Over the past three or four years PLc's communication systems have become available which allow them to act in the same way as a DCS (Distributed control system). Now there is really no great difference between a DCS and a group of PLC's with a SCADA for display. You will find that the big DCS...
I agree with DJS but if you do not have this facility then I assume you are looking for sudden pressure changes as the pumps stop working. The normal time changes will be slow (again an assumption) so if you store the pressure and then set a timer, when the timer runs out after say 1 minute...
