On page 294 of HG/T20512-2014, it is stated that signals of different levels should not share the same multi-core cable or the same junction box...
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This post was last edited by hesonchang214 on 2020-4-27 07:32. I have a junction box on site where the DO points are located; now I want to place the AI points in this same junction box. Is it okay to use the same main cable to enter the cabinet room? Is there a conflict with this specification?
The same cable can only be used for the same type of signal, such as 4-20mA signals, 24VDC switch signals, thermal resistors, thermocouples, etc. The signals within one junction box should also be of the same type.
Mainly, the voltage level of the same main cable must be the same!
One signal is analog while the other is digital; they cannot be transmitted over the same cable.
You have already uploaded the specifications; what more is there to ask?
Thank you all for your replies. I mainly didn’t understand the concept of \"different levels\" in the original specifications; I have found an explanation of level classification in the SH/T3019-2016 Standard for the Design of Instrumentation and Pipeline Systems in the Petrochemical Industry.
Is it possible or not? \ud83d\ude0a
According to 7.1.124V dc DIDO in the SH7091 specifications, both 4~20MA represent medium-level voltage ranges; therefore, can they not be shared on the same wiring and in the same enclosure?