[I wasn't sure what location to categorize this post under; please let me know if there is a better place for it]
I am using the PyVISA library (with pyvisa-py, psutil, and zeroconf packages also installed) to write a script to communicate with a Compax3 device via RS232. It seems to work fine except for when I write to bit 7 (i.e. I7) and beyond in control word 1000.3 with a nonzero value (ex: given all inputs start as 0, writing bit value '1' to I7 by sending 'o1000.3=10000000'). In that case, reading from the device after writing gives the error message !FF11, which means "value is not valid" according to the .txt file listing all error messages on the Compax3 site, and subsequent reads confirm that the bit is left as '0' and was not written to.
Why would this error be occurring?
I have attached the relevant portion of the script here. Here, obj_num is the number of the control word (ex: 1000.3 for inputs), item is the label for the value being changed (ex: I7), and wr_value is what the value is being changed to (ex: 1). All inputs are assumed to be strings.
