We have several remote sites (controllogix v28) and data usage is a huge problem. We’ve managed to set our scan classes appropriately so that our overall bandwidth usage is generally pretty low, but something that’s very confusing is that according to wireshark and our bandwidth report from the modem, our upload amount and download amount to the plc is always generally the same. Even when we were pulling down all of the information from the plc every few seconds, the up and down usage would be the same. example: 512 MB download , 511 MB upload for one day.
Shouldnt the usage be primarily upload from the PLC? Nothing else except Ignition is talking to it over the modem.