Is the analog output a 1771-OFE, or another device that takes a bit pattern and converts to analog going out to the valve? Writing to an output word implies the latter, possibly something on remote I/O or discrete-to-analog.
I'm guessing it's not an 1771-OFE module, given that the max scaled range for BCD or Binary is ±9999
Looking at the values being moved in - 20,000, 16,000, 24,000.
@MarkNightingale, what is your analogue module?