RTU's Remote Terminal Units

😀hi there, me again, does any one have any ideas about remote terminal units? its used to monitor field devices such as pumps, switchgears, motors, etc, i need help in analyzing & fixing a texas instrument rtu here in my worksite, the prob is this, for example i hv 4 pumps connected to my rtu, when i simulate pump # 1 in the termination panel pump # 4 also reports to the monitoring computer, this should not be becoz i only simulated pump 1 only, so pump 1 should be the only one to report on the monitoring computer, ive asked our software engnr to check the databse on the server & he said its all ok, i did tried to replace the input card where all the LED indicators are located but the prob is still der, so the nxt step is to replace the main rtu board, then it worked fine, no more unwanted points reported to the monitoring cmputer, ive noticed that there are 8 optoisolators in the input of the rtu, i traced the outputs of the optoisolators and it goes to other chips, any ideas pls help tnx