B+K precision BK8510B User manual

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Contents
1 General Information 5
1.1 Product Overview 5
1.2 Package Contents 5
1.3 Product Dimensions 6
1.4 Rackmount Installation 6
1.5 Front Panel Overview 6
1.5.1 Combination Keys 7
1.6 Rear Panel Overview 8
1.7 Display Overview 9
2 Getting Started 10
2.1 Input Power 10
2.2 Fuse Requirements 10
2.2.1 Fuse Replacement 10
2.3 Input Connections 10
2.4 Preliminary Check 11
2.4.1 Verify AC Input Voltage 11
2.4.2 Self-test Errors 12
2.4.3 Input Check 12
2.4.4 Check Model and Firmware Version 12
3 Front Panel Operation 13
3.1 Local Mode/Remote Mode 13
3.2 Constant Current (CC) Mode 13
3.2.1 Congure CC Parameters 13
3.3 Slew Rate Measurement and Actual Transition time 14
3.4 Constant Voltage (CV) Mode 14
3.4.1 Congure CV Parameters 14
3.5 Constant Power (CW) Mode 14
3.5.1 Congure CW Parameters 14
3.6 Constant Resistance (CR) Mode 15
3.6.1 Congure CR Parameters 15
4 Front Panel Operation 16
4.1 Local Mode/Remote Mode 16
4.2 Constant Current (CC) Mode 16
4.2.1 Congure CC Parameters 16
4.3 Slew Rate Measurement and Actual Transition time 17
4.4 Constant Voltage (CV) Mode 17
4.4.1 Congure CV Parameters 17
4.5 Constant Power (CW) Mode 17
4.5.1 Congure CW Parameters 17
4.6 Constant Resistance (CR) Mode 18
4.6.1 Congure CR Parameters 18
4.7 CR-LED Test Function 18
4.7.1 Setup 18
4.7.2 External Triggering 19

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5 Rear Panel Functions 20
5.1 Remote Sensing 20
5.2 External Triggering 21
5.3 Current Monitoring (I Monitor) 21
5.3.1 Remote Sensing 21
5.3.2 Current Monitoring (I Monitor) 21
6 Advanced Functions 22
6.1 Short Operation 22
6.2 Short-circuit Analog Function 22
6.3 Transient Operation 22
6.3.1 CC Mode 23
6.3.2 CV, CW, and CR modes 23
6.4 LIST Operation 23
6.4.1 Congure List 24
6.4.2 Run List 24
6.4.3 Disable List Mode 25
6.5 Battery Test Function 25
6.5.1 Test Conguration 25
6.5.2 Enable Battery Test Mode 26
6.5.3 Recall Battery File 26
6.5.4 Start Battery Test 26
6.6 Program Mode 26
6.6.1 Example: Small AC/DC power supply test 26
6.6.2 Start Auto Test File 31
6.6.3 Recall Test File 31
6.7 Measurement of Voltage Rise Time 31
6.7.1 Set initial Voltage and Final Voltage 31
6.8 Ripple Function 32
7 Conguration Functions 33
7.1 VON Function 33
7.2 Menu Operation 33
7.3 System Menu 33
7.4 Menu Options 33
7.5 System Menu (System) 34
7.6 Cong Menu 35
8 System Settings 36
8.1 Run Recall Edit 36
8.2 To recall the settings 36
8.3 To run the OPP test 36
8.4 Key Lock 36
8.5 Restore Factory Default Settings 37
8.5.1 Congure Power-On State 37
8.5.2 Load On Knob 38
8.5.3 Congure Trigger Source 38
8.5.4 Save/Recall Instrument Settings 38
8.5.5 Select Storage Group 39
8.5.6 Save Settings 39
8.5.7 Recall Settings 39
8.5.8 Display Input On Timer 40
8.5.9 Remote Interface Setup 40
8.5.10 RS-232 40
8.5.11 CONFIG Menu 41
8.5.11.1 Von Operation 41

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8.5.12 Congure Protection Settings 41
8.5.13 PROTECT MENU 41
8.5.14 Max-P A-Limit P-Limit Time 41
8.5.15 Overcurrent Protection (OCP) 42
8.5.16 Overpower Protection (OPP) 43
8.5.17 Recall OPP File 44
8.5.18 Overvoltage Protection (OVP) 45
8.5.19 Over-temperature Protection (OTP) 45
8.5.20 Reverse Voltage Protection (LRV/RRV) 45
8.5.21 Congure Timed Input 45
8.5.22 Measurement Congurations 46
9 Protection Functions 47
9.1 OCP Test Function 47
9.2 OPP Test Function 48
9.3 OPP TEST 48
9.4 Over Voltage Protection (OVP) 48
9.5 Over Current Protection (OCP) 49
9.6 Over Power Protection (OPP) 49
9.7 Over Temperature Protection (OTP) 49
9.8 Reverse Voltage Protection (LRV) 50
10 Remote Operation 51
10.1 Interface Connection 51
10.2 Serial Interface 51
10.2.1 GPIB 51
10.2.2 USBTMC 51
10.2.3 Remote Commands 51
11 Troubleshooting Guide 52
11.1 General 52
11.2 Remote Control 52
11.3 Error Information References 52
11.4 Exception handling 52
12 Specications 54
13 Service Information 55
14 LIMITED THREE-YEAR WARRANTY 56

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General Information
1.1 Product Overview
The 8500B Series DC Electronic Loads are versatile instruments used for static and dynamic testing of DC power supplies,
batteries, DC-to-DC converters, battery chargers, and other applications including fuel-cell, and solar cell test. Primary
modes include constant voltage (CV), constant current (CC), constant resistance (CR), and constant power (CW). A
wide range of dynamic loading applications can also be simulated through user-programmable slew rates, load levels,
duration, and conducting voltage. Further, transient, list mode, battery mode, and LED modes further extend testing
capabilities. Versatile triggering options allow the dynamic load behavior to be synchronized with other events. The DC
load is remotely programmable via the TTL serial interface. This interface requires 0-5V signal levels and can connect
to typical serial ports via an adapter such as the IT-E132B.
Features:
•CC/CV/CR/CW operating modes
•List mode
•Transient mode
•Measurement speed up to 40 kHz
•Remote sense function
•Battery test function
•OCP and OPP automatic test
•CR-LED function
•Store/recall up to 100 setups
•Analog current monitoring
•Adjustable slew rate in CC mode
•OVP/OCP/OPP/OTP and reverse voltage protection
1.2 Package Contents
Please inspect the instrument mechanically and electrically upon receiving it. Unpack all items from the shipping carton,
and check for any obvious signs of physical damage that may have occurred during transportation. Report any damage
to the shipping agent immediately. Save the original packing carton for possible future reshipment. Every instrument is
shipped with the following contents:
•8500B series DC Electronic load
•IT-E132B USB to TTL adapter
•AC Power Cord
•Certicate of Calibration
•Test Report

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Verify that all items above are included. If anything is missing, please contact B&K Precision.
1.3 Product Dimensions
All models are designed to t in a standard 19-inch rackmount. The dimensions are shown in Figure 1.1.
Figure 1.1 External Dimensions - Half-rack models
1.4 Rackmount Installation
The instrument can be installed in a standard 19 inch rack. For half-rack models, the optional rackmount kit IT-E151 is
required. Figure 1.2 shows one of the half-rack sized units using the IT-E151 rackmount kit. This rackmount kit also
accomodates up to two half-rack models installed side by side. The full size 8514B includes rack mounting ears.
Figure 1.2 Half-Rack sized Unit
1.5 Front Panel Overview
See Figure 1.3.

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Item Description
1 VFD Display
2 Power Switch
3 Numeric Input and Advanced Functions
4 Mode keys and Input Control
5 Navigation Keys
6 Input Terminals
7 Rotary Input Knob
Figure 1.3 Front Panel
1.5.1 Combination Keys
Press button rst and then other keys to activate the more advanced functions.
+Turn short circuit on or o.
+Start or stop transient condition.
+Set LIST operation parameters.
+Store the DC Load state in non-volatile memory.
+Turn on or o battery testing function.
+Enter auto test function.
+Display product’s Model/SN/Version.

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+System menu setting
+Congure menu setting
+Press this button if you need a pause when running an auto test le.
+Cause an immediate trigger.
+Enter OCP test function.
+Set detailed parameters in CC/CV/CW/CRmode.
+Enter OPP test function.
+Recall the DC Load state from non-volatile memory.
+Key lock function
1.6 Rear Panel Overview
The rear panel connections are shown in Figure 1.4.
Item Description
1 Power Input and Fuse Holder
2 AC Voltage Switch
3 Current Monitor Output
4 Remote Sense and Trigger Input
5 TTL (5V) Communication DE-9 Connector
Figure 1.4 Rear Panel

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1.7 Display Overview
Item Description
1 Measured Voltage
2 Measured Current
3 Measured Power
4 Set Value
5 Input O indicator, lit when input is o
6 Operation mode indicators (CC, CV, CW, CR)
12 Remote control active indicator
13 Error indicator
14 Waiting for Trigger indicator
15 Timer indicator
16 External indicator
16 Remote Sense active indicator
17 Protection event indicator
18 Auto range
19 Key Lock indicator
20 Shift indicator

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Getting Started
Before connecting and powering up the instrument, please review and go through the instructions in this chapter.
2.1 Input Power
The load has a selectable AC input that accepts line voltage input within:
Voltage Frequency
115 V (+/-10%) or 230 V (+/- 10%) 47 Hz – 63 Hz
Table 2.1 Input Power Requirements
Use the line voltage selector switch in the back to switch between 110 V and 220 V operation.
Disconnect all cables including the power cord from the instrument when changing the instrument’s line
voltage. After changing the line voltage setting, ensure the instrument has fuses of the proper ratings and types for
the selected line voltage before applying line power.
2.2 Fuse Requirements
An AC input fuse is necessary when powering the instrument. Below is a table of the fuse required for all models operating
with either 110 VAC or 220 VAC input. See Table 2.2. The fuses are 5mm x 20mm High Energy Slow Blow type
(ceramic casing with sand ll).
Model Fuse Specication (110 VAC) Fuse Specication (220 VAC)
8542B 1.25 A, 250 V 500 mA, 250 V
8500B 1.25 A, 250 V 500 mA, 250 V
8502B 1.25 A, 250 V 500 mA, 250 V
8510B 2.5 A, 250 V 1.25 A, 250 V
8514B 2.5 A, 250 V 1.25 A, 250 V
Table 2.2 Fuse Ratings
2.2.1 Fuse Replacement
Follow the steps below to replace to check the fuse:
1. Locate the fuse box next to the AC input connector in the rear panel, see Figure 2.1.
2. With a small at blade screwdriver, insert into the fuse box slit to pull and slide out the fuse box as indicated below.
3. Check and replace fuse (if necessary) for the desired line voltage operation.
2.3 Input Connections
The main DC input terminal is a screw type binding post terminal located in the front panel, holes are included for
inserting wires, and the binding post also includes “banana jack” connections. Each connection allows for dierent

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Figure 2.1 Fuse Holder
current levels. The “banana” input is capable of up to 10 A of current. Any more current is not recommended and could
lead to excessive connector heating, melting and worse.
Note: The screws on the terminals can be completely removed to allow for ring type adapters. The screw posts are
7mm in diameter.
Due to the high current rating of the DC load, proper wire sizes are necessary for safe connectivity and to prevent wires
from overheating.
Before connecting wires to the input terminals, turn OFF the load to avoid damage to the instrument and
the device under test (DUT).
High Current Connection Low (<10 A) Current Connection
Figure 2.2 Input Connections
2.4 Preliminary Check
Complete the steps in this section to verify that the load is ready for use.
2.4.1 Verify AC Input Voltage
Verify and check to make sure proper AC voltages are available to power the instrument. The AC voltage range must
meet the acceptable specication as explained in Section ??.
Connect AC power cord to the AC receptacle in the rear panel and press the power switch to the ON position to turn
ON the instrument. It will run through a self test procedure with the screen shown below:

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2.4.2 Self-test Errors
Connect AC power cord to the AC receptacle in the rear panel and press the power switch to the ON position to turn
ON the instrument. Various elements of the system are checked during the power-on self test routine. If any occur, they
are reported during the power-up procedure. See Section 11 for troubleshooting and error information details. During
self-test, the display displays “System Init”, and dots are displayed showing the test progress level.
2.4.3 Input Check
Follow the steps below to check that the load is operating correctly, and that the load elements (power transistors) are
not damaged. A DC power supply rated for at least 5V and 1 A is required for this check.
1. Connect the input terminal to a DC power supply and congure the supply to output 5 V and current limit to 1 A.
2. Power on the load. The display will show the “OFF” annunciator above the voltage display.
3. Turn on the DC power supply’s output. Observe the load’s measured voltage display, it should read approximately 5
V.
4. Press the “CC” button to enable the constant current load mode.
5. Use the keypad to enter 0.5 A. Press the Enter key to set the value.
6. The display should show CC = 0.500A on the bottom right.
7. Press “On/O” to enable the load. The “On/O” button should light up, and the “O” indicator on screen should
disappear. The measured current should now display a value close to 0.5 A.
8. This setup veries that the load is drawing power correctly from the power supply.
If the load does not show 5 V, or shows signicant current draw from the connected power supply, the load may be
damaged and need service. If when the supply is connected, showing 5 V on the load’s display, and no current is drawn,
the load may be damaged and need service.
Note: If the load is not drawing power from the DC power supply, check all load protection limits and settings within
the menu to verify that the load is congured to allow drawing power at 5V, 0.500 A. Also, verify that the CC mode
parameters are setup to operate within the congured valid ranges by pressing +
If after checking all of the above, and verifying the power supply used for testing is not at fault, contact B&K for further
assistance.
2.4.4 Check Model and Firmware Version
The model and rmware version can be veried by using the *IDN? query remote command. It can also be found from
the front panel:
1. Press and
2. The display will show the following:
3. This shows the model to be a BK8542B with Firmware: 1.45
4. Press (esc) to return to the normal display.

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Front Panel Operation
The electronic load provides the following modes:
•Constant current (CC) operation mode
•Constant voltage (CV) operation mode
•Constant resistance (CR) operation mode
•Constant power (CW) operation mode
3.1 Local Mode/Remote Mode
The 8500B series can either be operated locally or remotely. When in “Remote” mode, the RMT indicator will be lit.
When in this mode, the front panel of the load is disabled and all commands are issued via the serial interface. In order
to exit “Remote” mode and work in “Local” mode, press the “Local” button. This is the small grey button on the left
hand side of the numeric keypad.
3.2 Constant Current (CC) Mode
In this mode, the load will draw the specied current as long as the source is capable of delivering it. The load uses
transistors in parallel to implement the load circuit, and as such there are some limits. For example, the load has a nite
minimum resistance determined by the RdsOn of the transistors. Next, given the resistance limits, there is a limit to the
amount of current that may be drawn for a given voltage. The datasheet shows curves for this limit in the section called
“Low Voltage Operation”. Please refer to the datasheet for details for each model.
3.2.1 Congure CC Parameters
There are several parameters that should be setup prior to operating in CC mode. First, enable the “CC” mode of
operation by pressing the CC mode key. Next, enter the setup menu by pressing “Shift” and then the “CV” key. Above
the “CV” key, “Setup” is written. The following are the available menu items, scroll through them with the up/down
arrow keys or by entering a value and pressing enter.
Range This denes the maximum allowed current set value. Use this limit to protect against acciden-
tally entering excessive current values either from the keypad or dial.
High This is the voltage high limit for the automatic test mode, it does not apply otherwise. During
automatic test mode, the device under test (DUT) must be operating below the congured value
for the test to PASS upon completion. If the DUT operates above the congured value, the test
will FAIL upon completion.
Low This parameter refers to the voltage low limit for the automatic test mode. During automatic
test mode, the DUT must be operating above the congured value for the test to PASS upon
completion. If the DUT operates below the congured value, the test will FAIL upon comple-
tion.
Rise Up/ Fall Down These parameters dene the current slew rate of the load as it changes to a new programmed
value. The programmed slew rate takes eect immediately when set, so if the transient or trig-
gered modes are active, it will apply immediately.

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3.3 Slew Rate Measurement and Actual Transition time
Current slew rate is dened as the change in current over time. A programmable slew rate allows a controlled transition
from one load setting to another. The actual transition time is dened as the time for the input to change from 10% to
90%, or 90% to 10% of the programmed current values. The graph below illustrates slew rate measurements.
Between the 10% and 90% region, the slew rate can be measured by observing the steepest slope portion. In case of very
large load changes, e.g. from no load to full load, the actual transition time will be larger than the expected (measured)
time. For this reason, the rmware allows the user to program slew rate values outside of the specied slew rate ranges.
The minimum transition time for all programmable slew rates is also limited in cases where the transition from one setting
to another is very small, due to bandwidth limitations of the load.
3.4 Constant Voltage (CV) Mode
In this mode, the electronic load will attempt to sink enough current to control the source voltage to the programmed
value.
3.4.1 Congure CV Parameters
There are several parameters that should be set up prior to operating in CV mode. Press so that it lights up, then press
) and to access Setup for CV mode. The setup menu will be shown:
Range This value will also act as a limit to how much voltage the load can be congured.
High This is the current upper limit for the automatic test mode. The system must be operating be-
low the congured value for the test to PASS upon completion. If the DUT operates above this
value, the test will FAIL.
Low This is the current lower limit for the automatic test mode. The system must be operating be-
low the congured value for the test to PASS upon completion. If the DUT operates below this
value, the test will FAIL.
3.5 Constant Power (CW) Mode
In this mode, the electronic load will consume a constant power. When input voltage increases, the input current will
decrease, while power (P = V*I) will remain the same. This is a sampled system, so the performance is not as fast as in
CC and CV modes.
3.5.1 Congure CW Parameters
There are several parameters that should be set up prior to operating in CW mode. Press
so that it lights up, then press )and to access “Setup” for CW mode. The setup menu will be shown:
The setup parameters are: Range, High (Voltage limit), and Low (Voltage limit). Use the
) keys to select each parameter, and use the numeric keypad to change the value. Press to conrm the change.
Range This value will also act as a limit the allowed power setting value.
High This parameter sets the upper voltage limit for the automatic test mode. If the voltage exceeds
this upper limit during the test, the test will fail.
High This parameter sets the lower voltage limit for the automatic test mode. If the voltage exceeds
this lower limit during the test, the test will fail.

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3.6 Constant Resistance (CR) Mode
In this mode, the electronic load approximates a resistor. The current draw is varied by the load according to the input
voltage. The performance of this mode is not as fast as in CC or CV mode. This is because it is a sampled system and
response to changing input takes a nite amount of time.
3.6.1 Congure CR Parameters
There are several parameters that should be set up prior to operating in CR mode. Press
so that it lights up, then press )and to access Setup for CR mode. The setup menu will be shown:
The setup parameters are: Range, High (Voltage limit), and Low (Voltage limit). Use the (arrow keys) key to select each
parameter, and use the numeric keypad to change the value. Press (enter) to conrm the change.
Range This value will also act as a limit the allowed resistance setting value.
High This parameter sets the upper voltage limit for the automatic test mode. If the voltage exceeds
this upper limit during the test, the test will fail.
High This parameter sets the lower voltage limit for the automatic test mode. If the voltage exceeds
this lower limit during the test, the test will fail.

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Front Panel Operation
The electronic load provides the following modes:
•Constant current (CC) operation mode
•Constant voltage (CV) operation mode
•Constant resistance (CR) operation mode
•Constant power (CW) operation mode
4.1 Local Mode/Remote Mode
The 8500B series can either be operated locally or remotely. When in “Remote” mode, the RMT indicator will be lit.
When in this mode, the front panel of the load is disabled and all commands are issued via the serial interface. In order
to exit “Remote” mode and work in “Local” mode, press the “Local” button. This is the small grey button on the left
hand side of the numeric keypad.
4.2 Constant Current (CC) Mode
In this mode, the load will draw the specied current as long as the source is capable of delivering it. The load uses
transistors in parallel to implement the load circuit, and as such there are some limits. For example, the load has a nite
minimum resistance determined by the RdsOn of the transistors. Next, given the resistance limits, there is a limit to the
amount of current that may be drawn for a given voltage. The datasheet shows curves for this limit in the section called
“Low Voltage Operation”. Please refer to the datasheet for details for each model.
4.2.1 Congure CC Parameters
There are several parameters that should be setup prior to operating in CC mode. First, enable the “CC” mode of
operation by pressing the CC mode key. Next, enter the setup menu by pressing “Shift” and then the “CV” key. Above
the “CV” key, “Setup” is written. The following are the available menu items, scroll through them with the up/down
arrow keys or by entering a value and pressing enter.
Range This denes the maximum allowed current set value. Use this limit to protect against acciden-
tally entering excessive current values either from the keypad or dial.
High This is the voltage high limit for the automatic test mode, it does not apply otherwise. During
automatic test mode, the device under test (DUT) must be operating below the congured value
for the test to PASS upon completion. If the DUT operates above the congured value, the test
will FAIL upon completion.
Low This parameter refers to the voltage low limit for the automatic test mode. During automatic
test mode, the DUT must be operating above the congured value for the test to PASS upon
completion. If the DUT operates below the congured value, the test will FAIL upon comple-
tion.
Rise Up/ Fall Down These parameters dene the current slew rate of the load as it changes to a new programmed
value. The programmed slew rate takes eect immediately when set, so if the transient or trig-
gered modes are active, it will apply immediately.

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4.3 Slew Rate Measurement and Actual Transition time
Current slew rate is dened as the change in current over time. A programmable slew rate allows a controlled transition
from one load setting to another. The actual transition time is dened as the time for the input to change from 10% to
90%, or 90% to 10% of the programmed current values. The graph below illustrates slew rate measurements.
Between the 10% and 90% region, the slew rate can be measured by observing the steepest slope portion. In case of very
large load changes, e.g. from no load to full load, the actual transition time will be larger than the expected (measured)
time. For this reason, the rmware allows the user to program slew rate values outside of the specied slew rate ranges.
The minimum transition time for all programmable slew rates is also limited in cases where the transition from one setting
to another is very small, due to bandwidth limitations of the load.
4.4 Constant Voltage (CV) Mode
In this mode, the electronic load will attempt to sink enough current to control the source voltage to the programmed
value.
4.4.1 Congure CV Parameters
There are several parameters that should be set up prior to operating in CV mode. Press so that it lights up, then press
) and to access Setup for CV mode. The setup menu will be shown:
Range This value will also act as a limit to how much voltage the load can be congured.
High This is the current upper limit for the automatic test mode. The system must be operating be-
low the congured value for the test to PASS upon completion. If the DUT operates above this
value, the test will FAIL.
Low This is the current lower limit for the automatic test mode. The system must be operating be-
low the congured value for the test to PASS upon completion. If the DUT operates below this
value, the test will FAIL.
4.5 Constant Power (CW) Mode
In this mode, the electronic load will consume a constant power. When input voltage increases, the input current will
decrease, while power (P = V*I) will remain the same. This is a sampled system, so the performance is not as fast as in
CC and CV modes.
4.5.1 Congure CW Parameters
There are several parameters that should be set up prior to operating in CW mode. Press
so that it lights up, then press )and to access “Setup” for CW mode. The setup menu will be shown:
The setup parameters are: Range, High (Voltage limit), and Low (Voltage limit). Use the
) keys to select each parameter, and use the numeric keypad to change the value. Press to conrm the change.
Range This value will also act as a limit the allowed power setting value.
High This parameter sets the upper voltage limit for the automatic test mode. If the voltage exceeds
this upper limit during the test, the test will fail.
High This parameter sets the lower voltage limit for the automatic test mode. If the voltage exceeds
this lower limit during the test, the test will fail.

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4.6 Constant Resistance (CR) Mode
In this mode, the electronic load approximates a resistor. The current draw is varied by the load according to the input
voltage. The performance of this mode is not as fast as in CC or CV mode. This is because it is a sampled system and
response to changing input takes a nite amount of time.
4.6.1 Congure CR Parameters
There are several parameters that should be set up prior to operating in CR mode. Press
so that it lights up, then press )and to access Setup for CR mode. The setup menu will be shown:
The setup parameters are: Range, High (Voltage limit), and Low (Voltage limit). Use the (arrow keys) key to select each
parameter, and use the numeric keypad to change the value. Press (enter) to conrm the change.
Range This value will also act as a limit the allowed resistance setting value.
High This parameter sets the upper voltage limit for the automatic test mode. If the voltage exceeds
this upper limit during the test, the test will fail.
High This parameter sets the lower voltage limit for the automatic test mode. If the voltage exceeds
this lower limit during the test, the test will fail.
4.7 CR-LED Test Function
The Constant Resistance LED mode roughly simulates a diode characteristic. There are 2 main parameters that are set
to accomplish this, the overall resistance and diode threshold voltage (Vd). At input voltages above the threshold (Vd),
the resistance of the load decreases. For example, set the Vd to 1.6 V, R to 0.1 and connect a current limited power
supply. Set the power supply voltage limit to 5 V, and the current limit to 300 mA. When the input is enabled, the
voltage at the input will be approximately 1.6 V, and the current will be 300 mA. This is equivalent to a resistance of 16
Ohms, much larger than the set value of 0.1 Ohms. See Table 4.1.
Like in CR mode, a resistance value is also set. This value sets the slope of the diode characteristic. A 3 V VD, 0.1
Ohms, and 1.38 A results in 3𝑉 + 0.1Ω ∗ 1.38𝐴 = 3.18𝑉.
Voltage Current Equivalent Load Resistance
1.00 0 innite
1.58 15mA 105 Ohms
1.62 0.215 A 7.5 Ohms
1.63 0.3 5.4 Ohms
1.69 1 A (limit changed) 1.7 Ohms
Table 4.1 CR Mode example
4.7.1 Setup
Enable CR-LED mode via + . Use the arrow keys to move the ashing value “ON”. Press to conrm
and move on. The next screen shows the VD value. Enter the desired threshold voltage and press . CR LED mode
is now setup.
Note: As in CR mode, the control system speed can make loading switching power supplies problematic.

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4.7.2 External Triggering
EXTERNAL:An external trigger is a TTL low signal applied to the Trigger connection on the back panel. This TTL signal
must last for more than 5 ms. A trigger applied to this input is used to change settings (voltage, current , resistance),
toggle between settings in transient- toggle mode, or generate a pulse in pulse mode.
Operation to select the trigger source as external:
[ ] +[8] (system)to enter the menu,use [(right/left)] to select TRIGGER,press ,and then select EXTERNAL. Press
to exit the menu.

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Rear Panel Functions
Item Description
1 Power Input
2 Fuse Holder
3 AC Input Voltage Selection
4 Current Monitor Output
5 Remote Sense/Trigger Input
6 Remote Interface
Figure 5.1 Rear Panel
5.1 Remote Sensing
Remote sensing is used to counteract the eect of lead resistance. For example, if you connect a power supply to the DC
Load, the voltage at the power supply’s terminals will not be the same as the voltage at the DC Load’s terminals if there
is a current owing because of the nite resistance from the wires. Using remote sensing, you can sense the voltage at
the power supply’s terminals, eectively removing the eect of the voltage drop in the connection wire.
Connect the “+” and “-” terminals at the rear of the unit to the power source.
Note:To reduce interference, twist the sense lines together and run together with the wires connecting the load to
the source.
Note:When using remote sensing, the power displayed by the instrument includes both the power dissipated inside
the instrument and the power dissipated in the leads from the power supply to the DC Load’s input terminals.