How Do you Wire Your OPTO?

We are really happy with our Opto PAC systems, and comission new ones for plant efficiency improvement (cost reduction, error proofing) projects probably 5-6 times per year. Every implementation is a little smoother than the last one, except for the wiring.

My background is in Mechanical/Manufacturing Engineering, and i am the project manager and lead engineer on most projects. Typically, wiring diagrams are made in solidworks (as a drawing) and excel ( as a pinout ) as these are the packages I have access to and am familiar with. This is very clunky, as everything is done manually without intelligent connections/pinout generation from a schematic. As such, small errors can balloon very easily.

Further, in actually running the wiring from the Opto cards to the test fixtures/equipment there is a substantial amount of labor, and there is the matter of making everything as easy to repair/maintain as possible.

I am very interested in what other Opto users use in these areas.

1.) Does anyone have a schematic program they use (possibly with a custom Opto library?) to generate pinouts/boms?

2.) What Cabling/Interconnect products do you typically use with your Opto, especially in going from control cabinet to equipment?



Hi Travis,

Excellent question! I’m looking forward to seeing what other folks have to share on this. Just in case you haven’t heard of our TEX line of accessories, here’s an OptoMinute video to give you and overview of how they can make wiring from the modules easier.

There are a couple of ways our tools can help you with a BOM. In modern versions of PAC Control, go to File > View/Print > Bill of Materials:

Also, if you haven’t tried the Snap I/O Unit Configurator on our website (under the orange “Learn” tab then “Animated Demos”), it’s fun to use and can also help you build a BOM:

Please share any comments/requests/suggestions!


Hi Travis
I have not settled on a specific format for conveying schematically the configuration of our Opto gear for as built manuals. i have used TurboCAD for schematics and have found it ok once you get the hang of snaps, but not very attractive. i have used Visio (Opto 22 supply nice visio libraries) to graphically show the racks and terminations but sometimes it plays dirty with the way it routes connections. however it is quite attractive and really helps to paint a clear picture of how things will look. But with both, none can generate a BOM or pinout (maybe they could if you wrote some macro’s)

I do like what Mary suggested regarding BOM and I/O point mappings and the export option of comma separated is a great idea. Good for importing into spreadsheets.

As far as wiring, our installations are really well defined at the demarcation point of field/control. we generally use a 0.5mm2 single core building wire from I/O module to terminal strip. It is a bit laborious but i always try to use snap straps where i can and with internally connected references (AIV, AOV modules) i only run 1 cable. We have recently migrated from screw-clamp terminals to spring to try and minimize the wiring time and it has definitely helped. we do not use any dressings on the cables as this can sometimes be more problem than what its worth. we label our cables with a cable sleeve with a printed label insert. this to me appears to take the most amount of time. we always try to be informative with our labels as cable schedules go missing, so things like pump/fan on will be labeled FANx S/S or PUMPx S/S etc… we do not used the TEX cables because you cannot label the I/O end.

I hope this helps


I also use a very clunky system of Excel and uStation. For panels I love the TEX cables. Labeling for the TEX wire at the terminal block always refers to the module it originates from. The back panel in the picture below uses 600V terminals and they take a lot of real estate. But we use smaller terminals as well and they are always ring terminal to help prevent connection issues due to vibration.

Nice panel work Chris.

If you want the ultimate schmatic and plant electrical or product electrical schematic drawing package that does everything and more, and if you’re ready to spend $6k, then get EPLAN. This is what the Europeans use almost exclusivly and having taken a seminar, I can tell you it is the best. There is essentially NO drawing. You simply pick, point and click. Unlike Autocad and many others, it is a database packge with a gui front end for the creation of the schematic. Everything is based on the database. If you need a 3 phase drawing, you pick the appropriate symbols and click on the page and it draws all the wires automatically even if you’re moving stuff around, removing stuff, or putting in new stuff, it doesn’t matter.
In so far as your panel goes, I use mil spec wire instead of THHN or THW. It is much smaller diameter so you can use 18 gauge generally or 16 guage where needed and you will have so much space left in the wire duct, it’s a no brainer.
I agree with Chris, the cables for around $34 each are the only way to go, although my only comment is that they could have been designed using a much smaller sheath. This will eliminate at least 8 terminations per module. The breakout boards are really nice especially the output 16 point relay boards. Use 2 of these with a 32 point output module and you have 32 points of 10 amps each. Since the 32 point modules use cables, connecting them to the breakout boards is easy.
One last point. Trying to build a control panel or almost any wiring system no matter how simple you think it is, is always three times more confusing than you think. Thererfore, the number one rule is, don’t start wiring anything until you have a thoroughly vetted schematic, right down to the last terminal block or terminal number, end of story.