SIS and DCS control the same pump
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Both the SIS and DCS need to interlock to stop the pump – how should the wiring be done?
Check the electrical diagram; it is connected to the electrical shutdown output point
The DCS interlock stop signal can be connected to the SIS system’s interlock stop logic in order to jointly stop the pump
Whatever signal the electrical system requires, that’s the signal that will be provided for control.
The pump-stop signals from the DCS and SIS can be connected in series at the pump-stop circuit in the secondary circuit on the electrical side.
Based on the requirements of the SIS, if a SIL2 level or higher is required, an independent main relay is needed to control the pump; if it’s SIL1 or lower, simply connecting a contact in series with the secondary circuit will suffice. However, the SIS must send a signal to the DCS to indicate that it has been activated, so that the DCS can stop its outputs.
The pump shutdown signals from both the DCS and SIS are sent to the electrical pump control circuit, where they are connected in series with the on-site pump shutdown switch signals