B&K Precision 1739 User Manual
Model 1739
DC Power Supply with 0.1mA Settable
Resolution
INSTRUCTION MANUAL
1 Safety Summary
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.
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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.
WARNING:
WARNING:
CAUTION:
CAUTION:
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.
To avoid electrical shock hazard, disconnect power cord before
removing covers. Refer servicing to qualified personnel.
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.
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.
SAFETY SYMBOLS
Connect to safety earth ground using the wire recommended in the user
manual.
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
factory.
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Compliance Statements
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.
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Contents
Safety Summary ............................................................. 1
1
2 Introduction .................................................................... 5
3 Quick Reference ............................................................. 7
3.1 Front Panel ......................................................................................... 7
3.2 Rear Panel .......................................................................................... 8
4 Operating Instructi ons .................................................. 9
4.1 Instrument Hook-Up ........................................................................ 10
4.2 Typical Constant Voltage Operation ................................................ 12
4.3 Setting Current Limit ....................................................................... 13
4.4 Typical Constant Current Operation ................................................ 14
4.5 Constant Voltage/Constant Current Characteristic .......................... 15
4.6 Saving the Power Supply’s Current State ........................................ 16
4.7 Connecting Two Power Supplies in Series ...................................... 16
4.8 Connecting Two Power Supplies in Parallel .................................... 17
5 RS232 Inter face ............................................................ 18
5.1 RS232 Configuration Overview ...................................................... 19
5.2 RS232 Commands ........................................................................... 19
6 Maintenance ................................................................. 21
6.1 Fuse Replacement ............................................................................ 21
6.2 Adjustments ..................................................................................... 21
6.3 Calibration ....................................................................................... 22
6.4 Instrument Repair Service ............................................................... 27
7 Error Messages ............................................................. 27
7.1 Self-Test Errors ................................................................................ 27
7.2 Calibration Errors ............................................................................ 27
7.3 Command Errors .............................................................................. 29
8 Specifications ................................................................ 29
9 Service Information ..................................................... 31
10 Limited Three-Year Warranty ................................... 32
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2 Introduction
Description
The B&K Precision model 1739 is a high quality, low current DC power source.
This power supply provides 0-30 volts dc output, adjustable with both coarse and
fine voltage controls for precise settability. The current output is 0-1 amps,
adjustable with both coarse and fine current controls. Two large LED meters
continuously monitor the output voltage and current. The VOLTAGE meter is
green, while the CURRENT meter is red.
The power supply can be programmed locally from the front panel or remotely
through the RS-232 interface. Two large LED meters continuously monitor the
output voltage and current. The voltage meter is green, while the current meter
is red. The power supply can be operated locally from the front panel or
remotely through the RS-232 interface.
The 1739 exhibits excellent regulation and low ripple characteristics. The circuit
design incorporates a pre-regulator, which greatly reduces internal power
dissipation at low output voltages. The styling is both attractive and functional.
The mechanical configuration conserves bench space and allows for easy
portability.
This instrument may be used in constant voltage or constant current
applications. The crossover from constant voltage to constant current modes is
smooth and automatic. LEDs indicate the “CV” (constant voltage) or “CC”
(constant current) mode of operation. In constant voltage applications, a current
limit may be preset. When load variations cause the current to reach the preset
limit, the unit then regulates output current rather than output voltage.
Current limits are adjustable from 1.0 mA to maximum, in as little as 0.1 mA
steps. In constant current applications, the maximum voltage may be preset.
When load variations cause current to drop below the regulated value, the unit
reverts to regulated voltage operation at the preset value.
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Reverse polarity protection prevents accidental damage to the power supply
from improper connection to an external device, and current limiting protects
the equipment being powered, as well as the power supply.
The output is isolated from chassis and earth ground, which permits full flexibility
of connections. When needed, the (+) or (-) polarity may be strapped to ground,
or either polarity may be floated to an external voltage. Two supplies may be
connected in series as a 0-to-60 V power source, or two supplies may be
connected in parallel for up to twice the output current.
This power supply is well suited for a wide variety of electrical and electronics
applications in service shops, engineering labs, production testing, school
laboratories, and home use by hobbyists, where precise levels of low current are
required, including 4-20 mA loop testing and calibration or simple IC testing.
Features
• Low 1 mA settable current limit with 0.1 mA resolution
• Output on/off button
• Low ripple and noise
• Excellent regulation
• Constant voltage (CV) and constant current (CC) operation
• Two large, easy-to-read LED displays provide good visibility in bright or low
light
• LED indication for CV and CC modes
• Saved programmed values upon power-up
• RS-232 interface
• Pre-regulator for limiting internal dissipation for higher reliability
• Isolated output
• Overload protection
• Reverse polarity protection
• Power-on self test
• Modern functional configuration conserves bench space and aids
portability
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3 Quick Reference
7 8 6 5 9 1 2
3 4 10
11
12
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3.1 Front Panel
Figure 1 - Front Panel
INDICATORS
Either the CV or CC LED indicators will be lit whenever the unit is operating. The unit
automatically changes from CV to CC operation when the preset current limit is
reached.
1) CV (Constant Voltage) Indicator. The green LED is lit in constant voltage mode.
Unit regulates output voltage at the value set by voltage controls.
2) CC (Constant Current) Indicator. The red LED is lit in constant current mode. Unit
regulates output current at the value set by current controls.
3) Green LED Display. 4-digit display continuously monitors voltage.
4) Red LED Display. 4-digit display continuously monitors current.
VOLTAGE CONTROLS
5) Voltage Coarse Control. Coarse adjustment of output voltage. Read value on the
green LED display.
6) Voltage Fine Control. Fine adjustment of output voltage. Read value on the
green LED display.
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CURRENT CONTROL
15
14
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7) Current Coarse Control. Adjusts current limit in constant voltage mode. Adjusts
constant current value in constant current mode. Current can be read from the
red LED display.
8) Current Fine Control. Adjusts current limit in constant voltage mode. Adjusts
constant current value in constant current mode. Current can be read from the
red LED display.
POWER CONTROLS
9) Power ON-OFF Switch.
OUTPUT TERMINALS & CONTROL
10) “-” Terminal (Black). Negative polarity output terminal.
11) GND Terminal. Earth and chassis ground.
12) “+” Terminal (Red). Positive polarity output terminal.
13) Output On/Off button. Turns output power on or off without powering down the
entire instrument.
3.2 Rear Panel
Figure 2 - Rear Panel
13) Power Cord
14) Fuse
15) RS-232 Interface Connector
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