[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

[Al_The_Man]

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.

I did not look at the schematic for the Electrocube as now they are associated with RC snubbers, but rechecking the schematic reminded me they did make a Gas tube regulator (almost as old as me) :tired: that was the forerunner of the more modern MOV.
Al.

[Skiroy]

Can anyone guess as to where wire 11 is going. My power problem is related to this. I know it is one side of my CRM interlocking circuit. I get how it works now. the relay has 3 contactors and the second one is my interlocking rung or loop. The top wire of this contactor goes to "9" which goes to my CRM coil. So "11" should be live at the CRM so when I push my Mastor on 11 connects to "9" energizing the coil and keeping the CRM latched. But "11" goes out into the machines wiring which is all routed in the frame and makes it impossable to trace. Looking at the schemo can anyone gues as to where it might go?


Possibly does it tie into wire "13" coming off the last safety switch,where 13 ties in with "11" and then goes to the "Master On" button? This would make sense why "13" is dead when I would think it should be live without the CRM latch and then becomes live when I jump 120V to "9". Because "9" is then sending it through "11" into "13". Is this correct?

I figured "when "13" became live that it meant that all my safety switches we intact but if I am right about "11" tying into "13"( By the way I was told the the PACR is not installed on this machine) then it would not only explain why "13" goes hot when I force the CRM on but it also indicates that more than likely my issue is one of the safety switches.

Any clues or insight AL? I guess "11" being tied into "13"(which goes to the "Master On" button) from the last saftey switch and then also goes to the CRM would would be put the CRM latching contactor in parralell with the Master on but the way the schemo shows right?

[Skiroy]

Hey Al also. I think the other side to this machine's issue is the PLC. This machine is old and was sitting for month with a dead battery. The PLC is one of the oldest ones I have ever seen. It is a "mini"<-yeah right, 2/15 and came with a cassette tape with the program backed up one it,which undoubtably is useless.

But my question is,do you know if these things have memort or EEPROMS in them that would store the program in it like a SLC 500?

And do you know the module needed attempt to put the program back on it with the cassette tape and any operator instruction?

[Al_The_Man]

If PACR is not on the machine, where does power stop when you measure from 2 to 11 or 13?
The 2/15 has battery backed memory IIRC, I had the PC program for back up on these, I have not seen the tape unit for eons.
Do you have a hard copy print out of the ladder?
Al.

[FanFan]

Here is a link to some info for a A/B PLC-2:

http://literature.rockwellautomation...m002_-en-e.pdf

It might give you some info and suggest some options. The plc-2 used to have industial terminal (I think) that could be used to look at the plc program . Also the tape, if it looks like a slight fatter but smaller cassette tape I think that uses a data catridge recorder to load the plc program.

If you are lucky there might be software that can be used with a PC or Laptop. They may replace the data cartridge recorder and industrial terminal.

As far as wire 11. Per the print it looks like it is fed by the N/0 contacts of PACR. The print show them as hardware... a coil and N/O contacts. If the PARC coil is pickup then the N/O contact would close, and then 120 VAC could be supplied to wire # 11 on the Master on switch. What might be happening is that the PACR coil (hardware) was replaced by a PARC coil ( software). That software coil would be inside the PLC. I would look at the plc's output modules and see if there is a connection to the Master on switch. I don't think that you have ever mentioned the high speed guard 1 LS. That alsomay be a missing link and part of the puzzle.

Good Luck, FanFan

[Skiroy]

If PACR is not on the machine, where does power stop when you measure from 2 to 11 or 13?
The 2/15 has battery backed memory IIRC, I had the PC program for back up on these, I have not seen the tape unit for eons.
Do you have a hard copy print out of the ladder?
Al.

Thankx guys I figured it out. This thing had a uncoiler installed previously that had additional safety switches in series with the ones in the schemo so there was a some wiring that didnt allow the current to get to the Master On button

I got it to latch on and bring power to the PLC and motor starter. When I push the buttons I see the PLC input modules trigger. According to the program print out it should be starting the motor. My instincts are telling me that because the batteries were dead and this thing was sitting that the program is corrupted.


Al what is "memory IIRC"? Without power source or batteries how long will the program stay in memory in this thing?

[Skiroy]

I just verified that there is no EEPROM in the slot and according to documentation the EEPROM is either faulty or uninstalled if the memory LED stays lit,which mine does. The batteries read 1.47V is that close enough to 1.5V to be good? There were corroded though and the Low Battery light was flashing.

So without power,batteries or a EEPROm how long will the program remain in this unit's memory?

[Al_The_Man]

IIRC= If I recall Correctly:
You will see the inputs register even with no program, the test would be to see if any outputs come on confirming the program was running.
Rather than try and find the loader and get the 2/15 running I would be inclined to swap it it out with another PLC of your choice, it may take a bit of reverse engineering to figure out the program, but probably cheaper and quicker in the long run.
Al.