I work on 2 specific machines that use RS-232 comm's in a loop to multiple items. Definitely not RS-485 as I test them when needed.
One is an electroplating system that has 8 rectifier power supplies and 4 pulse modulator controls wired in a single serial loop. Each item has a specific RS-232 address the HMI/SCADA sends commands to set with a bank of DIP switches.
The other is actually a group of high resolution printers that have 10 servo controlled motors and 4 IR cameras all controlled through a single RS-232 cable. Each servo control and camera has a unique address from 16384 to 32767 programmed from the factory that has to be changed in the program if replaced.
One is an electroplating system that has 8 rectifier power supplies and 4 pulse modulator controls wired in a single serial loop. Each item has a specific RS-232 address the HMI/SCADA sends commands to set with a bank of DIP switches.
The other is actually a group of high resolution printers that have 10 servo controlled motors and 4 IR cameras all controlled through a single RS-232 cable. Each servo control and camera has a unique address from 16384 to 32767 programmed from the factory that has to be changed in the program if replaced.