Ametek 251RP Series Owner's manual

801RP / 1251RP Series
AC Power Source
User and Programming
Manual

iii
Important Safety Instructions
Before applying power to the system, verify that your product is configured properly for your
particular application.
WARNING
Hazardous voltages may be present when covers are removed. Qualified
personnel must use extreme caution when servicing this equipment.
Circuit boards, test points, and output voltages also may be floating above
(below) chassis ground.
WARNING
The equipment used contains ESD sensitive ports. When installing
equipment, follow ESD Safety Procedures. Electrostatic discharges might
cause damage to the equipment.
Only qualified personnel who deal with attendant hazards in power supplies, are allowed to perform
installation and servicing.
Ensure that the AC power line ground is connected properly to the Power Rack input connector or
chassis. Similarly, other power ground lines including those to application and maintenance
equipment must be grounded properly for both personnel and equipment safety.
Always ensure that facility AC input power is de-energized prior to connecting or disconnecting any
cable.
In normal operation, the operator does not have access to hazardous voltages within the chassis.
However, depending on the user’s application configuration, HIGH VOLTAGES HAZARDOUS TO
HUMAN SAFETY may be normally generated on the output terminals. The customer/user must
ensure that the output power lines are labeled properly as to the safety hazards and that any
inadvertent contact with hazardous voltages is eliminated.
Guard against risks of electrical shock during open cover checks by not touching any portion of the
electrical circuits. Even when power is off, capacitors may retain an electrical charge. Use safety
glasses during open cover checks to avoid personal injury by any sudden component failure.
Neither AMETEK Programmable Power Inc., San Diego, California, USA, nor any of the subsidiary
sales organizations can accept any responsibility for personnel, material or inconsequential injury,
loss or damage that results from improper use of the equipment and accessories.
SAFETY SYMBOLS

iv
Product Family: 801RP/1251RP Series
Warranty Period: One Year
WARRANTY TERMS
AMETEK Programmable Power, Inc. (“AMETEK”), provides this written warranty covering the
Product stated above, and if the Buyer discovers and notifies AMETEK in writing of any defect in
material or workmanship within the applicable warranty period stated above, then AMETEK may,
at its option: repair or replace the Product; or issue a credit note for the defective Product; or
provide the Buyer with replacement parts for the Product.
The Buyer will, at its expense, return the defective Product or parts thereof to AMETEK in
accordance with the return procedure specified below. AMETEK will, at its expense, deliver the
repaired or replaced Product or parts to the Buyer. Any warranty of AMETEK will not apply if the
Buyer is in default under the Purchase Order Agreement or where the Product or any part
thereof:
is damaged by misuse, accident, negligence or failure to maintain the same as
specified or required by AMETEK;
is damaged by modifications, alterations or attachments thereto which are not
authorized by AMETEK;
is installed or operated contrary to the instructions of AMETEK;
is opened, modified or disassembled in any way without AMETEK’s consent; or
is used in combination with items, articles or materials not authorized by AMETEK.
The Buyer may not assert any claim that the Products are not in conformity with any warranty
until the Buyer has made all payments to AMETEK provided for in the Purchase Order Agreement.
PRODUCT RETURN PROCEDURE
1. Request a Return Material Authorization (RMA) number from the repair facility (must be
done in the country in which it was purchased):
In the USA, contact the AMETEK Repair Department prior to the return of the
product to AMETEK for repair:
Telephone: [phone], ext. 2295 or ext. 2463 (toll free North America)
858-450-0085, ext. 2295 or ext. 2463 (direct)
Outside the United States, contact the nearest Authorized Service Center
(ASC). A full listing can be found either through your local distributor or our
website, www.programmablepower.com, by clicking Support and going to the
Service Centers tab.
2. When requesting an RMA, have the following information ready:
Model number
Serial number
Description of the problem
NOTE: Unauthorized returns will not be accepted and will be returned at the shipper’s expense.
NOTE: A returned product found upon inspection by AMETEK, to be in specification is subject to
an evaluation fee and applicable freight charges.

v
Table of Contents
1. Introduction.................................................................................................................................1
1.1. General Description...................................................................................................................................1
2. Specifications .............................................................................................................................2
2.1. Electrical....................................................................................................................................................2
2.2. Mechanical ................................................................................................................................................5
2.3. Environmental............................................................................................................................................6
2.4. Regulatory.................................................................................................................................................6
2.5. Front Panel Controls..................................................................................................................................7
2.6. Available Options.......................................................................................................................................7
3. Unpacking and Installation .........................................................................................................8
3.1. Unpacking .................................................................................................................................................8
3.2. Power Requirements.................................................................................................................................8
3.3. Mechanical Installation..............................................................................................................................8
3.4. Input Wiring...............................................................................................................................................9
3.5. Output Connections...................................................................................................................................9
3.6. Output Voltage Ranges...........................................................................................................................10
3.7. Functional Test........................................................................................................................................10
4. Front Panel Operation ..............................................................................................................12
4.1. Front Panel Guided Tour.........................................................................................................................12
4.2. How to... ..................................................................................................................................................16
5. Principle of Operation...............................................................................................................19
5.1. General....................................................................................................................................................19
5.2. Overall Description..................................................................................................................................19
5.3. Power Factor Correction Module (PFC) ..................................................................................................19
5.4. DC - DC Converter Module......................................................................................................................20
5.5. 20
5.6. Oscillator Control Board ..........................................................................................................................21
5.7. DC to AC Power Module..........................................................................................................................22
5.8. IEEE 488/ RS232 ....................................................................................................................................22
6. Calibration.................................................................................................................................24
6.1. Calibration Equipment.............................................................................................................................24
6.2. Routine Calibration..................................................................................................................................24
6.3. Non-Routine Calibration ..........................................................................................................................27
7. Service......................................................................................................................................29
7.1. General....................................................................................................................................................29
7.2. Basic Operation.......................................................................................................................................29
7.3. Advanced Troubleshooting......................................................................................................................31
8. Introduction to PGUI32.............................................................................................................34
8.1. About This Program.................................................................................................................................34
8.2. About This Section of the Manual............................................................................................................34
8.3. Program Requirements ...........................................................................................................................34
8.4. RS232C Cable Wiring .............................................................................................................................35
9. PGUI32 Setup and Installation .................................................................................................36
9.1. Connecting the AC Source to the PC When Using RS232 .....................................................................36
9.2. Connecting the AC Source to the PC Using IEEE-488 ...........................................................................36
9.3. Installing the PGUI32 Software ...............................................................................................................36
9.4. Trouble Shooting - RS232C ....................................................................................................................37
9.5. Registration .............................................................................................................................................39

vi
10. Top Assembly Replaceable Parts ............................................................................................ 40
11. Programming Information......................................................................................................... 41
12. Introduction to SCPI ................................................................................................................. 42
12.1. Conventions Used in This Manual .......................................................................................................... 42
12.2. The SCPI Commands and Messages.....................................................................................................42
12.3. Using Queries ......................................................................................................................................... 44
12.4. Structure of a SCPI Message.................................................................................................................. 45
12.5. SCPI Data Formats.................................................................................................................................47
13. System Considerations............................................................................................................. 50
13.1. IEEE Interface......................................................................................................................................... 50
13.2. RS232C Interface....................................................................................................................................50
14. SCPI Command Reference...................................................................................................... 53
14.1. Introduction ............................................................................................................................................. 53
14.2. Subsystem Commands...........................................................................................................................53
14.3. System Commands................................................................................................................................. 60
14.4. Common Commands..............................................................................................................................63
15. Programming Examples........................................................................................................... 69
15.1. Introduction ............................................................................................................................................. 69
15.2. Programming the Output.........................................................................................................................69
15.3. Making Measurements............................................................................................................................ 70
16. Status Registers....................................................................................................................... 71
16.1. Power-On Conditions..............................................................................................................................71
16.2. Standard Event Status Group.................................................................................................................72
16.3. Status Byte Register ............................................................................................................................... 72
16.4. Examples ................................................................................................................................................ 73
17. Index......................................................................................................................................... 77

vii
List of Figures
Figure 3-1: The 801RP/1251RP AC Power Source .......................................................................................8
Figure 3-2: Rear Panel View..........................................................................................................................9
Figure 3-3: Functional test setup..................................................................................................................11
Figure 4-1: Front panel view.........................................................................................................................12
Figure 4-2: Shuttle Knob ..............................................................................................................................14
Figure 5-1: AC Source block diagram..........................................................................................................19
Figure 5-2: Oscillator and controls ...............................................................................................................21
Figure 6-1: Test Equipment Hookup for Routine Output Calibration............................................................25
Figure 6-2: Test Equipment Hook-up for Measurement Calibration.............................................................26
Figure 6-3: Location of Internal Adjustments ...............................................................................................28
Figure 8-1: RS232C Cable Wiring................................................................................................................35
Figure 9-1: System Properties Dialog Box ...................................................................................................38
Figure 9-2: Advanced Port Settings Dialog Box...........................................................................................38
Figure 9-3: COM Port Properties Dialog Box ...............................................................................................39
Figure 12-1: Partial Command Tree.............................................................................................................43
Figure 12-2: Command Message Structure .................................................................................................45
Figure 13-1: GPIB Address Selection Switch..............................................................................................50
Figure 13-2: RS232C Interface cable wiring diagram ..................................................................................52
Figure 16-1: AC Source Status System Model.............................................................................................71
List of Tables
Table 1: Logic Board LED's..........................................................................................................................20
Table 2: Load and current............................................................................................................................24
Table 3: Basic Symptoms.............................................................................................................................29
Table 4: Poor output voltage regulation .......................................................................................................29
Table 5: Overload Light On ..........................................................................................................................29
Table 6: Distorted Output.............................................................................................................................30
Table 7: Unit shuts down after 3-5 seconds.................................................................................................30
Table 8: No output and no lights on front panel ...........................................................................................30
Table 9: No output but "power on" led is lit ..................................................................................................30
Table 10: Replaceable Parts........................................................................................................................40
Table 11: Bit configuration of standard event status enable register ...........................................................64
Table 12: Bit configuration of standard event status register.......................................................................65
Table 13: *RST default parameter values ....................................................................................................67
Table 14: Status register power on condition...............................................................................................67
Table 15: Bit Configuration of Status Byte Register.....................................................................................68
Table 16: Error Messages............................................................................................................................76

1
1. Introduction
This instruction manual contains information on the installation, operation, calibration and
maintenance of the RP Series AC power source.
1.1. General Description
The 801RP/1251RP AC source is a high efficiency, light weight 800VA or 1250VA
programmable AC power source. The output has two voltage ranges of 0-135V or 0-270V
with a frequency range of 16 Hz to 500 Hz. The maximum output current for the 1251RP is
9.2 amps on 135 volts range and 4.6 amps on 270 volts range.
The maximum output current for the 801RP is 6 amps on 135 volt range and 3 amps on 270
volts range.
The universal nominal input can be from 100 volts to 240 volts at 50 Hz or 60 Hz line
frequency.
Simple front panel controls enable the voltage, current limit and frequency to be changed.
An optional RS232C and IEEE 488 interface is available for applications that require remote
control and measurements.

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2. Specifications
All specifications at 25 5 C unless noted otherwise.
2.1. Electrical
2.1.1. Input
Line Voltage: 85V to 264V maximum.
100V to 240V nominal.
Line Current: 15 A RMS max.
Line Frequency: 47-63 Hertz.
Efficiency: 80% (typical) depending on line and load.
Power Factor: 0.95 or greater typical.
Inrush Current: 70 A peak max. at 260V input.
Hold-Up Time: 20 ms (with no effect on output).
Isolation Voltage: Input to output = 2200 VAC, input to chassis = 1350 VAC.
2.1.2. Output
Voltage Range: 0 to 135 V rms or 270 V rms
Voltage Resolution: 0.1 volt
Voltage Accuracy: 1% of range, 50 to 60 Hz.
2% at 400 Hz
Line & Load Regulation: 1% of FS on low range, 0.5% of FS on high range.
Voltage Distortion: 0.5% typical. THD at 50/60 Hz.
Total Power: 800 VA maximum at full scale voltage, either range (Model
801RP).
1250 VA maximum at full scale voltage either range (Model
1251RP).
Note: On the 1251RP, the maximum output power is limited to 1000VA when the input
voltage is below 120VAC.

RP Series March 2011
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Current: 6.0 A rms, 18 A peak (low range, Model 801RP)
3.0 A rms, 9 A peak (high range, Model 801RP)
9.2 A rms, 27.6 A peak (low range, Model 1251RP)
4.6 A rms, 13.8 A peak (high range, Model 1251RP)
Current Limit: 801RP 1251RP
135V range: 0.0 to 6.0 9.2
270V range: 0.0 to 3.0 4.6
Accuracy: Programmed value +5% of maximum current
Frequency Range: Range Resolution
16.0 - 99.9 Hz 0.1 Hz
100 - 500 Hz 1 Hz
Frequency Accuracy: 0.02% of programmed value.
DC Offset Voltage: Less than 25 mV with linear load.
Output Noise: <0.2 volts RMS on 135 range, <0.5 volts RMS on 270 range.
2.1.3. Measurements
Current (TRMS)
Resolution: 0.1 amp
Accuracy: 0.2 amp
Voltage Accessible only through RS232/ IEEE 488 Interface
0 - 250V 251 to 270V
Resolution 1 Volts 2 volts
Accuracy: 4 Volts 6 volts

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2.1.4. System Specification
Non Volatile
Memory Storage: 8 complete instrument setups [ Accessible through RS232C interface
only ].
RS232C Interface: Bi-directional serial interface
[ optional ] 9 pin D-shell connector
Handshake: CTS, RTS
Data bits: 8
Stopbits: 1
Parity: None
Baud rate: 9600
IEEE 488.2 commands and SCPI
IEEE Interface: Bi-directional parallel interface
24 pin D-shell connection
IEEE address: set using DIP switch on rear panel from 0 to 31
IEEE functions: SH1, AH1, T8, L3, RL2
Terminators: LF, CRLF, EOI
IEEE 488.2 commands and SCPI
Remote Inhibit
(Option –RI required)
Rear panel connector:
BNC
Input
Contact closure to ground or logic low TTL
signal required to turn off output.
Automatic recovery when RI signal is
removed.

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2.1.5. Unit protection
Input Overcurrent: Electronic current limit with fuse.
Input Overvoltage
Transients: Surge protection to withstand EN50082-1 (IEC 801-4, 5) levels.
Output Overcurrent: Shutdown, 0.1 second after overcurrent.
Output Overvoltage: Shutdown, recycle input power to reset.
Output Short Circuit: Peak current limit. Shutdown after 0.1 seconds.
Overtemperature: Automatic shutdown.
2.2. Mechanical
Dimensions: 16.51”(419.4mm) width x 3.5”(88.9 mm) height x 22”(558.8mm)
depth chassis size stand-alone configuration.
Unit Weight: 37 lbs.
Material: Aluminum chassis, panels and cover.
Finish: Yellow iridite then painted semi-gloss polyurethane
Cooling: Fan cooled with air intake on the sides and exhaust to the rear.
Internal Construction: Modular sub assemblies.
Chassis Slides: General Devices C300S-118-B308 (use hardware provided to
prevent damage to unit)
Front Panel Mounted
Output Connections:
CEE 7/7 European socket
US domestic Single 5-15R 120V line socket
Rear Panel Mounted
Connections:
RS232C Interface DB 9
IEEE-488 Interface D-shell 24 pin
Output Phoenix Contact HDFK4
Line Input IEC 320

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2.3. Environmental
Operating Temp: 0 degrees to +40 degrees Celsius.
Storage Temp: -40 degrees to +85 degrees Celsius.
Humidity: Operating: 90% RH up to 40 C.
Storage: 90% RH up to 40 C, 75% RH up to 70 C.
Creepage and
Clearance: Rated for Pollution Degree 2.
Insulation: Rated to Installation Category (Overvoltage Category) II
Vibration: Designed to meet NSTA 1A transportation levels.
Shock: Designed to meet NSTA 1A transportation levels.
2.4. Regulatory
Electromagnetic Designed to meet EN50081-1 and EN50082-1 European Emissions
Emissions and and Immunity standards as required for the “CE” mark.
Immunity:
Acoustic Noise: 65 dBA maximum at 0% to 50% load, 75 dBA maximum greater than
50% load to 100% load. Measured at one meter.
Safety: Designed to meet UL3111 and EN61010-1 European safety
standards as required for the “CE” mark.

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2.5. Front Panel Controls
Controls: Shuttle knobs:
Allows continuous change of Voltage, Frequency and Current limit.
Function keys:
Controls Output state, Voltage range and Display mode.
Displays1: Two, 4 digits, 0.5” LED SEGMENT display. For viewing programmed
voltage, frequency, current limit and for displaying measured current.
Status Indicators:
6 LEDs to indicate:
REMOTE, FAULT, OUTPUT (ON/OFF), VOLTAGE RANGE,
FREQUENCY or CURRENT DISPLAY MODE (Refer to paragraph
4.1.2).
2.6. Available Options
The following options are available on 801RP and 1251RP AC power source models.
Option
Description
-IF
Combined IEEE-488 / RS232C interface option.
-L22
Locking knobs. Prevents front panel change of voltage and
frequency.
-RI
Remote Inhibit rear panel input.
-RMS
Rack mount slides
P/N 210367
General Devices Model C300S-118-B308
1801RP and 1251RP Series models shipped before Oct 2005 use LCD style displays instead of LED seven
segment displays. Other than the type of display used, there are no functional differences between both type
801RP and 1251RP Series models.

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3. Unpacking and Installation
3.1. Unpacking
Inspect the unit for any possible shipping damage immediately upon receipt. If damage is
evident, notify the carrier. DO NOT return an instrument to the factory without prior approval.
Do not destroy the packing container until the unit has been inspected for damage in
shipment.
3.2. Power Requirements
The AC Power System has been designed to operate from a single phase AC line voltage.
The nominal operating voltage is from 100V to 240V line input.
Figure 3-1: The 801RP/1251RP AC Power Source
WARNING: Do not connect the unit to a 400-480 service as the result will be a
severely damaged unit.
3.3. Mechanical Installation
The AC Source is a completely self-contained power unit. It can be used free standing on a
bench. The unit is fan cooled, drawing air in from the sides and exhausting at the rear. The
sides of the unit must be kept clear of obstruction and a 4-inch clearance must be maintained
to the rear.

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3.4. Input Wiring
The AC Source is designed to work from a single utility supply. The IEC 320 input connector
will accept a standard IEC line cord with the appropriate mating connector for the utility outlet.
The utility outlet must be properly grounded and be capable of supplying at least 1725 VA at
120V to 240V in order to deliver full output power in the 1251RP.
Note: When using less than 120 V line input, the 1251RP should be used at no more
than 1000 VA output power to limit the input line current to less than 15A.
Figure 3-2: Rear Panel View
3.5. Output Connections
3.5.1. Output Wiring
Front Panel
When the low voltage range is selected, only the single US NEMA 5-15R output socket will
be active. If the high voltage range is selected, only the European CEE7/7 socket will be
active.
Either voltage will be present on the output terminals at the rear panel. There is only one
output terminal on the rear panel marked HIGH and LOW. This output carries the output of
the AC Source in both high and low voltage range. The HIGH and LOW label on the rear
panel refer to output high side and output low side (return) respectively, not to the voltage
range selected.
Note: Do not connect these outputs together as this will cause the unit to fault.

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3.6. Output Voltage Ranges
The AC power source has two standard output voltage ranges 0-135V and 0-270V. The
operator may switch from one range to the other at will with no special precautions except to
remember that the output voltage will go to zero voltage whenever a range change takes
place.
Note: The output changes to the other socket on front panel with a range change.
3.7. Functional Test
CAUTION: Work carefully when performing these tests - hazardous voltages are
present on the input and output during this test.
Refer to Figure 3-3 for the test set up.
1. Connect an oscilloscope, voltmeter and/or distortion analyzer to the AC source output at
the 135 Volt output terminal.
2. Connect the AC power input voltage connections to the AC source input terminals. Turn
on the power switch located at the rear panel.
3. Verify that the front panel LED SEGMENT display reads out the initial start up voltage
and frequency.
4. Select the low voltage range. Set the frequency to 60 Hz with the right shuttle. Select the
current function with the Frequency/Current selector. Set the current limit to the
maximum value using the right shuttle. Set the output voltage to 135V with the left
shuttle.
5. Enable the output by pressing the output “on/off” button in the top right of the front panel.
The green LED above the button will illuminate when the output is on. The output should
be a clean 135 volt AC sinewave having less than 1% distortion.
6. Apply full load (refer to table on Figure 3-3) to the output of the source and verify the
output remains within 2% of the initial 135 volt value. The output should still be clean
and the distortion should still be less than 1% at 60 Hz.
7. Using the right shuttle set the output current limit value to 6 amps. The system should go
into current limit and give an error message on the display (err. -300) that indicates an
output fault condition and the output will go off. Return the current value to the maximum
current and disconnect the load.
8. Repeat steps 4 through 7 but set the output for the following: Hi voltage range and the
current limit to maximum value. The output load should be connected to the Hi range
output connector. The load value is shown in Figure 3-3, for the 270 volt output.
Note: Output connectors must be changed when changing voltage ranges unless
the rear panel output terminals are used.

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In the event the power source does not pass the functional test, refer to the calibration
procedure in Section 6 or call California Instrument‟s customer satisfaction department for
further assistance.
High Range Load
Low Range Load
Load ON/OFF Switch Oscilloscope
AC
Output
or Distortion
Analyzer
Unit
Under 270.0V
Test DMV
AC
Input
Model
Range
Current
Load
801RP
135V
6.0A
22.5
801RP
270V
3.0A
90.0
1251RP
135V
9.2A
14.6
1251RP
270V
4.6A
58.6
Figure 3-3: Functional test setup

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4. Front Panel Operation
4.1. Front Panel Guided Tour
The front panel can be divided in a small number of functional areas:
Output Sockets
Status Indicator lights
Shuttle knobs
LED Segment Display1
Button controls
Figure 4-1: Front panel view
4.1.1. Output Outlets
The Output Sockets are located on the right side of the front panel. It provides connection to
the load from the AC source. When the low voltage range is selected, only the US NEMA 5-
15P output socket will be active. If the high voltage range is selected, only the European
CEE7/7 socket will be active. Refer to Figure 3-1 and Figure 4-1 for socket locations. Both
voltage ranges are present at the rear panel output terminals however. Refer to Figure 3-2.
1: 801RP and 1251RP Series models shipped before Oct 2005 use LCD style displays instead of LED seven
segment displays. Other than the type of display used, there are no functional differences between both type
801RP and 1251RP Series models.

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4.1.2. Status Indicator Lights
Six LED status indicators are located on the front panel. These LED‟s correspond to the
following conditions:
REMOTE The REMOTE LED indicates that the unit is in remote
control mode. If the RS232C interface is used, the REMOTE
state can be enabled by the controller using the SYST:REM
command. Any time the REMOTE LED is lit, the front panel
of the RP Series unit is disabled. There is no LOCAL button
that allows the user to regain control of the front panel. The
SYST:LOC command will enable the front panel controls.
When using IEEE, the remote /local state is controlled by
the REN (Remote Enable) interface line.
FAULT The FAULT LED indicates an output overvoltage or
overtemperature condition. Overtemperature is usually
caused by poor air flow. Check the air flow exhaust at the
rear of the unit to make sure it is not obstructed.
OUTPUT The Output LED indicates the status of the OUTPUT
ON/OFF button. When the Output LED is not lit, the output
voltage is not present at the output socket regardless of the
voltage setting.
RANGE The Range LED indicates the selected output voltage range.
When it is illuminated it indicates the high voltage range has
been programmed.
FREQUENCY Illuminates when the right hand side LED seven segment
display shows the programmed frequency.
CURRENT Illuminates when the right hand side LED seven segment
display shows the programmed current limit or measured
current values.

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4.1.3. The Shuttle Knobs
Counter Clockwise
clockwise
DECREASE INCREASE
Figure 4-2: Shuttle Knob
There are two shuttle knobs located below the LED seven segment displays, which are used
to change setup parameters for voltage, frequency and current limit. The mode button
selects the function of the right shuttle. The right shuttle will control either the frequency or
the current limit as indicated by the indicator above the right LED segment display.
4.1.4. FUNCTION Buttons
There are three function buttons for the Output Voltage Range, Output State and Shuttle
Mode. The following is a description of these buttons:
KEY DESCRIPTION
RANGE The RANGE button is used to change the voltage range
between the low range (0 to 135 volts) and high range (0 to
270 volts). The LED above the switch will light to indicate
the high voltage range selection. The output voltage will be
reset to zero voltage after a range change.
OUTPUT The OUTPUT button will toggle the output to enable or
disable the output. The LED above the button will light when
the output is on. No output voltage will be present when the
OUTPUT button is off despite the level of voltage
programmed.
MODE The MODE button selects the function of the right shuttle
knob and the right LED segment display. The shuttle will
control the output frequency and the display will show the
program frequency value when the mode selection is
frequency. The Shuttle knob will program the current limit
and the display will show its value in the current mode. The
display will revert back to showing the measured current
after 3 seconds from the last movement of the shuttle. The
measurement is updated 4 times per second. The display
mode is indicated by the two LED‟s above the LED segment
display.