Interlock for organic pump fault signals in SIS
Thread Content
In the SIS, there is interlocking for pump failure signals; considering fault safety, should a normally closed signal from the electrical system be used, so that the normal operating contact of the pump remains closed while its failure contact opens?
The pump failure signal should be connected to normally closed contacts (NC) first, to ensure that the SIS automatically enters a safe state in the event of a wire break or equipment failure. If the device only supports normally open contacts (NO), logical inversion and redundant design are required, while HAZOP/LOPA analysis is used to verify whether the risks are acceptable
The unit PLC signals have been sent over.
There is no need for pump fault signals to be sent to the SIS. Pumps generally have backup units; if the pump is a critical piece of equipment, then the stop signal can be sent to the SIS 2oo2