B+K precision MDL4U Series User manual

2
Safety Summary
The following safety precautions apply to both operating and maintenance personnel and must be followed during all
phases of operation, service, and repair of this instrument.
Before applying power to this instrument:
• Read and understand the safety and operational information in this manual.
• Apply all the listed safety precautions.
• Verify that the voltage selector at the line power cord input is set to the correct line voltage. Operating the instrument
at an incorrect line voltage will void the warranty.
• Make all connections to the instrument before applying power.
• Do not operate the instrument in ways not specied by this manual or by B&K Precision.
Failure to comply with these precautions or with warnings elsewhere in this manual violates the safety standards of design,
manufacture, and intended use of the instrument. B&K Precision assumes no liability for a customer’s failure to comply
with these requirements.
Category rating
The IEC 61010 standard denes safety category ratings that specify the amount of electrical energy available and the
voltage impulses that may occur on electrical conductors associated with these category ratings. The category rating is
a Roman numeral of I, II, III, or IV. This rating is also accompanied by a maximum voltage of the circuit to be tested,
which denes the voltage impulses expected and required insulation clearances. These categories are:
Category I (CAT I): Measurement instruments whose measurement inputs are not intended to be connected to the
mains supply. The voltages in the environment are typically derived from a limited-energy trans-
former or a battery.
Category II (CAT II): Measurement instruments whose measurement inputs are meant to be connected to the mains
supply at a standard wall outlet or similar sources. Example measurement environments are portable
tools and household appliances.
Category III (CAT III): Measurement instruments whose measurement inputs are meant to be connected to the mains
installation of a building. Examples are measurements inside a building’s circuit breaker panel
or the wiring of permanently-installed motors.
Category IV (CAT IV): Measurement instruments whose measurement inputs are meant to be connected to the primary
power entering a building or other outdoor wiring.
Do not use this instrument in an electrical environment with a higher category rating than what is specied in this manual
for this instrument.
You must ensure that each accessory you use with this instrument has a category rating equal to or higher than the
instrument’s category rating to maintain the instrument’s category rating. Failure to do so will lower the category rating
of the measuring system.

3
Electrical Power
This instrument is intended to be powered from a CATEGORY II mains power environment. The mains power should be
115 V RMS or 230 V RMS. Use only the power cord supplied with the instrument and ensure it is appropriate for your
country of use.
Ground the Instrument
To minimize shock hazard, the instrument chassis and cabinet must be connected to an electrical safety ground. This
instrument is grounded through the ground conductor of the supplied, three-conductor AC line power cable. The power
cable must be plugged into an approved three-conductor electrical outlet. The power jack and mating plug of the power
cable meet IEC safety standards.
Do not alter or defeat the ground connection. Without the safety ground connection, all accessible conductive parts
(including control knobs) may provide an electric shock. Failure to use a properly-grounded approved outlet and the
recommended three-conductor AC line power cable may result in injury or death.
Unless otherwise stated, a ground connection on the instrument’s front or rear panel is for a reference of potential only
and is not to be used as a safety ground. Do not operate in an explosive or ammable atmosphere.
Do not operate the instrument in the presence of ammable gases or vapors, fumes, or nely-divided particulates.
The instrument is designed to be used in oce-type indoor environments. Do not operate the instrument
• In the presence of noxious, corrosive, or ammable fumes, gases, vapors, chemicals, or nely-divided particulates.
• In relative humidity conditions outside the instrument’s specications.
• In environments where there is a danger of any liquid being spilled on the instrument or where any liquid can condense
on the instrument.
• In air temperatures exceeding the specied operating temperatures.
• In atmospheric pressures outside the specied altitude limits or where the surrounding gas is not air.
• In environments with restricted cooling air ow, even if the air temperatures are within specications.
• In direct sunlight.
This instrument is intended to be used in an indoor pollution degree 2 environment. The operating temperature range is
0∘C to 40∘C and 20% to 80% relative humidity, with no condensation allowed. Measurements made by this instrument
may be outside specications if the instrument is used in non-oce-type environments. Such environments may include
rapid temperature or humidity changes, sunlight, vibration and/or mechanical shocks, acoustic noise, electrical noise,
strong electric elds, or strong magnetic elds.

4
Do not operate instrument if damaged
If the instrument is damaged, appears to be damaged, or if any liquid, chemical, or other material gets on or inside the
instrument, remove the instrument’s power cord, remove the instrument from service, label it as not to be operated,
and return the instrument to B&K Precision for repair. Notify B&K Precision of the nature of any contamination of the
instrument.
Clean the instrument only as instructed
Do not clean the instrument, its switches, or its terminals with contact cleaners, abrasives, lubricants, solvents, acids/bases,
or other such chemicals. Clean the instrument only with a clean dry lint-free cloth or as instructed in this manual. Not
for critical applications
This instrument is not authorized for use in contact with the human body or for use as a component in a life-support
device or system.
Do not touch live circuits
Instrument covers must not be removed by operating personnel. Component replacement and internal adjustments must
be made by qualied service-trained maintenance personnel who are aware of the hazards involved when the instrument’s
covers and shields are removed. Under certain conditions, even with the power cord removed, dangerous voltages may
exist when the covers are removed. To avoid injuries, always disconnect the power cord from the instrument, disconnect
all other connections (for example, test leads, computer interface cables, etc.), discharge all circuits, and verify there
are no hazardous voltages present on any conductors by measurements with a properly-operating voltage-sensing device
before touching any internal parts. Verify the voltage-sensing device is working properly before and after making the
measurements by testing with known-operating voltage sources and test for both DC and AC voltages. Do not attempt
any service or adjustment unless another person capable of rendering rst aid and resuscitation is present.
Do not insert any object into an instrument’s ventilation openings or other openings.
Hazardous voltages may be present in unexpected locations in circuitry being tested when a fault condition in the circuit
exists.
Fuse replacement must be done by qualied service-trained maintenance personnel who are aware of the instrument’s fuse
requirements and safe replacement procedures. Disconnect the instrument from the power line before replacing fuses.
Replace fuses only with new fuses of the fuse types, voltage ratings, and current ratings specied in this manual or on
the back of the instrument. Failure to do so may damage the instrument, lead to a safety hazard, or cause a re. Failure
to use the specied fuses will void the warranty.

5
Servicing
Do not substitute parts that are not approved by B&K Precision or modify this instrument. Return the instrument to
B&K Precision for service and repair to ensure that safety and performance features are maintained.
For continued safe use of the instrument
• Do not place heavy objects on the instrument.
• Do not obstruct cooling air ow to the instrument.
• Do not place a hot soldering iron on the instrument.
• Do not pull the instrument with the power cord, connected probe, or connected test lead.
• Do not move the instrument when a probe is connected to a circuit being tested.
Compliance Statements
Complies with the essential requirements of the following applicable European Directives, and carries the CE marking
accordingly:
• Electromagnetic Compatibility (EMC) Directive 2014/30/EU
• Low-Voltage Directive (Safety) 2014/35/EU
Conforms with the following product standards:
EMC Standard
IEC 61326-1:2012/ EN 61326-1:2013123
Reference Standards
CISPR 11:2009+A1:2010/ EN 55011:2009+A1:2010 (Group 1, Class A)
IEC 61000-4-2:2008/ EN 61000-4-2:2009
IEC 61000-4-3:2006+A1:2007+A2:2010/ EN 61000-4-3:2006+A1:2008+A2:2010
IEC 61000-4-4:2004+A1:2010/ EN 61000-4-4:2004+A1:2010
IEC 61000-4-5:2005/ EN 61000-4-5:2006
IEC 61000-4-6:2008/ EN 61000-4-6:2009
IEC 61000-4-11:2004/ EN 61000-4-11:2004
1. The product is intended for use in non-residential/non-domestic environments. Use of the product in residential/do-
mestic environments may cause electromagnetic interference.
2. Connection of the instrument to a test object may produce radiations beyond the specied limit.
3. Use high-performance shielded interface cable to ensure conformity with the EMC standards listed above.
Safety Standard
IEC 61010-1:2010/ EN 61010-1:2010

6
Waste Electrical and Electronic Equipment (WEEE) Directive
Disposal of Old Electrical & Electronic Equipment (Applicable in the European Union and other European
countries with separate collection systems)
This product is subject to Directive 2002/96/EC of the European Parliament
and the Council of the European Union on waste electrical and electronic equipment
(WEEE), and in jurisdictions adopting that Directive, is marked as being put on the
market after August 13, 2005, and should not be disposed of as unsorted municipal
waste. Please utilize your local WEEE collection facilities in the disposition of this
product and otherwise observe all applicable requirements.
Safety Symbols
Symbol Description
indicates a hazardous situation which, if not avoided, will result in death or serious injury.
indicates a hazardous situation which, if not avoided, could result in death or serious injury
indicates a hazardous situation which, if not avoided, will result in minor or moderate injury
Refer to the text near the symbol.
Electric Shock hazard
Alternating current (AC)
Chassis ground
Earth ground
This is the In position of the power switch when instrument is ON.
This is the Out position of the power switch when instrument is OFF.
is used to address practices not related to physical injury.

Contents
1 Introduction 9
1.1 Product Overview 9
1.2 Description 9
1.3 Features 10
1.4 Dimensions 10
1.5 Front Panel 11
1.6 Rear Panel 12
1.7 Protection Functions 13
1.7.1 Overvoltage Protection (OVP) 13
1.7.2 Operations to Clear the OVP State 13
1.7.3 Overcurrent Protection (OCP) 13
1.7.4 Overpower Protection (OPP) 14
1.7.5 Overtemperature Protection (OTP) 14
1.7.6 Reverse Voltage Protection (LRV/RRV) 15
1.8 Menu List 15
2 Installation 19
2.1 Inspection 19
2.2 Cleaning 19
2.3 Installing Modules 19
2.4 Channel Number 22
2.5 Location 23
2.6 Input Voltage Selection 23
2.7 Turn-On Checkout 24
2.8 If the Electronic Load Does Not Turn On. 24
3 Load Connection 26
3.1 Parallel Connection 27
3.2 Mainframe 8-pin Control Connector 28
3.3 External Trigger Connections 29
3.3.1 Trigger Modes 29
3.4 External ON/OFF Control Connection 30
3.5 Mainframe Extension Connection 30
3.6 PC Control Connection 31
4 Operations 32
4.1 Operation Modes 32
4.1.1 Constant Current (CC) Mode 32
4.1.2 Constant Voltage (CV) Mode 34
4.1.3 Constant Resistance (CR) Mode 35
4.1.4 Constant Power (CP) Mode 36
4.1.5 Constant Impedance (CZ) Mode 37
4.1.5.1 Setting CV,CC,CR, CW,CZ Mode 38
4.2 Local Operations 39
4.2.1 Mainframe Panel 39
4.2.2 Module Panel 41
4.2.3 Module Panel Lock 42
4.3 Switching Channels 42
4.4 Channel Synchronization 42
4.5 Module VFD Indicator Function Description 43
4.6 Transient Operation 44
4.6.1 Continuous 44
4.6.2 Pulse 45

8
4.6.3 Toggle 45
4.6.4 Setting Up A/B Transient Operation 46
4.7 List Operation 48
4.7.1 Setting Up List Operation Mode 48
4.8 Trigger Operation 51
4.8.1 Manual Trigger 51
4.8.2 External Trigger Signal(TTL level) 51
4.8.3 Hold Trigger 51
4.8.4 Bust Trigger 51
4.8.5 Timer Trigger 51
4.9 Short Operation 51
4.10 Input On/O Operation 51
4.11 Von Operation 52
4.12 Save and Recall Operation 54
4.13 Module Controlling Link 54
4.13.1 Voltage Failure Indication 55
4.13.2 Current Monitoring 55
4.13.3 Digital I/O 55
4.13.4 Remote Sense Function 55
4.13.5 External Analog Control 55
4.14 Automatic Test 56
4.15 Conguring Pass/Fail Paramters 56
4.15.1 Conguring Instrument Settings 56
4.15.2 Recall Test Files 59
4.16 Remote Operation 60
4.16.1 USB Interface 61
4.16.2 Ethernet Interface 61
4.16.3 GPIB Interface 61
5 Specications 64
6 Service Information 66
7 LIMITED THREE-YEAR WARRANTY 67

Introduction
1.1 Product Overview
This section describes the main features and menus of the MDL4U Series DC Electronic Load. The MDL4U Series is
comprised of two parts, mainframes and modules. The mainframes mentioned are the MDL4U001 mainframe and the
MDL4U002 mainframe extension. Modules in this series include the MDL4U200, MDL4U252, MDL4U302, MDL4U305,
MDL4U400, MDL4U505, and MDL4U600. Unless otherwise noted, this document will refer to all of these instruments as
“electronic load”. The range of each module’s specic voltage, current, and power is listed in the Specications section.
1.2 Description
Front View Rear View
Figure 1.1 MDL4U 001 and 002 Populated
The MDL4U Series is a multi-channel modular programmable electronic load system. Seven dierent modules of pro-
grammable DC loads ranging in power from 200 W to 600 W provide users the exibility to test a wide range of power
sources from multi-output DC power supplies to batteries, fuel cells, and photovoltaic arrays.
Up to four modules can be installed into the MDL4U001 mainframe to support up to a total of 8 channels. Adding the
MDL4U002 mainframe extension will enable the system to support four additional module slots for a maximum of 16
channels. The electronic load is congured by installing user-selectable modules into the mainframe and operated using
the front panel keypad and rotary knob. It can also be controlled remotely via USB, RS-232, LAN, or GPIB interface.
The electronic load modules all have similar functions, but may dier in range of input voltage, current, and power. The
high resolution voltage and current measurement system provides both accuracy and convenience.
The electronic load can be used in one of ve dierent operation modes: constant voltage (CV), constant current (CC),
constant resistance (CR), constant power (CW), or constant impedance (CZ). All panel operation and programming
functions are carried out on the MDL4U001 mainframe panel. A wide range of dynamic loading applications can be
simulated through user-programmable slew rates, load levels, duration, and conducting voltage.
Model MDL4U200 MDL4U252 MDL4U302 MDL4U305 MDL4U400 MDL4U505 MDL4U600
Power 200 W *250 W/50W *300 W/300 W 300 W 400 W 500 W 600 W
Operating Voltage 80 V 80 V 80 V 500 V 80 V 500 V 80 V
Rated Current 40 A 20 A 45 A 20 A 60 A 30 A 120 A
No. of Channels 1 2 2 1 1 1 1
Table 1.1 MDL4U Modules

Introduction 10
* The MDL4U252 and MDL4U302 are dual-channel load modules. The MDL4U252 can allocate up to 250 W to either
channel up to 300 W total. (e.g. 250 W/50 W, 150 W/150 W). Similarly, the MDL4U302 can allocate 300 W to either
channel up to 600 W total (e.g. 300 W/300 W)
1.3 Features
• Power range up to 2400 W
• Voltage range up to 500 V
• Current range up to 120 A
• CC/CV/CR/CW/CZ operating modes
• Removable modules for easy system congurability
• Support for up to 16 channels using dual channel modules with mainframe extension
• Operate identical modules in parallel mode for high current applications
• Synchronous load on/o function
• Standard LAN, GPIB, USB, and RS232 interfaces with USBTMC/SCPI protocol support
• Analog current control and monitoring
• Transient mode up to 25 kHz
• List mode (sequence mode) - minimum 20 s step width with 84 user programmable steps
• Adjustable slew rate in CC mode
• 16-bit voltage and current measurement system providing high resolution of 0.1 mV and 0.01 mA
• Automatic test function
• 101 memory locations to save/recall setting parameters
• Remote sense
• OVP/OCP/OPP/OTP and reverse voltage protection
• Rack-mount brackets with handles included
1.4 Dimensions
The MDL4U’s dimensions are as follow:
MDL4U Model : 001 002 200, 252, 302, 305, 400, 505, 600
Type Mainframe Mainframe extendsion Module
Dimensions
(W x H x D)
17.3” x 7” x 21.6”
(440 x 177.3 x 549 mm)
17.3” x 7” x 21.6”
(440 x 177.3 x 549 mm)
3.2” x 6.7” x 22.6”
(82 x 170.5 x 573 mm)
Weight 34 lbs (15.4 kg) 34 lbs (15.4 kg) 11 lbs (5 kg)
Table 1.2 MDL4U Modules

Introduction 11
1.5 Front Panel
Figure 1.2 Front Panel
Item Name Description
1 VFD Display Displays electronic load information.
2 Module Panel Keys Controls module functions. Refer to Module section for more details.
3 Rotary Knob Used to change parameters.
4 Mainframe Function Keys Controls each channel’s operating status. Refer to Mainframe for more details.
5 Mainframe Numeric Keypad Used to enter precise values when adjusting parameters.
6 Power Switch Turns the system ON or OFF.
7 Mainframe Index Channel index indicating the corresponding slot’s channels.
8 Modules Select and add any combination of 4 modules including dual-channel modules .
9 Rack-Mount Ear Ears that protrude out on each side to be fastened to the frame with screws.
Table 1.3 Front Panel

Introduction 12
1.6 Rear Panel
Figure 1.3 Rear Panel
Item Name Description
1 GPIB Interface Connect a GPIB cable to remotely control the unit
2 Module Input Terminal Load input termianls.
3 Current Monitoring Connect an external voltmeter or oscilloscope to display the input’s current.
4 Remote Sense/External Control Remote Sense:Eliminates the eect of voltage drop in the load leads.
External Control Contol the module using an external analog source.
5 Digital I/O and VF Output Digital I/O: Universal output terminal use to control an external instrumnet.
VF Output: Voltage fault indication terminal.
6 Extended Mainframe Connects MDL4U001 to MDL4U002 to expand channel capacity to 16 channels.
7AC Power Input
& Fuse Box Houses the fuse and the AC input.
8 USB Interface Connect a USB type B to type A to remotely control the unit.
9 Line Voltage Selection Select 110/220V±10%AC input.
10 Trigger I/O &
Load On/O Terminals Refer to section 8-pin Control Connector for more details.
11 LAN Interface Connect a Cat 5/6 Ethernet straight-through patch cable to remotely control
the unit.
12 RS232 Interface Connect a cable with a two COM interface (DB9) to remotely control the unit.
13 Not Used For factory use only.
Table 1.4 Rear Panel

Introduction 13
1.7 Protection Functions
The electronic load has the following protection functions: Overvoltage protection (OVP), overcurrent protection (OCP),
overpower protection (OPP), overtemperature protection (OTP), and local and remote reverse voltage protection (LRV/RRV).
The mainframe will act appropriately once any of the above protections are active. You can press any button on the front
panel to restore the protection function. For example, if the electronic load triggers the overtemperature protection, the
buzzer will alarm, the input will automatically turn o, and the mainframe VFD will display OTP.
1.7.1 Overvoltage Protection (OVP)
If the OVP circuit has triggered, input will turn o, buzzer alarm will go o, and the status register’s OV and VF bit will
be set. The mainframe will display OVP and the condition will remain until they are reset. Once overvoltage protection
occurs, the 8-pin connector’s VF pin on the rear panel will output TTL high voltage level. You can control the output
state of the power supply under test via this pin (see Figure 4.16).
1.7.2 Operations to Clear the OVP State
Check whether the input voltage is within the electronic load’s rated voltage or the programmed protection voltage ranges.
If it is outside the range, please disconnect the device under test. Then press any key on the front panel or remotely send
SCPI command PROTection:CLEar. The OVP displayed on the front panel will turn o and the electronic load exits
OVP protection state.
1.7.3 Overcurrent Protection (OCP)
The electronic load includes both hardware and software overcurrent protection features.
Hardware OCP - The electronic load’s maximum input current will be limited to approximately 110% of the current range.
Once the hardware OCP is triggered, the status register’s OC bit will be set. When the hardware OCP is removed, the
status register’s OC bit will be reset. Hardware overcurrent protection will not aect the electronic load’s on/o state.
To set the electronic load’s OCP value:
1. Power on the electronic load. Self-test
2. Press + to enter Conguration menu.
3. Press key to select PProtect and press Enter to go into protection menu.
4. Press key to select Alimit State and press Enter.
– Select On and press Enter to conrm.
5. Press key to select Alimit Point and press Enter.
– Input OCP current value and press Enter to conrm.
6. Press key to select Alimit Delay and press Enter.
– Input delay time before alarm and press Enter to conrm.
7. Press Esc key to exit menus
If the electronic load’s current value is above the set overcurrent protection value, the electronic load will automatically
turn o and the VFD will display OCP. At the same time, the OC and PS bits in the status register will be set and remain
until they are reset.

Introduction 14
Operations To Clear the OCP State
Check whether the input current is within the electronic load’s rated current or the programmed protection current ranges.
If it is outside the range, disconnect the device under test. Then press any key on the front panel or remotely send SCPI
command PROTection:CLEar. The OCP displayed on the front panel will turn o and the load exits OCP protection
state.
1.7.4 Overpower Protection (OPP)
The electronic load includes both hardware and software OPP features.
Hardware OPP – In the event that the electronic load’s input power exceeds the set power protection limit, the hardware
OPP will limit the power. Once the hardware OPP is triggered, the status register’s OP bit will be set. When the
hardware OPP is removed, the status register’s OP bit will be reset. Hardware overpower protection will not turn the
electronic load’s input o.
To set the electronic load’s OPP value:
1. Power on the electronic load. Self-test
2. Press + to enter Conguration menu.
3. Press key to select PProtect and press Enter to go into protection menu.
4. Press key to select Plimit Point and press Enter.
– Input OPP power value and press Enter to conrm.
5. Press key to select Plimit Delay and press Enter.
– Input delay time before alarm and press Enter to conrm.
6. Press Esc key to exit menus
If the electronic load’s power value is above the set overpower protection value, the electronic load will automatically turn
o and the VFD will display OPP. At the same time, the OP and PS bits in the status register will be set and remain
until they are reset.
Operations to Clear the OPP State
Check whether the input power is within the rated power range or the programmed protection ranges. If it is out-
side the range, disconnect the device under test. Then press any key on the front panel or remotely send command
PROTection:CLEar. The OPP displayed on the front panel will turn o and the electronic load exits OPP protection
state.
1.7.5 Overtemperature Protection (OTP)
Each module has an overtemperature protection circuit, which will turn o the input if the internal temperature exceeds
safe limits. When the electronic load’s internal circuit temperature is over 85°C, the load will enable OTP. Input will
automatically be turned o and the VFD will display OTP. At the same time the OT and PS bits in the status register
will be set and remain until they are reset.
Operations to Clear the OTP State
When the electronic load temperature has dropped below the protection point, press any key on the front panel or
remotely send command PROTection:CLEar. The OTP displayed on the front panel will turn o and the electronic load
exits OTP protection state.

Introduction 15
1.7.6 Reverse Voltage Protection (LRV/RRV)
This function protects the electronic load in case the input DC voltage lines are connected with the wrong polarity. When
a reverse voltage (LRV – local reverse voltage, RRV – remote reverse voltage) connection condition is detected, the input
will immediately turn o, the buzzer will alarm the user, and the status register’s reverse voltage (LRV/RRV) and VF
bits will be set. The mainframe will display LRV/RRV until they are reset.
In this condition, the 8-pin connector’s VF pin will output a high level. You can disconnect the power supply via this
signal (see Figure 4.16).
Operations to Clear the Reverse Voltage State
Check whether the connection is reversed. If so, disconnect the device to be measured to clear the reverse voltage state.
1.8 Menu List
The following menus can be viewed on the VFD display. Use the keys to scroll through the menu list. Press the
Enter key to enter the selected menu function. Use the keys to scroll through the VFD screen and press Enter
key to enter its submenu. Press Esc to go back to the previous menu selection. Pressing number keys can directly select
a channel.
Press the the key to enter the Setup menu.
Setup
MODE Select working mode
CONST CURRENT Load works in CC mode
CONST VOLTAGE Load works in CV mode
CONST RESISTANCE Load works in CR mode
CONST POWER Load works in CW mode
CONST IMPEDANCE Load works in CZ mode
CC/CV RANGE Switch the range
HIGH RANGE Set high range
LOW RANGE Set low range
I / V / R / W SET Set the working current/voltage/resistance/power value
Vmax/Amax Set up the maximum voltage/current limit for Automatic test mode
Vmin/Amin Set up the minimum voltage/current limit for Automatic test mode
∫= 2.500A/us Set the rising slew rate (only in CC mode)
∫= 2.500A/us Set the falling slew rate (only in CC mode)
TRAN A = 0.00A Set up level A value
Ta = 0.0005S Set up level A width
TRAN B = 0.00A Set up level B value
Tb = 0.0005S Set up level B width
T MODE Set up the transient mode
CONTINUOUS Continuous
PULSE Pulse mode
TOGGLE Toggle mode
RLC R = 7500.0Ω Set up the resistance value
RLC L = 0uH Set up the inductance value
RLC C = 10uF Set up the capacitance value
EXIT Exit the setup menu
Table 1.5 Setup Menu

Introduction 16
System Menu
Press + to enter the System menu.
MENU
INITIALIZE
INITIALIZE
DEFAULT SET Resume all conguration to default settings
POWER ON SET
RST (DEFAULT) Set the load’s input state to default at power on
SAV0 Set the load’s input state to SAV0 at power on
BUZZER SET Set up the buzzer state
ON Enable the function
OFF (DEFAULT) Disable the function
LOAD ON KNOB Module knob mode setting
UPDATE (DEF) Real-time update
OLD No update (when turning load ON/OFF, original value before
use of rotary knob will be set)
TRIGGER SOUR. Set up the trigger mode
MANUAL (DEF) Manual trigger
EXTERNAL External signal trigger mode
HOLD Hold trigger mode
BUS Bus trigger mode
TIMER Timer trigger
TRIGGER TIMER Trigger timer setting
TRIGGER TIMER SET Set the time of the trigger timer
COMMUNICATION Select the interface for remote communication
RS232 (DEF)
USBTMC-USB488
GPIB
ETHERNET
RS232 SET
BAUDRATE SET Set up the communication baud rate
4800 (DEFAULT)
9600
19200
38400
57600
115200
PARITY SET Set up the communication parity
NONE (DEFAULT)
ODD
EVEN
HANDSHAKE SET Select the handshake protocol
NONE (DEFAULT)
CTS/RTS
XON/XOFF
Table 1.6 System Menu

Introduction 17
System Menu Cont...
GPIB ADDRESS GPIB address setting
GPIB ADDRESS SET Set up communication address
ETHERNET SET Ethernet settings
GATEWAY SET Gateway setting
IP SET IP setting
MASK SET Mask setting
PORT SET Port setting
EXIT
EXPAND MODULE Module expansion
ON Enable the function
OFF (DEFAULT) Disable the function
LANGUAGE SET Communication protocol
SCPI (DEFAULT) SCPI protocol
EXTEND TABLE Expand SCPI protocol, compatible with others
ABOUT Mainframe production information
MDL### Mainframe production model number
SN: ########## Mainframe production serial number
VER: 1.43 Mainframe software version
EXIT
Table 1.7 System Menu Cont...
Conguration Menu
Press + to enter the Conguration menu.
Conguration Menu
SYNC ON SET Setup Synchronization ON / OFF function
ON (DEFAULT) Turn on synchronization function
OFF Turn o synchronization function
VON
VON POINT Set the load’s Von point
VON LATCH Von latch state
ON (DEFAULT) Turn on Von latch
OFF Turn o Von latch
EXIT Exit the menu
AVERAGE COUNT Average count setting 2^X (adjustable from 2^2 to 2^16)
V AUTORANGE Auto switching voltage range
ON (DEFAULT) Enable this function
OFF Disable this function
Table 1.8 Conguration Menu

Introduction 18
Conguration Menu Cont...
ALIMIT POINT Set up software current protection value
ALIMIT DELAY Set up software current protection delay
PLIMIT POINT Set up software power protection value
PLIMIT DELAY Set up software power protection delay
ON TIMER STATE Set up LOAD ON timer state
ON TIMER SET Set up LOAD ON timer time
EXIT Exit the menu
LIST
FUNCTION MODE Select mode
FIXED Choose xed operation mode
LIST Choose list operation mode
RECALL LIST Recall list operation le
EDIT LIST Edit list operation le
HIGH RANGE Edit high range of list operation
LOW RANGE Edit low range of list operation
EXT. CTRL SET External analog control function
ON Turn on external analog control function
OFF (DEFAULT) Turn o external analog control function
REM SENSE SET Remote sense function
ON Enable remote sense function
OFF (DEFAULT) Disable remote sense function
ABOUT Module production information
MDL### Channel production model
SN:######## Channel production serial number
VER: 1.35 Channel software version
EXIT Exit the menu
Table 1.9 Conguration Menu Cont...
Automatic Test Menu
Press + to enter the Automatic Test menu.
Automatic Test Menu
PROGRAM
RUN PROGRAM Run the testing le
RECALL PROG Recall the testing le
EDIT PROGRAM Edit the testing le
EXIT
Table 1.10 Automatic Test Menu

Installation
2.1 Inspection
This instrument was carefully inspected before shipment. Upon receipt, inspect the instrument for damage that might
have occurred during transit. If any sign of damage is found, please notify your B&K Precision distributor.
The following standard and optional accessories are provided with each mainframe or module.
Mainframes include:
• Power cord
• USB cable (MDL4U001 only)
• Mainframe extension cable accessory (MDL4U002 only)
Modules include:
• Certicate of calibration
Note:
Ensure the presence of all the items above. Notify your B&K Precision distributor if anything is missing.
2.2 Cleaning
Use a dry cloth or one slightly dampened with water to clean the external case parts. Do not attempt to clean internally.
Warning:
To prevent electric shock, please unplug the power cord connected to the unit before cleaning.
2.3 Installing Modules
Caution:
Static electricity may damage load modules. Please install modules according to
standard electrostatic prevention. Avoid touching joints and circuit boards.
Any combination of modules up to 2400 W total in the MDL4U001 mainframe in any order. This also applies to the
MDL4U002 mainframe extension, allowing a maximum of 4800 W total when connecting the MDL4U001 and MDL4U002
together. The procedure of installing modules to the mainframe extension is the same as that of the MDL4U001
mainframe.

Installation 20
Installation Procedure
1. Turn the mainframe o and disconnect the power cord.
2. Remove the plastic cover with a at-blade screwdriver.
Figure 2.1 Removing Covers
3. Loosen the screws on the rear panel and remove the metal place holders.
Figure 2.2 Removing Rear Cover Screws