e-stop pains on millport, I need help

[dannystooblue]

Here is a picture of tha back side of my control panel. http://www.cnczone.com/gallery/showp...o/4726/cat/500

The control tells me the e-stop is pushed in, I have cheched both e-stop buttons and they are both working fine. I went farther to check on the plug you see in the pic. from left to right i checked the voltage from the post labled "+24v" and the e-stop with the button out, it is showing very high voltage (120dc), i then checked the e-stop to ground, "0vdc", then contunity from e-stop to ground and they are common. then checked the 15vdc and it appears to be ok. I do not think i have an e-stop problem, i believe i have a voltage problem maybe? i have taken other pictures of the power supply where it is feeding the "+24v" post on the board, but still havent sorted the pictures.

For reference:
1) this is a 10hp millport, vintage of about 1988
2) I just rebuilt the powersupply to the main drives because the transistors were fried
3) I have had the machine moving since then
4) I do not know much about electronics, I can check voltage and such, but can not read electrical drawings.
5) I do have some electrical drawings for this machine, but they are greek
6) This machine is running with a 20hp rotary phase converter, I do not think this power supply is running from the "generated leg"

[One of Many]

I think you will need to show the schematic to give us an idea what all is incorporated in the E-stop circuit. Whether it is seperate from over travel switches and if it is positive or negative logic at the E-stop input. The 120vdc sounds like a cross connection to a motor supply or another failed portion of the main supply. Typically the control voltage should be 24vdc(relative to ground) and you should be able to test meter that as each E-stop is "normally closed" when not active, to carry the loop back to the input.

Since you have been working on it, others looking at the schematic still don't know how it is really wired or capable of confirming its integrity therein. Specifically disconnecting things until that 120vdc is tracked to its source without completing the loop and cooking an input(if it hasn't already done so).

At least check each side of the switches when they are pushed in(open) to see what is there. Then you should have a better chance in tracking the voltage rise to a cause. I see no wire numbers, so that makes it even tougher!

DC

[dannystooblue]

I will try to get the drawing in a pictre format, it is on a "C" sheet so scanning it is outside my ability, I may have to redraw it. The e-stop is not really tha complicated of a drawing though. I have found an error in my earlier post, the voltages are wrong in the post, the meter i was using was damaged and not working correctly. The voltages are as required. Most of the wires are numbered or easily tracked... atleast as far as the e-stop goes. I have checked the wires and connections to make sure they were good and tight, they seem ok. The e-stop buttons seem to be ok. There are two other things that the e-stop wires go to, one is a relay board and the other to a board I have no idea about. I will get as much info as i can in the next day or so.

Danny

[dannystooblue]

this is the photo of my e-stop.

The only work i have done is on the drive units power supply, it doesn't get any power turned on to it until the e-stop is corrected. By hitting e-stop the power to the drive boards is cut off.

after posting this i realized that the photo didn't do well uploading here, if anyone can help i can email you the photo.

Thanks, Danny

[dannystooblue]

Here is a pdf of a re-draw I did tonight on the thing. I don't really understand it very well.


Danny

[One of Many]

As drawn, the E-stops take +24v to pin 16 of the 37pin connector and energizes Relay 16(although the drawing does not reflect this through the pendant E-stop). The OT limit switches go into pin 12 and should also energizes Relay 15. Relays 15 & 16 have contacts that activate the DRIVE ENABLE Relay 9. Relay 9 has contacts that activate Relay 1 and Relay10, which we do not know what their respective contacts energize. Presumably power to the servo amps?

You should see +24v at pins 12&16 on the 37pin connector and verify the relays 15&16 contacts close to energize relay 9 by seeing +24 at wire #91. Then verify there is +24 at wire #89 to energize relays 1 and 10.

If this all pans out, then something with the inputs beyond pins 12&16 at the 37pin connector is not seeing the E-stop signals.

DC

[dannystooblue]

OK, I have checked what i could of this. Inside the Pendant with TB18 i check 24v on pin1, 0v on pin2. If I read what you sent correctly I should have see 24v on pin2 which would feed pin16 on the 37 pin connector as well as relay 9. there is 24v on pin 12 for the over travel, it checks fine.


relay 15 is the only one energized at this point.


Danny

[One of Many]

It looks like you have made some discoveries in troubleshooting where the fault lies. Be that broken wires, bad contacts, poor solder joints or burnt board traces. It is starting to look local to the pendant, but also look for modifications not shown on the schematic. Like safety interlocks or pressure switches etc.

I've even found where people have put hidden key lock switches to prevent others in the shop from using their treasured machines. Buying used machines with unknown history, you don't know what may have been removed as external equipment. Often this leaves wiring incomplete at a terminal block or wire nutted in the cabinet somewhere in the snap track.

If need be, you could jumper 24v to the input around the E-stop, just to confirm everything else is functional. Then finish up with the hunt to correct the source of the problem.

DC

[dannystooblue]

i pulled the e-stop wire from the pendant board and jumped 24v to it, all the relays came on just fine but the motor drives did not come on. all of the correct relays powered and made contact up through 19. The large relay that powers the drive board power supply did not see any current. I did not have the air on either this time, this may have been the final thing missing to get the drives on.

with this all the case it looks as thought the board in the pendant with TB18 on is could have a problem? I looked and did not see any noticable burnt traces.

I have had the machine running before, when i bought it they couldnt tell me what was wrong with it. With some time and help on here I found the power supply for the drives had dead transistors, 3 which i replaced, then everything worked... except i have no idea how to run this machine. I have lived a somewhat sheltered life with fanuc and mit's controllers... oh, and do eazy tracks count?


Danny

[One of Many]

In many cases where you are forced to use the "black box" inference, you will also be forced to troubleshoot from multiple ends of a circuit. This is all in effort to narrow the fault to a specific area of the control. It won't do much good if you know certain conditions need to be met(like air pressure) and expect a different result. Unless you have accounted for it by jumpering it out. The biggest hurdle is not having access to what goes on inside the "black box" based on inputs to control what appears to be unrelated outputs.

On those terms, look at what drives the big relay and work backwards?



DC

[dannystooblue]

I expect the lack of air is the reason the drives did not power, the control screen still said there was an e-stop issue. In the past, when it was running, it had a separate alarm for each the e-stop, over limit, and low air pressure. I will try it with air pressure to eliminate that possibility as well though.

Danny

[dannystooblue]

Next thing I did was hook the air back up and jump power to the e-stop. For a moment the drives came on but were faulted. I hit the E-stop to reset them and they would not come back on. the entire time the screen read "e-stop pushed hit reset".


working backwards from the main drive relay will take a little bit. I will look for the scematic showing it as well. All of the drawings were folded and placed inside the machine door... they kepth the controller door open when it got really hot outside!


Danny