instrument cable laying and segregation in cable trays

Hello All,
my question is that would it be possible to put instrument multicore DO cables in a tray with instrument multicore DI,AO and AI cables in a distance about 330 meters? any problem would be possible to happen such as due to Do signal ON and OFF excitation ( 24VDC on-off signal of valves) AO or AI or particularly DI signals to be interfered? should I segregate them? is there any standard in this regard? any reply would be appreciated.
 
sabak149,

Depending on who you ask, EVERY conductor (core) is a signal cable, so it should be acceptable to run just about every cable together in any wireway--cable tray, conduit, cable vault, cable raceway, cable pit, etc.

It's really the switching of signals (low-voltage--that is, less than approximately 24-50 VAC) that causes many of the problems with other true low-voltage wiring when run side-by-side for any appreciable distance (and 330 meters is an appreciable distance in my estimation and experience. Between the switching (ON, OFF) and the amount of current and the inductive effects of energizing and de-energizing some coils/devices, the effects on surrouding wire and signals can be pretty significant.

You really need to understand what the controller manufacturer (the PLC manufacturer, or the DCS manufacturer, or whatever the wiring is that's being connected to the controller(s) to understand what THEIR requirements are for signal level segregation.

Are there "standards"? Well, there's a saying I like to use to answer that: "The good thing about standards is that there are SO MANY of them!" Really, the "standard" you need to be using and referring to is whatever is the practice in the plant where the equipment is going to be located. And that can be very subjective, because in some plants where there are multiple processes and controllers, and technicians and supervisors, there can be multiple "standards."

I wish there was a more definitive answer to your question--or, rather, that I had a more definitive answer to your question. It's really a very nebulous and polarizing question depending on the experiences of the people you ask it of. If the loads of the DOs (all being driven at 24 VDC) are relatively low (less than an ampere or so), and they aren't being switched on and off quickly it's probably okay, But, again, the control equipment manufacturers--AND the plant personnel where the equipment will be installed!--will be the best to ask, and answer, this question.

Best of luck with your endeavour!
 
The 24VDC DO and DI cables are the same type and class so they can go together.
The 24VDC AI and AO are the same voltage class as well and since they are shielded twisted pair they will be fine in the same cable tray with the 24VDC discrete cables.
What you do NOT want to mix with 24VDC analogue cables are higher voltage and power AC wiring, it will induce noise and current into your low voltage cabling.

IF any of the cables are Intrinsically Safe, they need to be separated from the non-IS cables with metal dividers.

good luck
 
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