Issues related to flammable and toxic gas detectors
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Dear teachers, if combustible and toxic detectors are to have DCS involved in interlocking, how should it be done? Must one first connect to the GDS before connecting to the DCS? There is an interlock mechanism that shuts off the valves when the concentration of combustible gases reaches a certain level; so which system is responsible for carrying out this action?
What are valves used for? If the valve is a process valve, generally the gas detection signal is sent to the GDS, which then sends a dry contact signal to the DCS; the DCS is responsible for interlocking the valve ； If the valve is independent of the process system, such as a valve used for spraying, it can be directly connected to the GDS, with the GDS then being used to interlock the valve (provided that the GDS has the necessary connections)
A 1:2 gate can be used, or GDS can be input first with the DO output going to DCS for setting conditions; the DO output from DCS is then used to activate the valves.
It is a process valve; when the detector gives an alarm, it is necessary to close the valve of the process pipeline
Thank you, so both of these two options are acceptable?
Well, as long as it doesn’t involve SIS interlocking, it’s easy to handle.
Note that GDS and DCS should be independent of each other