Is it correct to draw the interlock logic diagram this way?
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I would like to ask the teachers whether this approach for creating the DCS interlock logic diagram is correct. My reasoning is that an ON state of the soft button at the logic input end represents 1, which signifies activation, while an OFF state represents 0, indicating normal operation. So when creating the interlock logic diagram for SIS, the logic needs to be inverted; is that the case for the logic input terminals?
I’m not quite sure what you mean by ‘illogical’
This post was last edited by jlshnlhj on 2022-4-9 at 15:55. You don’t understand why it’s best for interlock logic diagrams to use inverse logic; the key point with inverse logic is that hard connections are triggered by a \"0\". What’s important here are the hard connections themselves – for example, an increase in the contact resistance of contacts, or breaks in wires caused by mice or construction work. Such potential faults are not easy to detect in a timely manner, which can result in the interlock \"1\" signal not being detected at critical moments (including I/O signals). A faulty interlock is better than no interlock at all. Therefore, the HS2001 (DCS hard button) is connected via wires, and it is best to trigger it at “0”.
Teacher, for the hardwired HS2001 (OFF) setting, it triggers in the SIS at state 0, while in the DCS it triggers at state 1. Is that correct?
This is exactly the opposite of what he said; for a hard-wired emergency stop button, it’s best for the interlock to be triggered by the disconnection of the contacts.
This post was last edited by jlshnlhj on 2022-4-9 at 16:35. The understanding is correct, thorough, and accurate. "The counterlogic is that the emphasis is on the use of “0” to trigger a hard connection; it’s the hard connection that’s important, not SIS and DCS. SIS interlock is interlock, and DCS interlock is also interlock.
This post was last edited by jlshnlhj on 2022-4-9 at 16:34. The key point of \"anti-logic\" is that a hard connection is triggered by a \"0\"; it emphasizes that it is a hard connection, not an SIS or DCS connection. SIS interlock is interlock, and DCS interlock is also interlock. When DCS first appeared, there was no SIS yet; at that time, interlocks were all handled by DCS. Even in the era of electric or even pneumatic instruments, without DCS or SIS, interlocks already existed; they were simple logical interlocks made up of relays, utilizing the normally open/normally closed states of these relays, with activation based on the value \"0\". The idea of using “0” as a trigger was proposed by our unit at that time. But at that time it was only implemented within the organization.
So if it’s drawn on a diagram, is hard wiring OFF the normal state, and ON when triggered?
Is the case for soft buttons that the condition is met, i.e., ON?