Panel items organization tips

[Penko Mitev]

Hey guys! Today the customer of our most recent machine went to our plant to monitor the machine and to accept it. It was the third machine I am programming and I did the panel almost myself because my father was very busy constructing the mechanics of other machines. So, I figured out a lot of things while chasing windmills in the panel. There is one thing that makes me not very happy with the result - wiring. My problem is that I wired for example outputs and after that some 24 V and - 24 V wires and some other and everything became a real mess when it comes to cables. My question is - what do you do to isolate different cables one from another as much as possible? I mean, I read somewhere that it is good practice to isolate voltage cables for digital signal ones and also phase and negative wires. Is it important to first wire voltage cables and after that inputs and outputs or there are other hints which are applicable when considering panels? Let's say I most commonly have a MAIN SWITCH, START/STOP, EMERGENCY STOP, contactors(for handling the previous three's logic), PLC. Sometimes there are also frequency-controller motors so their amplifiers also get installed in the panel. Looking forward to hearing from you :). Penko

[gleblanc]

I know this is old, just got back to reading this forum after quite some time off In general, it's probably not terribly important to separate digital control signal wires (generally digital I/O and relay I/O from power wires. These likely won't be changing very quickly, and are unlike to have much effect on other wires that are running parallel to them. Analog signal wires of any sort should be kept together, and away from any other wires whenever possible. In the past I've put my analog I/O cards at the end of the PLC cabinet away from the power supply, and run cables out opposite the direction of the power supply. Digital I/O goes out the same direction as the power supply wiring. If I have a number of wires that start and end at the same locations, I will often zip-tie them together. HTH, Greg

[Andrew]

Most industrial panel are set up very alike, Transformer at the top left corner, PLC and Power supplies in the center, and Input/Output terminal blocks and intrinsic barriers at the bottom. It's very good practice to not run signal wires in Parallel with voltage carrying wires because of possible induced voltage, crisscrossing is fine though and of-course shielded signal wires and lower voltage lines don't apply to this. Doing this though is unfortunately not always possible. Key to a nice panel is proper color coding and proper use of wiring duct. Edited November 18, 2010 by Andrew

[Phoenix Contact USA]

Greg's comments were spot on. It is good to keep analog signals segregated from other devices because of noise. To add to his point, if you are looking for a simple and clean way to organize our system, it would be good to use system cabling with a ribbon cable to clean up your cabinet.