View Full Version : Question about E-Stop / Remote Stop on Alpha

08-08-2005, 12:00 PM
Hello everyone,
I have a question about the proper wiring for the E-Stop button on an alpha machine. We're finishing up an upgrade from an old PRT96 to an alpha, and had a bunch of trouble with the E-Stop button. We kept getting error messages when running the SB3 software that had a title of "STOP Button is ON, or not properly connected!". In searching old posts here, I found this thread: http://www.talkshopbot.com/forum/messages/26/5233.html where Trenton said he got his machine to work by switching the green and black wires (making the left-to-right order: green black red white). I tried the same thing, and the error went away - but there's another post in that thread that indicates that the green / black pair should actually be in the ES3 and ES4 slots along with the red/white pair, rather than in ES1/ES2.

Are both of these solutions equally valid, or is one preferred? I'd like not to cause undue trouble or void a warranty by using a less-than-ideal solution.


08-08-2005, 09:16 PM
Hi Matt!

I understand that you might be curious; just as I am...

But just as long as you can operate the tool and have the E-stop working as it should... everything is OK... I believe.
I'd suggest to test it to see if it work (the tool stop when you press it) and mail support/info to confirm about the warranty thing for you to feel free of any doubts...

Still, reply if you need any more help...

08-08-2005, 11:35 PM
Hi Matt,

If I remember correctly, when I replaced the cable on my E-Stop, it consists of a push button and two switches. One switch is normally open and one switch is normally closed. Both switches are wired into the inputs of the Shopbot's controller card. When you press the button, BOTH switches change states. When you twist and release the button, both switches return to their rest position. Just as Paco said, ". . . as long as you can operate the tool and have the E-stop working as it should... everything is OK".

08-08-2005, 11:41 PM
Hi Trenton,

Reading the posts and from my own experience with the blue wago connectors , I would point the finger at the connector itself as being suspect.

As you discovered the two left pins and the two right pins each need their own switch. Each switch is part of a seperate interlock relay cct on the mother board itself. It does not matter which way the switch is wired around , just that it makes contact.

Your removing, switching and reinstalling the wiring on the connector may have been enough to set a flakey E-stop connection right.

It might be an idea to wiggle the connector while the machine is on just to make sure that it is making solid contact. Spend a little time making sure the E-stop is properly wired , an intermittent one will drive you crazy.

08-08-2005, 11:44 PM

According to the control diagram, ES1 (green) goes to position 1 and ES2 (black) goes to position 2 on the E-Stop connector block (four connector), on the control board. And, ES3 (red) goes to position 3 and ES4 (white) goes to position 4. I'm not sure that it makes any difference if you swap ES1 and ES2 wires because you're just closing a circuit thru the remote E-Stop switch - that holds true for ES3 and ES4 too. Both circuits from the E-Stop switch are either open or closed at the same time, so, circuits ES1->ES2 and ES3->ES4 are probably interchangeable too - but, I dont see any reason to swap any wiring. According to the control diagram for my Alpha, both contactors in the E-Stop pendant are normally closed - perhaps that's why they send you a new pendant with the kit. BTW, you should find a control diagram in your upgrade packet.

When I had the same problem, I tested the E-Stop switch by unscrewing the e-stop wires from the blue connector block and add a small jumper wire, 2-3" long, between ES1->ES2 and another one between ES3->ES4. This simulates a properly working stop button (actually, I just cut the jumper wires flush , pull the terminal block from the control board (with wiring in situ), and then pressed the jumpers gently onto E-Stop posts (sometimes I need to pull a few wires out of the jumper to help with the fit)). If I clear the error message I know the problem's in the E-Stop pendant. ShopBot can advise you on this procedure. In any case, remember, turn the power off before messing with any connections in the control box!

Do all of your relays pull in when you press the reset? And, do you find that the two leds above the safety relays, on the controller board, are lit? Also, the green lights on stepper drivers should be lit after a reset.

Sometimes, with my machine, I have to do a shutdown and restart of my computer to clear the problem. I usually power down the SB control cab - then power it up again and reset the controls before I restart my computer.

As Paco and Mike have suggested, you'll probably want to contact the ShopBot help desk to work thru the problem - more quickly.

08-08-2005, 11:49 PM
I read Trentons post and his name stuck.

Sorry for the mix up Matt

08-09-2005, 12:09 AM
Matt - did you install the new E-Stop pendant? Mike observed that on his machine he has a NO contact and a NC contact, but the Alpha control diagram calls for two NC contacts - and that's the way that mine is set up. I'd check to see if the pendant is configured that way by doing a continuity check on the contacts thru the green->black pair and thru the red->white pair. Finally, what I should have said is that if I clear the error message the problem's in the E-Stop "wiring circuit", not just the pendant itself. As Dick suggested, the problem could also be in the connector or wiring.