Which specification states that interlocking signals must use hardwired connections?
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I would like to know in which specification it is stated that interlock signals must be transmitted via hard wires. We require that the interlock signals be connected to the DCS using hard wires, but the design team refuses to comply; several of the interlock condition signals are sent to the DCS using Modbus communication. I checked document 20511, and there isn’t any clause stating that interlock signals must necessarily be transmitted via hard wires. Please advise!
SH 3018-2003 Explanation of Provisions 9.6 Safety instrument systems should use 4-20mA DC analog signals; field buses, HART, or other wired communication signals should not be employed
GBT 50770-2013 6.1.5 Measurement instruments shall not use field buses or other communication methods as the input signals for the seat safety instrument system.
Shouldn’t instrument signals be transmitted via flexible wires? Why must hard wires be used? You are the client side, so how can the design institute even challenge you? They’re really tough; take care of them
There are clear regulations in 50770
Fortunately, I’ve never encountered a landlord like you. Whether it’s A, B, C, or D, it’s all for work purposes; there’s no deep hatred between anyone, and everyone should respect one another.
There is no such mandatory requirement for DCS systems; it applies only to SIS/ESD, as specified in clause 9.1.5 of GBT 50770-2013.
This is basic common sense – a design firm has to work according to the client’s requirements. You can’t just do whatever you want; if your designs force me to spend all my time fixing things, what’s the point? I pay you to have your firm carry out the design work, yet you don’t follow instructions. Then what’s the use of you?
9.1.5 states that the connection between the safety system and other systems should be a hard connection; it’s not necessary to use physical wires, right?
This post was last edited by lotos1987 on 2019-1-19 at 22:10. By \"hard wire\", it is not meant a rigid cable; rather, it refers to the fact that the signals in such a cable are not in software-encoded formats like Modbus or Profibus, but rather come from hardware circuit signals such as 4-20mA or 0-10V. Furthermore, the design institute must carry out its design in accordance with relevant standards, and while respecting the mandatory provisions of these standards, it should strive to meet the client’s requirements as much as possible by taking into account technological advancements. However, violations of the regulations cannot be tolerated; otherwise, corresponding legal responsibilities must be assumed. If the client is too demanding, then why hire a design firm at all?