Some of the company’s units are equipped with DCS systems and SIS systems
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For the same process parameters, such as temperature, what should be the setting for the alarm parameters on the DCS system and the SIS system? Should they be set to the same values or different ones?
It depends on the process design requirements and actual needs. However, the process is led by the technology team.
The DCS alarm process is decisive. SIS depends on the values provided by the design institute. Don’t make random changes; you will be held responsible if something goes wrong.
The set value of SIS is generally between the HH alarm value in the DCS and the on-site safety valve value
The alarm values on the DCS should trigger earlier than those on the SIS, in order to prevent accidents through interlocks ahead of time
Surely DCS is implemented earlier than SIS; SIS is the final stage.
Are there any specific setting standards or principles?
The design institute has determined that (the high-high setpoint of DCS is lower than that of SIS)
The SIS has issued an alarm; basically, the interlock value has been triggered. The interlock value of the DCS must fall within the alarm value range set by the SIS; it can be equal to that value, for example, the DCS high-alarm value ≤ the SIS interlock value.
Normal DCS parameters are lower than those of SIS interlock parameters; DCS is used for operation and control, while SIS serves as the ultimate safety safeguard