SCPI Language ................................................................................................................................ 28
8.Command Reference ....................................................................................................................................... 29
8.1Terminator........................................................................................................................................ 29
8.2Notation Conventions and Definitions............................................................................................. 29
8.3Command Structure ......................................................................................................................... 29
8.4Header and Parameters .................................................................................................................... 31

AT520/AT520SE/AT520L/AT520M User’s Guide
6
8.5Command Reference ....................................................................................................................... 31
8.6FUNCtion Subsystem ...................................................................................................................... 32
8.6.1:RANGe:AUTO ....................................................................................................................... 32
8.6.2:RANGe ................................................................................................................................... 33
8.6.3:RATE ...................................................................................................................................... 33
8.6.4:DEV........................................................................................................................................ 33
8.6.5:CURRentmode........................................................................................................................ 33
8.7TRIG Subsystem.............................................................................................................................. 34
8.7.1:SOURce .................................................................................................................................. 34
8.8BEEPer Subsystem .......................................................................................................................... 34
8.8.1:BINmode ................................................................................................................................ 35
8.9FETCh Subsystem ........................................................................................................................... 35
8.10ERRor Subsystem............................................................................................................................ 36
8.11*IDN? Common Command ............................................................................................................. 36
8.12*RST Common Command............................................................................................................... 36
8.13*TRG Common Command.............................................................................................................. 36
9.Specification .................................................................................................................................................... 38
9.1AT520 Specification ........................................................................................................................ 38
9.2AT520SE Specification.................................................................................................................... 38
9.3AT520L Specification ...................................................................................................................... 39
9.4AT520M Specification..................................................................................................................... 39
9.5General Specification....................................................................................................................... 40
9.6Dimensions ...................................................................................................................................... 40

Contents 7
FigureContents
Figure 1-1 Fuse Holder................................................................................................................................ 8
Figure 1-2 How to remove the handle ....................................................................................................... 10
Figure 3-1Front panel ............................................................................................................................... 13
Figure 3-2Real panel ................................................................................................................................ 14
Figure 3-3Keypad I................................................................................................................................... 14
Figure 3-4Keypad II ............................................................................................................................... 15
Figure 3-5VFD ......................................................................................................................................... 15
Figure 4-1Connect to DUT....................................................................................................................... 17
Figure 6-1How to insert the cables........................................................................................................... 24
Figure 6-2Typical Circuit Diagram of Handler Interface Input signals.................................................... 25
Figure 6-3Typical Circuit Diagram of Handler Interface Output signals. ................................................ 25
Figure 6-4Timing chart............................................................................................................................. 25
Figure 7-1The RS-232 connector in the real panel................................................................................... 27
Figure 8-1Command Tree Example ......................................................................................................... 29
Figure 8-2FUNCtion Command Tree....................................................................................................... 32
Figure 8-3TRIG Subsystem Tree.............................................................................................................. 34
Figure 8-4BEEPer Subsystem Tree .......................................................................................................... 34
Figure 8-5FETCh? Subsystem Tree ......................................................................................................... 35
Figure 8-6ERRor Subsystem Tree............................................................................................................ 36
Figure 8-7IDN? Common Command Tree............................................................................................... 36
Figure 8-8*RST Common Command Tree............................................................................................... 36
Figure 8-9*TRG Subsystem Tree ............................................................................................................. 36
TableContents
Table 3-1Front panel description ............................................................................................................ 13
Table 3-2Real panel description.............................................................................................................. 14
Table 3-3Keypad I description................................................................................................................ 14
Table 3-4Keypad II description............................................................................................................... 15
Table 3-5VFD description....................................................................................................................... 15
Table 4-1Range number, range resistance and range change process (AT520) ...................................... 17
Table 5-1Comparator Output (Resistance/Voltage measurement mode) ................................................ 22
Table 5-2Comparator setting example: ................................................................................................... 22
Table 6-1Pin assignment ......................................................................................................................... 23
Table 6-2Description of Handler Interface Input Signals ....................................................................... 23
Table 6-3Comparator Record Selection Truth Table............................................................................... 23
Table 6-4Output Signals ......................................................................................................................... 24
Table 6-5Power Signal............................................................................................................................ 24
Table 6-6Timing...................................................................................................................................... 26
Table 7-1RS-232 connector pinout ......................................................................................................... 27
Table 8-1Multiplier Mnemonics ............................................................................................................. 31
Table 9-1AT520 Resistance Measurement.............................................................................................. 38
Table 9-2AT520 Voltage Measurement................................................................................................... 38
Table 9-3AT520SE Resistance Measurement ......................................................................................... 38
Table 9-4AT520SE Voltage Measurement .............................................................................................. 39
Table 9-5AT520L Resistance Measurement ........................................................................................... 39
Table 9-6AT520L Voltage Measurement ................................................................................................ 39
Table 9-7AT520M Resistance Measurement .......................................................................................... 39
Table 9-8AT520M Voltage Measurement ............................................................................................... 39

AT520/AT520SE/AT520L/AT520M User’s Guide
8
1. UnpackingandPreparation
This chapter describes how to set up and start the AT520x AC Milliohm Meter.
Incoming Inspection
Power Requirements
Setting up the Fuse
How to Remove the Handle
Environmental Requirements
Cleaning
1.1 IncomingInspection
After you receive the instrument, carry out checks during unpacking according to the
following procedure.
WARNING
If the external face of the instrument (such as the cover, front/rear panel, VFD
screen, power switch, and port connectors) appears to have been damaged during
transport, do not turn on the power switch. Otherwise, you may get an electrical
shock.
Check that the packing box or shock-absorbing material used to package the instrument
has not been damaged.
Referring to <Packing List> in the packing box, check that all packaged items supplied
with the meter have been provided as per the specified optioned.
NOTE
If an abnormality is detected, contact the company and transport the meter to your
nearest Applent Instruments sales or service office. For inspection by the transport
company, save the packing box, shock-absorbing material, and packaged items as you
received them.
1.2 SettingupFuse
Figure 1-1 Fuse Holder
~Line: 90VAC–115VAC
20VA MAX
Fuse: 250V 1A
Slow Blow
Please use the following fuse type.
UL/CSA type, Slow-Blow, 5×20-mm miniature fuse, 1A, 250 V
When you need a fuse, contact your nearest Applent Instruments sales or service office.
To verify and replace the fuse, remove the power cable and pull out the fuse holder.

Unpacking and Preparation 9
NOTE Two fuses in Fuse Holder.
1.3 EnvironmentalRequirements
Set up the AT520x where the following environmental requirements are satisfied.
Operating Environments
Ensure that the operating environment meets the following requirements.
Temperature: 0C to 55C
Temperature range at calibration: 23C±5C (<1C deviation from the temperature when
performing calibration)
Humidity: 15% to 85% at wet bulb temperature ≤40°C (non-condensation) Altitude:
0 to 2,000m
Vibration: Max. 0.5 G, 5 Hz to 500 Hz
1.4 Cleaning
To prevent electrical shock, disconnect the AT520x 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 AT520x internally.
WARNING: Don’t Use Organic Solvents (such as alcohol or gasoline) to clean the
Instrument.
1.5 HowtoRemovetheHandle
A handle kit is attached to the AT520x:

AT520/AT520SE/AT520L/AT520M User’s Guide
10
Figure 1-2 How to remove the handle
1 Retracted

3 Carrying Position

2 Extended
Remove Handle（Lift the handle perpendicular to the unit while pulling it in the direction of 1.）

Overview 11
2. Overview
This chapter contains general information about AT520x .The information is organized as follows
Introduction
Main Specifications
Feature overview
2.1 Introduction
Thank you for purchasing AT520x AC Milliohm meter.
The Applent AT520x completes with comparator function and external interface utilizing
the principles of the AC 4-terminal method that gives priority to line use and offers high
speed, high accuracy and high resolution. External output terminal, external control
terminal and RS-232C interface are standard features. The instrument also features an
m-Ohm and V mode that allows simultaneous measurement and comparison of battery
internal resistance and open-circuit voltage. This Meter is highly suitable for battery
inspection lines as one unit can act as both a low-resistance meter and a volt meter.
2.2 FunctionalComparison
Model Resistance Range Voltage Range Accuracy
AT520 0.001mΩ-3.2k

0.0001~60.000V 0.3%
AT520SE 0.01mΩ-3.2k

0.001~60.00V 0.5%
AT520L 0.01mΩ-32

0.001~60.00V 0.5%
AT520M 0.01mΩ-32

0.001~100.00V 0.5%
2.3 MainSpecificationsandFeatures
Some main specifications of the AT520x include:
Full AT520x specifications are included in Section 7.
Uses 4-terminal measurement method, AT520x is capable of accurate resistance
measurements independent of lead resistance or contact resistance generated between the
lead and the DUT.
Automatic test range or 7 manual ranges.
20mV peak voltage max (Open-circuit terminal voltage)
High-speed measurement: 20 readers per second.
Dual Display: Resistance and DC Voltage.
Trigger Mode: Internal Trig, Manual Trig, Remote Trig, and External Trig mode.
Battery measurement:
AT520x simultaneously measures resistance and DC voltage, so it is capable of making a
combined GD/NG judgment possible for internal resistance and open-circuit voltage.

AT520/AT520SE/AT520L/AT520M User’s Guide
12
High brightness VFD
Calibration (Zeroing) Function:
Short zeroing
Comparator Function:
Up to 30 tables of comparator settings and Output HI/IN/LO and GD/NG io signals.
Interface:
Built-in RS232C: Used SCPI with single 3-wire serial interface
Handler (AT520): Output the results of comparator, EOC signal and input the numbers of
the compare file, Trigger signal from the PLC.

Start up 13
3. Startup
This chapter describes names and functions of the front panel, rear panel, and screen
display and provides the basic procedures for operating AT520x.
Front panel summary
Rear panel summary
VFD
3.1 Frontpanel
Figure 3-1 Front panel
Comp Rate
Range
Comparator 30mV Limit I-Mode
Remote
Shift
Data
Key Lock Beeper
Relative
Clear
Brightness
0.+/-
123
456
789
Trig
Esc Enter
p
nm
k

MG
Trigger
AC Ohmmeter
Beep
-%
+
Hold
Drive Sense
UNKNOWN
AT520SE
!Applent
!
←
1
2
3
4
5
6
7
Table 3-1 Front panel description
No. Name Description
1 POWER SWITCH Push down: ON, Push up: OFF
2 VFD Displays measurement results, instrument status and user’s
interface menus.
3 Knob To choose menu item and input number
4 Terminals The 4-terminal Kelvin chip leads connect to the input
terminal
5 Keypad II Multi-function keys: Numeric, 1st Function and 2nd
Function.
6 Shift Key to press before 2nd Function
7 Keypad I Dual-Function keys: 1st Function and 2n
d
Function.

AT520/AT520SE/AT520L/AT520M User’s Guide
14
3.2 Realpanel
Figure 3-2 Real panel
123
4
Table 3-2 Real panel description
No. Name Description
1 GND
2 Handler Interface AT520 only
3 Power Inlet Built-in fuse type
4 RS-232C Interface
3.3 KeypadI
Figure 3-3 Keypad I
Comp Rate
Comparator 30mV Limit I-Mode Relative
Clear-%
Table 3-3 Keypad I description
No. Name Description
1 Comp Turn ON/OFF Comparator
2 (Shift)Comparator Setup the comparator
3 -% Deviation display.
Include: Absolute deviation（ABS），Deviation display
（%），and Comparator bin.
4 (Shift)30mV Limit Open-circuit terminal voltage limiter:
Turn ON/OFF 30mV Limit function
5 Rate Test rate: Slow/Med/Fast
6 (Shift)I-Mode Choose the test parameter
7 Clear Short Correction
8 Relative Relative zeroing value:
The REL indicator lit means the relative value is ON. If
the Relative is off, measurement results will not remove
the value of short-circuit is cleared.

Start up 15
Figure 3-4 Keypad II
Range
Remote
Data
Key Lock Beeper
jBrightness
0.+/-
123
456
789
Trig
Esc Enter
p
nm
k

MG
Trigger
Beep
Hold
←
Table 3-4 Keypad II description
No. Name Description
1 Data Hold
2 (Shift)Key Lock Keypad Locked
3 Beep Beep ON/OF
4 (Shift)Beeper Setup Beep
5 Range Auto-range ON/OFF
6 (Shift)Remote Enable RS-232C and setup baud rate.
7 ./+/-/0~9 Numeric keys.
7 (Shift)p/n//m/k/M/G Unit
8 Brightness Adjust VFD brightness
9 ESC Exit and back to measurement mode.
10 Enter Determine settings.
3.4 VFD
Figure 3-5 VFD
Table 3-5 VFD description
ID Name Description (Lit)
!Trade Mark
RS-232C Remote Interface (RS-232C) ON.

AT520/AT520SE/AT520L/AT520M User’s Guide
16
ID Name Description (Lit)

Beep Beep ON
AUTO Auto range Auto ranging enabled
REL Relative Relative is ON
NG Not Good Voltage Not Good(Fail)
GD Good Voltage Good(Pass)
Hi High(NG) Resistance beyond the upper limit
IN In Resistance Pass
Lo Low(NG) Resistance beyond the lower limit
COMP Comparator Comparator is ON
SET Comparator Set
HIGH Upper The upper limits of the comparator
LOW Lower The lower limits of the comparator
Keypad Lock
DHData Hold
EX External Trigger
Trig Manual Trigger
F M S Sampling rate F: Fast, M:Medium, S:Slow
VLMT Voltage Limit Open-circuit terminal voltage is limited to 20mV
Range No.
Record No.
Shift Shift Shifted to the 2nd Function
3.5 PowerOn/Off
Power On
Power Off
3.5.1 Warm‐upTime
AT520x is ready to be used as soon as the power-up sequence has completed. However,
to achieve the accuracy rating, warm up the instrument for 30 minutes.

Configuration 17
4. Configuration
This chapter describes how to configure AT520x. Include:
Connect to Device under Test (DUT)
Setting the measurement range
Sampling Rate
Clear zero correction (Zero adjust)
Relative value
Voltage Limiter
Let beep on/off
Deviation Display Mode
Lock out the keypad
4.1 ConnecttoDeviceunderTest(DUT)
Figure 4-1 Connect to DUT
Be sure to ensure the floating state for a battery circuit with voltage exceeding 60VDC.
4.2 SettingtheMeasurementRange
For any measurement range, the maximum accuracy is obtained when the measured
impedance is close to the full-scale value of the measurement range being used.
Conversely, if the measured impedance is much lower than the full-scale value of
measurement range being used, the measurement accuracy will be reduced. This
sometimes cause a discontinuity occurs in the measurement values at the measurement
range boundaries. If measurement range is set to Auto range, the impedance curve will
skip when impedance range change occurs. To prevent this from occurring, the impedance
range should be set to the Hold range mode.
Use the LEFT, RIGHT and AUTO keys to select the desired range.
Press the Range key to select auto-range.
Table 4-1 Range number, range resistance and range change process (AT520)
No. Range Resistance Range up Range down
1 10m
31m

310m

3.1

31

310


30m

300m

3

30

300

2 100m
3 1
4 10
5 100
6 1k

AT520/AT520SE/AT520L/AT520M User’s Guide
18
Press Shift + Range to select the voltage range (AT520/AT520SE/AT520L).
No. Range Maximum indication Resolution
1 6V

6.0000V 100V
2 60V

60.000V 1mV
AT520M
No. Range Maximum indication Resolution
1 10V

10.000V 1mV
2 100V

100.00V 10mV
Note
1. When auto-range is selected, both resistance and voltage ranges are set to auto-range
mode.
2. If the range is not determined in auto-range mode, perform a zero-adjust.
4.3 SettingtheSamplingRate
The RATE operation sets the integration time of the A/D converter, the period of time the
input signal is measured (also known as aperture). The integration time affects the usable
digits and the amount of reading noise.
The RATE items are explained as follows, you can press Rate key to choose.
Fast: 20 readings/s. Use FAST if speed is of primary importance, at the expense of
increased reading noise and fewer usable digits.
Medium: 6 readings/s. Use Medium when a compromise between noise performance and
speed is acceptable.
Slow: 1 readings/s. SLOW provides better noise performance at the expense of speed.
4.4 ShortClearZeroCorrection
The SHORT correction function reduces the measurement error due to the residual
impedance existing between the UNKNOWN terminals and the DUT.
Step1: Under measurement mode, connect the leads as shown below:
Right connection:
Wrong connection:
Step2: Press Clear Key when the value observed in the VFD stabilizes.
Step3: After Clear Zero Correction, AT520x returns to measurement mode.
4.5 ChooseMeasureParameter（AT520）
Step1: Under measurement mode, Press Shift Key. “Shift” appears lit on the VFD.
Step2: Press Rate (I-Mode) key.
Step3: To switch measure parameter as below:
R-
X-

Configuration 19
Z-

L-
4.6 Relativevalue
Relative value is a function used to return the clear-Zero value to their default value.
Step1: Under measurement mode, Press Shift Key. “Shift” appears lit on the VFD.
Step2: Press Clear (Relative) key. “REL” disappears.
Step3: The clear-zero value in full resistance and voltage ranges are returned to their default
values.
4.7 VoltageLimiter
The voltage limiter may be set. If it is set, the open-circle voltage applied to the DUT is
limited to a maximum of 30mVpeak (typical 20mVpeak). This protects the oxide film on
the contact surface of the DUT. If you use AT520x to test battery, keep voltage limiter
OFF.
Step1: Under measurement mode, Press Shift Key. “Shift” appears lit on the VFD.
Step2: Press -% (30mV Limit) key. “VLMT” appears lit.
4.8 SetbeepON/OFF
When the beep is set to ON, the buzzer can be set to sound according to the result of the
comparator operation.
Step1: Under measurement mode
Step2: Press Beep key. “ ” appears lit.
4.9 DeviationDisplayMode
Step1: Under measurement mode
Step2: Press -% key to select items as below
Absolute deviation

AT520/AT520SE/AT520L/AT520M User’s Guide
20
% Deviation display
High/In/Low The results of comparator
Step3: The VFD no.2 line will display the deviation value.
ABS = Measurement Value – Nominal Value
% = ABS / Nominal Value * 100
4.10 Lockoutthekeypad
Step1: Under measurement mode
Step2: Press Shift Key Lock key to lock/unlocked the keypad.
Step3: The VFD no.2 line will display the deviation value.

indicator lit means the keypad is locked.