Safeguard 400 system make channel test for field device.
My system is Safeguard 400, version 1.6/4.
Currently, due to obsolete status of filed device (solenoid valve), we have to change to new one which is same manufacturer but different model and mostly similar resistance.
But when we replace new solenoid into loop at field (Normally Energized/DSTD N020V01), the system reports "No pulse response" in Safety Message and sometimes intermittently de-energize the loop.
(Cabinet --> Filed junction box --> field device)
However, when we took the solenoid to connect to Marshalling cabinet in Control room, (means eliminating wires from control room cabinet to field), there is not any message. (Cabinet --> device).
We've known that there are the combined condition of capacity, impedance on entire loop for Safeguard system to do their channel test. But the device change due to obsolete is MUST be.
Can anyone give me advice or solution for field device and loop?
Thanks in advance.
No pulse response typically comes due to internal SG issues like blocked DO, MAN, INV set to =1 or simply the test has for some reasons been skipped.<No pulse response come because the AND gate (Yellow) is never set and basically has nothing to do with field device itself.
Here is what the safety manual says