CRM schematic

[Skiroy]

Hello,
Im a entry level Automation Tech without any help at my company.

I am having trouble with a few abbreviation on the schematic for an old burroak cut to length machine. I will try to post it if I can get a good picture.

But does anyone know what "-(CRM)-" stands for. I beleive it may be the relay that powers the hot terminal block for the input switches.

Also in parralell with something labeled -(MOV)-

And the last thing is a rung which has an input that syas "PA CLIP IN POSITION 10PRX" and goes to a Output that says -(PACR)-

Does anyone know what any of these terms are?

Attached schemo.

[Skiroy]

I dont know what the (PACR) is but it must not be wired in this machine because when I look at the "Master On" switch terminals it is wired to "13" telling me that this machine has all the saftey switches in series that go straight to the "Master On" button,right?

Whats weird is when I pushed the Master on nothing happens so I suspected a saftey switch malfunction so I ran a jumper straight to the master button. But 2 things occur that puzzle me.(This is a used machine we bought so it didnt work yesturday,we got it in unknown condition)

1. The relay(CRM I assume) that supplys the hot 120V to the input buttons does switch over the coil, but it wont latch? I dont see anything else that would denergize/unlatch the relay coil because I bypassed all of the saftey switches and the e-stop by jumpering straight to the Master On Button. There is a PLC connection on the relay, but it goes into an input module so I assume it is just for status monitoring of the relay for the PLC programing. And like I said, it appears whatever (PACR) is,it is no longer in the circuit because the master on button is wired to 13 and (9) which goes to the relay coil.


2. Second thing that puzzles me is what I found trying to test all the safety switches that are in series. Assumming they are all tied to 120V,I thought I should be able to test them for 120V with a multimeter(assuming they all are working) with the red going to wire 13, that I of course I disconnected from the "Master On" button, which is the wire that should be cominf from the last saftey switch before the "Master On" button. Then I would connect the negative probe to the transformers Neutral,right? Well I get nothing. And with the 120V hot jumper tied to the "Master On" button I then get a 120V read off of the 13 wire(Not still tied to the Master On at this point). Perhaps this is a safety thing so that the saftey switches only get there 120V supply voltage when the machine "Master On", a.k.a the (CRM) relay, is latched. But Im puzzled because it seems they both need one another. The safety switches need power to even get to the (CRM) to energize it so how could the (CRM) need to be energize to supply the safety switches with 120V? Chicken or the egg?LOL!

Now there are 2 more relay next to the CRM maybe this is what Im missing? The next one is label "CR" and the third I think is for the decoiler which we dont have.

Any clarity?

[HorridHenry]

How many lights on the machine? and any meters?

[FanFan]

Hello, The MOV is suppressor. It is a protection device. The CRM a control relay. Pretty sure that the CR stands for Control Relay. The M , I am not sure about. "10 PRX" is a prox switch that is used to determined that "the PA clip" is in position. Notice that you have PACR twice in your diagram. One in a circle ( an output coil) and the other is above two short vertical lines ( an NO contact). FanFan

PS: the "M" after looking at the diagram again probaby stands for Master. As in a Master control.

[FanFan]

Your picture is not showing the left half of the diagram. X2, 2 and ground are all tied to the same point. You have a transformer at the top that is cut off. To left of that transformer should be the source of your 120 VAC. The first place I would check for 120 VAC is at 27 ternminal of the flare head guard. The NO contacts 1CRM below the Master On switch is a sealing set of contacts. FanFan

PS from your diagram it looks like there is at least one other device to the left of it. another LS?

[Al_The_Man]

The CRM stands for Master Control Relay as it is a general E-stop by the look of it, the PACR appears to be part of a Proximity switch or a batch counter or a combination of both?
MOV is Metal Oxide Varistor, it will increasingly conduct as the voltage rises above the normal coil voltage, this has the effect of suppressing the back emf from the coil, the same way a diode works on DC coils.
Normally the E-stop circuit is trouble shot by reference your meter to neutral (#2) and work back along the E-stop string to find out where the 120v stops, this will detect open limit switches etc.
Al.

[Al_The_Man]

You may find this helpful, it shows N.A. and European type symbols and control circuit examples and useful tables at at the end.
Al.

[Skiroy]

Hello, The MOV is suppressor. It is a protection device. The CRM a control relay. Pretty sure that the CR stands for Control Relay. The M , I am not sure about. "10 PRX" is a prox switch that is used to determined that "the PA clip" is in position. Notice that you have PACR twice in your diagram. One in a circle ( an output coil) and the other is above two short vertical lines ( an NO contact). FanFan

PS: the "M" after looking at the diagram again probaby stands for Master. As in a Master control.

Thankx. Yeah I dont think the "PA Prox is wired because like I said the "Master On" terminals are wire to "9" which goes to the Master control relay and "13" which the schemo shows is a the last safety switch in series. The "PA Clip Prox and PACR" which I am assuming would be some kind of Prox going to a relay for safety shows that if it was wired in that the terminal coming of the PACR going to the Master on button would be wire "29". So I dont under stand why the CRM is not latching on.

And what kind of suppressor are we talking about here? Like a thermal over load or like when you put a capacitor across a realy coil to prevent back current when the coil's magnetic field collapses?

[Skiroy]

The CRM stands for Master Control Relay as it is a general E-stop by the look of it, the PACR appears to be part of a Proximity switch or a batch counter or a combination of both?
MOV is Metal Oxide Varistor, it will increasingly conduct as the voltage rises above the normal coil voltage, this has the effect of suppressing the back emf from the coil, the same way a diode works on DC coils.
Normally the E-stop circuit is trouble shot by reference your meter to neutral (#2) and work back along the E-stop string to find out where the 120v stops, this will detect open limit switches etc.
Al.

So the MOV is probably the device in parallel with the relay coil that looks like an ceramic cap,right?

Yes there is a batch counter but like I said the Master On button goes straight to "13" which is the last safety switch in the series circuit. The PACR would be "29" but even so when I run a 120V jumper from the transformer straight to the Master On button I am bypassing the PACR,the E-Stop and all the safety switches anyways so they cant be the reason why the CRM is switching over but not latching.

[Skiroy]

One other question the transformer has a ElectroCube device tied to it,which suppresses arcing and also has a EMI filter to absorb voltage line noise. I am familiar with noise filter in audio but in an industrial application like this how is it relevant? Isit only relevant when your using an PLC or other electronic devices using IC chips? And if so why?

[Al_The_Man]

So the MOV is probably the device in parallel with the relay coil that looks like an ceramic cap,right?

See the explanation in post #6. It is a device which varies in resistance as the voltage increases.
The ElectroCube device is an RC snubber, it is an alternative method to the MOV and consists of a resistor/capacitor in series to Snub back EMF spikes.
Al.

[FanFan]

You got a lot of questions. I will try to answer some that I can. That electctro tube that you are talking about. For me that is something that I am not used to see it being used. It is also a bit odd to see the 2 2.5 amp fuse in series. It kinda looks like a gas voltage regulator tube circuit. 40 or 50 years ago I think that they were used to hold ( clamp) a power supply to a certain voltage.

Noise suppresor came in a variety of packages. You will often find then tied acros the coil of relays. They may look like disc caps, or a clear toostie roll with some components embedded in inside of it. They are used to help prevent noise spreading into surounding electronic devices.

As far as your 1CRM not latching. You need several things to happen. 1. You need to have 120 VAC at terminal 11 and 2. then you need to press Master On which will then put 120 VAC to terminal 9. IF you hold the switch on ( down).... 3. the 1CRM should pick up and 3. the Red lite bulb turns on. And then what happens 5. is that the NO contact that are seen below the Master ON switch and are label as 1 CRM will close and that will allow an alternate path for 120 VAC to be delievered to the 1 CRM and the RED Lite Bulb to remain lite. The NO contacts 1 CRM are used to "seal/ hold" The 1 CRM coil on. If you look at Al's handout and I am sure that is used many times. It is similar to a start- stop circuit. To unseal the circuit one must remove the 120 VAC. So try to figure out if you are ever getting the 120 VAC to terminal 11. BTW..You are showing only half of the print. Not sure if there is anything on the left side of the print that might be preventing your 120 VAC from getting thru.

Where are you picking up your 120 VAC when you are jumping things out? FanFan