Is there a connection between the unit’s SIS and CCC systems?

In terms of our unit, SIS is used only for emergency shutdowns, while CCC is used for anti-surge control. Generally, there is no requirement to install SIS in the unit itself; however, the entire process related to the unit may have SIS systems, which includes the unit as well

1. The SIS of the unit is used to protect it, and it mainly includes equipment interlocks and process interlocks. For example, process interlocks: high liquid level in the tanks between sections, high temperatures of inlet and outlet gases, etc ； Equipment interlocks: such as shafting protection, dry gas sealing, lubricating oil and control oil pressures, etc. 2. CCC, the unit control system, is mainly used for speed regulation and performance control, as well as anti-surge control. As part of the control systems for compressors and turbines, the two are inevitably connected: A. The CCC system has a host computer for operation purposes, and the information from the SIS needs to be transmitted to the CCC system for display ； B. The interlock of SIS is included as part of the allowable start conditions for the CCC screen ； C, CCC, and SIS simultaneously control the solenoid valve of the anti-surge valve. For example, when the CCC detection shows that the compressor has reached the surge limit, it is necessary to fully open the anti-surge valve; similarly, when the SIS interlock is triggered, the anti-surge valve also needs to be fully opened. There must be some form of signal exchange between the two systems. The attachment is a structural diagram of the control system for a project: CCC is used for unit control, HIMA is used for unit interlocks, along with the Bentley system, the DCS and SIS of the equipment. It shows on-site displays, local instruments, and MCCs, providing a brief overview of the relationships between these components for reference.

Thank you so much to the experts for their answers; I’ve learned a lot