AO is used for interlocking
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There is a control damper that requires SIS interlock; no solenoid valve has been installed. The design team designed it to be controlled by AO within the SIS, with AO used for interlocking as well. What regulatory basis exists that would allow the design institute to change to using AO for control in the DCS and DO interlocks in the SIS?
I’ve never seen AO used in SIS.
Where are the analog signals in SIS? Aren’t they all digital switch signals? Either on or off
Just ask them for it – why do we need standards?
So, if the temperature is high or low, and the pressure is also high or low, how should the values be determined? Aren’t these all analog inputs? Analog output is rarely used in general, but that doesn’t mean there are no analog outputs.
Levels, pressure, temperature, etc., are all A signals, but what is sent to SIS is a D signal
What industry do you belong to? Some standards are applicable to the industry.
Indeed, there are special cases where SIS-AOR is used for interlocking, and in such situations it is necessary to clarify all the interlocking requirements. The AO cards of SIS are not very cheap, so it’s necessary to weigh them carefully from a cost-performance perspective.