© 2020 Virginia Diodes, Inc.
—All Rights Reserved
7 October 2020
Set Commands: Continued
C1
– will set the calibration heater to the preset value of 100 µW if the back panel Internal Calibration Switch is not set to “OFF.”
Bytes 4-7 must be sent but the receiver ignores.
C2
– will set the calibration heater to the preset value of 1 mW if the back panel Internal Calibration Switch is not set to “OFF.”
Bytes 4-7 must be sent but the receiver ignores.
C3
– will set the calibration heater to the preset value of 10 mW if the back panel Internal Calibration Switch is not set to “OFF.”
Bytes 4-7 must be sent but the receiver ignores.
C4
– will set the calibration heater to the preset value of 100 mW if the back panel Internal Calibration Switch is not set to “OFF.”
Bytes 4-7 must be sent but the receiver ignores.
Query commands
D1
– will request one power output sample. Bytes 4-7 must be sent but the receiver ignores. No response will be sent until new
data is available, up to 1 sec on the 200
W range.
DS
– will request streaming of power output samples, (data sent at the internal sample rate). Bytes 4 through 7 must be sent but
the receiver ignores. Streaming will continue until the PM5B
gets a ‘D1’ command or until the power is turned off. The internal
sample rate is 1 Hz on 200
W range, 5 Hz on 2 mW range, 20 Hz on 20 mW range and 35 Hz on 200 mW range.
VC
– will request the firmware code and secondary firmware code revision data. Bytes 4 through 7 must be sent but the receiver
ignores.
High Resolution Get Power Command
The PM4 command structure returns 16 bits representing measured power, which sometimes is not enough for the PM5B. An
alternate command is available for the PM5B that has greater resolution.
Sending the following series of bytes will prompt the PM5B to return the measurement result over the USB with higher resolution:
38, 1, 2, 37
After receiving these bytes the PM5B will measure and return 14 bytes. The first returned byte is an error byte. If there was a
communication error this byte will be 0xAB, otherwise it will be 0x55. The remaining 13 bytes will be an ASCII text string in
exponential notation representing power in milliwatts.
The PM5B determines if there was a communication error by calculating the
“Exclusive OR” result of the first three bytes in the
command string and compares to the last byte sent. The last byte (37) in the command string is the
“Exclusive OR” combination of
the previous three bytes and must match the
“Exclusive OR” result calculated by the PM5B.
Set, Query and Get Power Commands
