The following safety precautions apply to both operating and maintenance personnel and
must be observed during all phases of operation, service, and repair of this instrument. Before
applying power, follow the installation instructions and become familiar with the operating
instructions for this instrument.
GROUND THE INSTRUMENT
To minimize shock hazard, the instrument chassis and cabinet must be connected to
an electrical ground. This instrument is grounded through the ground conductor of
the supplied, three-conductor ac power cable. The power cable must be plugged
into an approved three-conductor electrical outlet. Do not alter the ground
connection. Without the protective ground connection, all accessible conductive
parts (including control knobs) can render an electric shock. The power jack and
mating plug of the power cable meet IEC safety standards.
DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE
Do not operate the instrument in the presence of flammable gases or fumes.
Operation of any electrical instrument in such an environment constitutes a definite
safety hazard.
KEEP AWAY FROM LIVE CIRCUITS
Instrument covers must not be removed by operating personnel. Component
replacement and internal adjustments must be made by qualified maintenance
personnel. Disconnect the power cord before removing the instrument covers and
replacing components. Under certain conditions, even with the power cable
removed, dangerous voltages may exist. To avoid injuries, always disconnect power
and discharge circuits before touching them.
DO NOT SERVICE OR ADJUST ALONE
Do not attempt any internal service or adjustment unless another person, capable of
rendering first aid and resuscitation, is present.
DO NOT SUBSTITUTE PARTS OR MODIFY THE INSTRUMENT
Do not install substitute parts or perform any unauthorized modifications to this
instrument. Return the instrument to B&K Precision for service and repair to ensure
that safety features are maintained.
Do not alter the ground connection. Without the protective ground
connection, all accessible conductive parts (including control knobs)
can render an electric shock. The power jack and mating plug of the
power cable meet IEC safety standards.
WARNING:
To avoid electrical shock hazard, disconnect power cord before
removing covers. Refer servicing to qualified personnel.
CAUTION:
Before connecting the line cord to the AC mains, check the rear panel
AC line voltage indicator. Applying a line voltage other than the
indicated voltage can destroy the AC line fuses. For continued fire
protection, replace fuses only with those of the specified voltage and
current ratings.
CAUTION:
This product uses components which can be damaged by electrostatic discharge (ESD). To avoid damage, be sure to follow proper
procedures for handling, storing and transporting parts and
subassemblies which contain ESD-sensitive components.
WARNINGS AND CAUTIONS
WARNING and CAUTION statements, such as the following examples, denote a
hazard and appear throughout this manual. Follow all instructions contained in
these statements.
A WARNING statement calls attention to an operating procedure, practice, or
condition, which, if not followed correctly, could result in injury or death to
personnel.
A CAUTION statement calls attention to an operating procedure, practice, or
condition, which, if not followed correctly, could result in damage to or destruction
of parts or the entire product.
SAFETY SYMBOLS
This symbol on an instrument indicates that the user should refer to the
operating instructions located in the manual.
Certification
We certify that this product met its published specifications at time of shipment from the
B&K Precision models 1900B, 1901B, and 1902B are laboratory grade switching mode
DC power supplies with high current output in a small form factor and lightweight
package. The 1900B Series provide different configurations of high output voltage or
high output current and make setting voltage and current levels fast and precise
through its dual action, course/fine rotary encoder control. In addition to its constant
voltage (CV) and constant current (CC) modes, the high efficiency DC power supply
offers a unique solution with its preset and analog remote control modes. Save up to
three different presets of voltage and current values for quick recall. The analog
remote control function allows the output power, voltage, and current to be adjusted
without touching the front panel of the power supply. A remote sense terminal
(model 1900B only) is also available for use to compensate for voltage drop across
load leads. These features make the 1900B Series suitable for a wide range of
applications including production testing, telecommunications, R&D, service, and
university labs.
Features
Automatic CV/CC crossover operation
Up to 60 A output current
Lightweight and compact
Rotary encoder control for precise voltage and current setting
3 user-defined voltage and current presets
Analog remote control function
Remote sense terminal (model 1900B only)
USB interface
Front panel auxiliary output
Overvoltage, overtemperature, and overload protection
The LED and other indicators on the front panel will be turned on. When the cooling
fan is being checked, a loud fan noise can be heard.
After the self checks, the CV, V, and A LED indicators are lit up displaying voltage and
0.0 current. To find out about the set CC current level, just turn the current control
knob one click in either direction. The current display returns to 0.0 after a few
seconds.
4.1.3 Control Knobs
The rotary encoder control knobs have fine and coarse tuning with clicking
movement.
Push the knobs to toggle between coarse and fine tuning. You will notice the subtle
change in brightness of LED.
Adjust the knobs to your desired values through coarse and fine tuning. The display
will resume its normal brightness after a few seconds to confirm your adjustment.
The power supply will automatically zero the current meter offset when powered up.
In case it is needed to reset the current meter to zero during a test, you can manually
reset it to zero. This function can be used to zero meter readings < 1 A.
1. Press and hold the Voltage Control Knob for 30 s to enter Menu mode.
2. Rotate the Current Control Knob until the current meter displays “YES”.
3. Then press the Current Control Knob once to confirm. The “YES” will light up
after successfully zeroing current meter offset.
4. Finally, press the Voltage Control Knob to exit.
The power supply has a main output in the rear and an auxiliary output in the front
that can be used separately or together.
The main and auxiliary output both share the same voltage and current control knobs
and will output the same voltage and current up to the maximum output ratings of
the power supply and terminals. When using both the main and auxiliary outputs
together, the power supply will automatically total the currents supplied to both
terminals up to the current limit of the power supply and show the total current on
the display.
For example, setting the voltage and current outputs for model 1900B (1-16 V, 0-60
A) to 16 V and 60 A would output 16 V at both main and auxiliary terminals and allow
you to draw up to a total of 60 A between the two terminals. If there is a 5 A load at
the auxiliary terminal, the most current you can draw from the main output is 55 A.
If the power supply reaches its set current limit at any time, the power supply will go
into CC mode and the loads together will draw up to the total value of the current
limit. Distribution of current between the main and auxiliary terminals will vary
depending on the loads.
Note: 1900B: Total rated current (Aux. + Main) is 60 A
1901B: Total rated current (Aux. + Main) is 30 A
1902B: Total rated current (Aux. + Main) is 15 A
4.2 Control Modes
There are four different control modes for the power supply:
To select a mode, slide the Mode Selection Switch on the rear of the unit.
Figure 3 – Mode Selection Switch
Note: The power supply is factory preset to Normal Mode with maximum current
level.
4.2.1 Normal Mode
This is the factory preset mode and the power supply output voltage and current are
controlled by the dual action dial knobs.
Push the knobs to toggle the coarse and fine tuning. You will notice the subtle
change in brightness of LED.
Adjust the knobs to your desired values through coarse and fine tuning. To check the
preset current level, turn the Current Knob lightly in any direction.
The display will resume its normal brightness after a few seconds to confirm your
adjustment.
4.2.2 Preset Mode
In this mode, the Rear Control light is ON to indicate panel voltage and current
controls are deactivated.
There are three presets P1/P2/P3 on the Recall Selection Switch. The factory preset
values are shown in Table 3.
Figure 3 shows typical connection between power supply and device for remote
sense operation.
Figure 3 - Remote Sense Connection
The remote sense wire gauge should be at least 22AWG.
4.3.2 Disconnection
WARNING: Wrong disconnect sequence will damage the power supply.
1. Disconnect the remote sense connections.
2. Disconnect the power connections between the power supply and
equipment.
5 Remote Control
There are two methods to remotely control voltage and current.
Note: Both methods require the remote control connector plug to be set up in order
for analog remote control mode to be functional; otherwise the unit will be in CC
mode all the time.
Table 4 – Remote Connector Plug Pin Assignment for External Variable Voltage Sources
A variable external DC voltage source of 0 – 5 V is fed into the analog remote control
terminal to adjust the output voltage level of both Main and Auxiliary output.
WARNING: Do not input higher than 5 V, otherwise the overvoltage protection
(OVP) will be triggered.
1. Make sure the load is disconnected and the power supply is OFF.
2. Connect pin 2 to positive polarity of first external voltage source and pin 4 to
negative polarity of first external voltage source.
3. Connect pin 3 to positive polarity of second external voltage source and pin
4 to negative polarity of second external voltage source.
4. Turn the remote control ON/OFF switch to ON position.
5. Switch on the power supply.
6. Check the output voltage range of the power supply by varying the external
voltage source for voltage adjustment from 0 to 5 V.
7. Short circuit the main output with a 12AWG wire and check the display for
CC setting by varying the external voltage source for current adjustment
from 0 to 5 V.
The power supply provides a USB interface for remote control via PC. Please see
programming manual for more information on the PC interface control setup,
software, and remote commands.
Note: The power supply must be in Normal Mode and operated as a standalone
equipment (not connected in series or parallel with multiple supplies) for PC
interface control.
This unit has a built-in tracking overvoltage protection feature. In the event of the
output voltage becoming greater than the set value (see specified range from
Specifications section), protection will be triggered and the output power will be cut
off. OVP warning will appear as shown below.
Figure 8 - Overvoltage Protection
To reset the warning, switch off the unit and remove all connected devices. Switch
the unit back on again and it should resume normal operation. If the problem
persists, please contact B&K Precision.
6.2 OTP: Overtemperature Protection
There is a temperature sensor inside the unit to monitor and prevent the unit from
getting too hot. When OTP is triggered, there is no output and the following warning
will appear on the LED display.
When you get this warning, switch off the unit and remove all loading. Check your
load and output settings and allow the unit to cool down for at least 30 minutes.
Check if any of the ventilation is blocked and make sure there is enough clearance
around the power supply. Listen carefully for the fan noise from the cooling fan when
you turn on the unit again. If you cannot hear this routine self-test fan noise upon
power on, the fan has failed and the power supply should not be used. In this case,
please contact B&K Precision.
6.3 OLP: Overload Protection
Normally the overload protection is sustained by the CC constant current mode.
When the CC mode fails and goes undetected, it may cause serious damage to your
test piece or load. The OLP is to minimize the extent of damage to your loads as
power supplies will fail at some point in time. Switch off your power supply as soon
as you see this warning as shown in Figure 10.
To reset this warning, switch off the unit and remove all connected devices. Switch
the unit back on again and double check with caution. If the problem persists, please
contact B&K Precision.
6.4 Upper Voltage Limit (UVL) and Upper Current Limit (UCL)
The power supply has upper voltage and upper current limit settings to prevent
accidental changes to the output settings. These values can only be set through PC
software.
If voltage is set beyond the power supply’s upper voltage limit when increasing the
output voltage setting, the voltage display will show the following:
If current is set beyond the power supply’s upper current limit when increasing the
output current setting, the current display will show the following:
Figure 12 – Upper Current Limit
6.5 Fuse Replacement
If the fuse blows, the CV or CC indicators will not light and the power supply will not
operate. The fuse should not normally open unless a problem has developed in the
unit. Try to determine and correct the cause of the blown fuse, then replace only
with a fuse of the correct rating as listed below. The fuse is located on the rear panel
(see Figure 2). Pull fuse compartment out with a flathead screwdriver and replace
fuse in holder.
Thermostatically controlled fan from zero to full speed
Protections
Overload, Short Circuit by Constant Current,
Overvoltage, Overtemperature
Special Features
3 User-Defined Voltage and Current Presets, Analog
Remote Control, Remote Sense (model 1900B only)
Operating Temperature
32 °F to 104 °F (0 °C to 40 °C) ≤ 80% R.H.
Storage Temperature
5 °F to 158 °F (-15 °C to 70 °C) ≤ 85% R.H.
Dimensions (WxHxD)
7.9” x 3.5” x 10.8” (200 x 90 x 275 mm)
Weight
7 lbs (3.2 kg)
Supplied Accessories
Power cord, instruction manual, USB cable, remote
control connector
Note: All specifications apply to the unit after a temperature stabilization time of 15
minutes over an ambient temperature range of 23 °C ± 5 °C. Specifications are
subject to change without notice.
*For 220 V version, please request -220V model on order: 1900B-220V, 1901B-220V,
or 1902B-220V.