Control Panel Build Series Part 18- Wiring Digital Signals

Wiring_Digital_Signals_Control_Panel_Build_Series_Part_18.pdf

Wiring: Digital Signals

Can be different depending on the hardware that is being used - Some PLC’s have prewired harnesses that are provided - In which case you will only have to wire the terminal block side of the signal - Sometimes you must wire both the PLC and the terminal block side Wire size can vary depending on signal types.   Read PLC hardware manual to get a clear understanding of how the circuits should be wired   It is a good idea to have some kind of disconnect or fused protection on each signal so that you can isolate that signal if necessary

  Make sure to take time as each termination is made to not fray or “birdcage the wire in anyway If Jumpers are being used to distribute power, make sure that each terminal the jumper is being inserted into is secured if necessary Reference the drawings often through the process to ensure that nothing is missed, and each signal is being wired correctly.

Transcript:

[0m:4s] Hi I'm Josh Bloom, welcome to another video in the RSP Supply education series. If you find that these videos are helpful to you, it certainly helps us out if you could give us a big thumbs up and subscribe to our channel.
[0m:16s] In today's video, we will move on to the next step in building an industrial control panel. If you haven't already seen the other videos in this series, we encourage you to go back and watch from the beginning so that you might better understand the entire process.
[0m:30s] The step in which we will focus on today is continuing on in the wiring phase of the build, but focusing on wiring the digital inputs and outputs for our control panel.
[0m:42s] And now that we have wired all of the power distribution throughout the panel, we can begin to wire some of the IO, which is where all of the external devices and instruments will be wired into. When wiring IO and a panel, it is easy to make a mistake due to the fact that there can be so many termination points. So it is important to follow your schematics and take your time.
[1m:7s] As always, the process in which we discuss today is just one method of many that can be performed to achieve the very same results. So let's get to it.
[1m:16s] When wiring digital signals it's important to understand that

[1m:21s] depending on the hardware that is actually being used,
[1m:25s] you may wire it differently. So, in some cases, a PLC will come with a prewired wire harness that you will use on the PLC side of your digital signals. In the case of the panel that we're building, this is actually what is the case. This particular PLC has a harness that we plug into the PLC,

[1m:49s] and we only wire the terminal block side of this particular signal in our cabinet. Now, some other PLCs don't offer this and so you have to wire both the PLC side as well as the terminal block side. So, for the case of this particular unit we're going to be wiring these digital signals just on the terminal block side. In another video we'll show you how to wire the PLC, this particular PLC in any case, just said that you can get an idea how you might wire this type of PLC. But keep in mind depending on the hardware that you have will greatly dictate how you wire your signals. The next thing you want to consider on wiring digital signals is the wire size. We talked about this a lot throughout this panel build. Now when you're doing signals we're not typically seeing as much current

[2m:40s] pass through these signals, so we can use smaller wire. Normally when there is no prewired harness provided, we try to use a 16 or 18 gauge wire, which is probably more than necessary, but we like to try to use as large of wire as possible, just to be safe. In the case of these prewired harnesses that we're using for this particular build, they're going to be either a 22 or 24 gauge wire are pretty small. But again, the amount of current that is passing through these signal wires is really, really minimal. These are factory wire harnesses, so there's really no concern for too much current passing through and burning up the insulation and causing any kind of hazard. So again, make sure that you're speaking wires are size between somewhere between 16 and 24 gauge wire.

[3m:26s] It's also important to make sure that we're reading
[3m:29s] the PLC manual, the hardware manual, so that we can very clearly understand how to wire these digital circuits. Each PLC functions a little bit differently. So, they're not all wired the same. So we want to make sure that we understand how the circuit should be wired so that we can make sure that we have we're wiring proper loops. We need to make sure that we're putting we're putting our power where it needs to go and we're putting neutral or DC negative

[4m:3s] where it needs to go, so that we ensure that we have a proper loop, so that our signals can function and get back to our PLC as expected.
[4m:12s] It's also a good idea to have some kind of a disconnect or fuse protection on each individual signal so that we can isolate each signal if necessary. Now, this is a good idea so that if in the field we need to replace or service an instrumented device in the field, we can isolate the power going out to that instrument, and again, that's probably going to be very little power, but we still want to be able to isolate that, so being able to remove fuse or lift up a disconnect, we can isolate that device or instrument so that we can service it or replace it. So being able to have that kind of protection is a good idea.

[4m:49s] It also protects the PLC from possible surges or over current events so that the PLC doesn't see that

[4m:57s] that spike and it protects that hardware as well. So it's a really good idea to again have fuse protection or some kind of disconnect. But diffuse protection is is the preferred method to offer optimal protection.

[5m:10s] We also want to make sure that as we're terminating each of our digital signals, again, that we don't fray or bird cage the wire in any way so that we can avoid any potential hazards or short circuits.

[5m:19s] We also want to make sure that if we're using any jumpers to distribute power or distribute our neutral throughout our terminal block bus that we make sure that we secure those jumpers in place properly if they are being inserted into terminal point, so we make
sure that we properly torque each of those terminal points just depending on the type of jumper

[5m:43s] that you're actually using.

[5m:46s] And lastly, we want to make sure, as always, that we're referencing our drawings as often as possible throughout this process, that we're not missing any details, and that we can make sure that each of our signal wires is in fact being wired correctly. If we do all this, we can be confident that we've wired all of our digital signals correctly and we can move on to the next step.

[6m:7s] As you can see, due to the amount of terminations that need to be made during this step, it is important to go slowly and make sure that nothing is missed. If a mistake is made during this step, it can be very difficult to diagnose that problem later on.
[6m:23s] As always, we appreciate your interest and participation in this series and hope you continue to join us throughout the remainder of the build process. In our next video, we will move on to the wiring of the analog inputs and outputs in our control panel. So make sure to join us next time as we continue to build.
[6m:41s] For a full line of industrial control panel hardware and thousands of other products, please go to our website. For more information or other educational videos, go to RSPSupply.com, the Internet's top source for industrial hardware. Also, don't forget: like and subscribe.