Abnormal feedback from the switch
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(1) There is a shut-off valve on site, and there are always problems when adjusting the switch feedback (mechanical contacts) – either the feedback is incorrect or both types of feedback appear. In the end, the technician on site said that when installing the feedback devices, one should install the lower one (the shutdown feedback) first, and then the other one. Is there such a practice? (2) Where is the contactless (NUMAR signal) response used? Is it installed in a site with an explosion protection class of Zone 0?
(1) I’ve encountered this problem before; your instructor is right – it’s necessary to debug them one by one. For example, when turning something on, adjust the contact point related to the activation feedback. When turning it off, debug the contact point for the shutdown feedback
Debugging definitely involves doing it step by step. What I want to ask is: the reply device was installed on site, but during debugging it was found that sometimes both replies were present, while at other times only one reply was there, with the other one completely missing. It turned out to be a installation issue – the lower reply device should be installed first; after debugging that one, then the other reply device can be installed and debugged as well. Is that correct?
Yes. Ensure one feedback system is working properly before going on to adjust another one