
Model: 1685B, 1687B, 1688B
Switching DC Power Supplies
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
TestEquipmentDepot.com

Table of Contents
1 USB Interface Connection ............................................................................. 2
1.1 USB (Virtual COM) Configuration ..................................................................................... 2
2 PC Software .................................................................................................. 2
2.1 General Functions and Display ......................................................................................... 2
2.2 External Timed Program ................................................................................................... 5
2.3 Internal Preset Memory ................................................................................................... 6
2.4 Data Log ............................................................................................................................ 7
2.5 Settings ............................................................................................................................. 8
2.6 Power Supply Calibration ................................................................................................. 9
3 Command Set ............................................................................................. 11

1 USB Interface Connection
Users can remotely control the power supply via PC over the USB interface. Upon installation of the USB driver, the
PC can control the instrument over virtual COM.
Connecting Instrument to PC
1. Download the USB drivers from www.bkprecision.com .
2. Connect the included USB cable to the power supply and the USB port on the PC.
3. When Windows recognizes the USB connection, do not follow the default Windows driver installation wizard.
Simply run the setup file from the downloaded USB drivers and follow the prompt to install drivers.
4. The computer will recognize the instrument as a USB (virtual COM) device, meaning it will be detected as a serial
COM port. Windows will automatically assign a COM port to the instrument. Please verify which COM port
Windows has assigned by going into Device Manager.
1.1 USB (Virtual COM) Configuration
The following serial port settings are used by the power supply.
Baudrate: 9600
Data bits: 8
Parity: None
Stop bits: 1
Flow Control: None
2 PC Software
2.1 General Functions and Display
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.
The remote control PC software will display all output voltage, current, and power readings. Voltage and current
values can be set using either the text box or slide bar. The output status is shown on the display panel and can be
clicked to set the power supply output ON or OFF.
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Figure 2.1 - PC Software General Functions and Display
1. Display panel
Shows real-time information of power supply’s output and setting voltage and current.
2. Main configuration and data log display panel
Use to change general setting of program and display data log.
3. Voltage and current setting panel
Use to set output value and output On/Off.
4. File panel
Use to save, load, and print data.
5. File description input
Use to enter description of program or log file.
6. Program running cycle setting panel
Use to set running cycle for External Timed Program.
7. Information panel
Use to display maximum voltage/current, sampling time, upper voltage/current limit, and software
version.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
TestEquipmentDepot.com
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Figure 2.2 - Display Panel
Figure 2.3 - Output Configuration Panel
You can directly type the desired output voltage and output current and then click “Set” button to set the value or
use the slide bar to adjust the value.
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