Pump failure and shutdown signals
Thread Content
Can the failure and stop signals of the pump be sent to the DCS at the same time?
Sure, a fault and a stop are two different signals
I’ve never seen this phenomenon before; two signals can appear at the same time
Can’t just use two DI points? If they are displayed on the DCS at the same time, then there’s a problem
It is not a problem from the perspective of the DCS system itself for these two signals to be sent to it at the same time. However, it is unclear whether these two signals can appear simultaneously from an electrical standpoint. For example, if a fault signal is generated and the pump was originally running, a shutdown signal will inevitably be sent immediately. If both signals are sent to the DCS system, then two alarm signals will appear. But in many facilities, only the shutdown signal is sent to the DCS, while the fault signal is not; therefore, it is possible that two alarms do not appear at the same time.
The motor fault signal is derived from the thermal relay in the electrical system, while the stop signal comes from the auxiliary contacts of the contactors in the electrical system. This signal is used as the operation signal; its inverse is then used as the stop signal