xln_power_supply

BK Precision XLN High Power Programmable DC Power Supplies

These python scripts are for the BK XLN Series High Power Programmable DC Power Supplies

Models

Models: XLN3640, XLN6024, XLN8018, XLN10014, XLN15010, XLN30052, XLN60026

Documentation

XLN Power Supply Manual: Series Manual
XLN Power Supply Data Sheet: Series Data Sheet
Serial-to-USB Bridge: CP1202
BK 8600 Electronic Load Programming Manual: Programming Manual

Serial Port Configuration

The XLN power supplies have the following configuration:

bk.baudrate=57600
bk.bytesize=8
bk.parity='N'
bk.stopbits=1
bk.xonxoff=False
bk.rtscts=False
bk.dsrdtr=False

The above settings are the default settings for the pyserial module, except the baudrate, which is 9600baud. You have to use 57600baud with the XLN power supplies.

Scripts Usage

The following steps must be done before using these scripts:

1. Identify the serial port name of your instrument. On Windows, this is a COMxx port name. On MacOS, this is /dev/tty.usbserial-{sernum}, where {sernum} is the serial number of the XLN power supply. You can use the script list_ports.py to list all serial port devices in your system, and identify the correct Silicon Labs CP1202 USB Bridge device port to use.
2. Set the portname variable to your instrument serial port name.
3. Change the model_id variable to your XLN power supply model.

import serial
import time

script_ver = "v1.0.0"
model_id = b'XLN3640'                       # change the model_id to your XLN model
portname = '/dev/tty.usbserial-275K22178'   # change the device port name for your device name!
                                            # on windows use 'COMxx'

4. The XLN power supplies use an internal serial-to-USB bridge chip (CP1202), that is bus-powered by the USB cable. This means that even when the power supply is unpowered, or when the internal processor is unresponsive, the serial port will be normally enumerated and opened. This requires another level of authentication before starting sending commands to the XLN power supply. We verify that the MODEL string returned by the instrument matches the expected model_id string, and issue and error when it fails to return the correct model string.

Scripts included in this folder

• xln_id.py — retrieves ID info of the connected XLN power supply
• xln_clr_pgm.py — clears all internal stored programs
• xln_gen_pgm.py — generates a staircase waveform in PROG1
• xln_gen_pgm_sine.py — generates a sinewave burst waveform in PROG1
• xln_run_pgm.py — executes the program stored at PROG1
• xln_wave.py — generate a staircase waveform and display realtime voltage and current
• list_ports.py – lists all USB serial ports (USB CDC) in the system. Use to find your serial port. The XLN series has a Silicon Labs CP1202 Serial to USB bridge.

SCPI commands for XLN Power Supplies

The SCPI commands that you can send via serial port to the XLN Power Supply are detailed in the XLN Series Manual, at pages 1-60 to 1-74. These commands are used as exemplified in the scripts. The following python code snippet sets the power supply output to 12Vdc:

import serial
...
bk = serial.Serial()                    # obtain 'bk' serial port object
... # configure port, verify XLN is responding
bk.write("SOUR:VOLT 12.0\r\n".encode()) # set output voltage to 12Vdc
bk.write("OUTP ON\r\n".encode())        # turn output voltage ON
... 
bk.close()                              # close serial port

Operating Tips for the XLN Series

Whenever a remote command is received from the serial port, the XLN power supply enters REMOTE MODE, and the front display indicates RMT in the lower-right corner.

The frontal keyboard is LOCKED in RMT mode, and the user cannot access any local function.

To restore local control, you need to press the decimal point key [.] which unlocks the keypad.

---