PRTAlpha Z-Zero Plate Stopped Operating

[mike]

After 5 years my Z-Zero Plate stopped operating. I have checked wiring...red into +5V, black into Input #1, green into ground. Continuity checked okay from alligator clip to end of wire at terminal and zero plate to wire at terminal. Wires disconnected from terminal during testing. Setup has not been changed from Input #1. Reconnected wires into terminals...Input #1 light does NOT illuminate with clip on spinde and bit in contact with zero plate. Clip to zero plate...no light. Can anyone advise me as to next step? Any assistance would be GREATLY appreciated...Mike

[jerry_stanek]

Can you use a meter to check the continuity of the wires. It sounds like a broken wire

[mike]

Yes...I have a meter and checked the continuity of black and green wires from the clip to other end at the terminal block and the z-zero plate to the other end at the terminal block. I disconnected the green and black from the terminal block to ensure I was only checking the continuity of the wires. Both wires checked good.

[Brady Watson]

Make sure you have a good ground to the chassis of the machine. If you don't, the plate won't work. You can also run a ground to the control box from the chassis as well. Try it real quick and see if that's what it is.

-B

[gene]

If you are using a coated bit the connection to the bit and the clip may not be making a good connection , especially if you are using a router and not a spindle. some bits come with a protective coating also . . especially if the continuity on the wires checked good. what i would do is hook the clip to the bit with the bit touching the z zero plate disconect one of the wires at the terminal block and check for continuity thru that to see if the circuit is complete. if the circuit is complete then it has to be on the settings somewhere . hope this helps.

[jerry_stanek]

He posted clip to plate did not produce a light. Try UR command and reset your default settings.

[mike]

Brady, Gene and Jerry...thanks for your input!!! I'll try your suggestions.

[mike]

Wired ground to classic...Reset defaults using UL...no change...#1 input light will not illuminate. I just noticed that I have a narrow vertical yellow line in the #3 input. I never noticed it previously. Is this normal? Should I contact Shopbot tech. support?

[jerry_stanek]

Put the ground wire from the plate on another ground pin. I had one ground pin that is flaky and only works sometimes and that was the one that my zero plate was hooked up to I moved it over and haven't had a problem since.

[gene]

I think that is the light that tells you a lost conn . Hit the reset on the control box to clear it and you should be good to go

[mike]

Hit reset...narrow yellow line remains in #3 input. Just noticed that I have always had the red wire from the Z-zero plate cable connected to the +5 input on the far right terminal. On the left near the E-stop is the +5V stud. There is not terminal block with screws, so I have never connected anything to that post. Because the Z-zero plate and clip only involves the black and green, plus the plate has worked properly for years, I don't think the red wire is involved...Right? I looked in my literature and didn't find any explanation about the #3 input light. Can anyone tell me about it? I sincerely appreciate all your input.

[garyc]

Mike...
Yellow Line in a green circle is normal position for a normally open limit as in the PRT. This would not be correct for a PRS machine.

The red +5v wire that goes to the ZZero plate or connector is to power the probe. It is not needed for normal operation of the ZZero plate

[gene]

I think he has a PRT Alpha and not a PRS

[mike]

Moved ground...no light in #1 input. Has anyone ever detected the narrow yellow line in #3 input light? I have really messed up things. Machine has lost positions. X and Y moving 50% of specified move directions. When I mess up I do a good job. Of course, this occurs just as I'm scheduled to mill MDF doors for a local cabinet shop. I'm digging out the Shopbot Setup instructions...haven't looked at that in years.

[Brady Watson]

Don't panic.

Ignore the Input 2 & 3 lights.

Get into SB3 and run the UR command. Hit Enter 3 times. Under 'Older ShopBots', select PRTAlpha (if you have AS98AA-T7.2 motors, choose the one that has 7.2 after the name). This should fix your movement distance.

If output 4 flashes, use the VN command to change "Switch#4 STOP Type" from normally closed to normally open.

Then do the following:

Pull out the Zzero plate wires from the blue screw terminals. Move the ground wire to it's own discrete ground terminal somewhere down the line on the blue terminals (don't be afraid to strip insulation back to make wires a little longer) - then make sure ground wire and black input #1 wire are fully seated in the blue terminal strip AND if you removed the blue terminal blocks from the board that they are not off a pin...make sure they are where they are supposed to be on the board.

Want to get the Zzero working for SURE? Run a ground wire from the chassis of the machine (anywhere...make sure you have a good connection) back to the control box. Secure it on any open ground terminal on the blue screw terminal strip. If it STILL doesn't work, you've got a broken wire somewhere...and a very rare possibility that your control card is flaking out. It's a pretty simple circuit.

You can test to see if the card is flaky by putting a wire in Input 1 and short it out to gnd for a moment while looking at the input 1 light in SB3. If it works, then your issue is from the control box out to the plate.

-B

[mike]

Guys...thanks so much for the input. After I complete staining this chest, I'm going back to my bot and implement these suggestions.

[jerry_stanek]

Guys...thanks so much for the input. After I complete staining this chest, I'm going back to my bot and implement these suggestions.

If you lie out in the sun your chest will tan real nice just be careful so yo don't burn.

[mike]

Left myself open for that one...Jerry quickly jumped in and took his shot. I guess I need to be a little more specific..."blanket" chest. Jerry, thanks for keeping me on my toes. Now back to the bot... Z-zero is still inoperative. Got the correct movements for a short time. Now when I power up the control panel and press "reset" nothing happens. I think those birds that built their nest in the back of my shop have moved into my control panel. This "reset" issue occurred a few years back. I can't remember how we corrected it, so I'm going to dig into my old notes.

[Brady Watson]

Push the magnetic contactors in while pressing reset button - after you have determined that the box is getting power.

Why is the Zzero plate still not working? Did you make a jumper wire to go from input 1 to ground yet? Did input 1 light up?

-B

[mike]

Verified control box is getting power. Pressed magnetic contactors while depressing reset button...nothing. After turning on/off switch to on, then depressing reset button, you can here a slight click, but nothing. No click after depressing reset button again. i haven't located my notes from first time this occurred a fews back, so I'm starting from zero. I'll check the history on the forum...maybe someone has experienced the same issue.

Regarding Z-zero plate light...disconnected green and black wires from terminal. Connected jumper directly between #1 and GND...no light. Connected jumper from #1 to another ground in cabinet...no light. With green and black wires disconnected from terminal block, I attached clip to plate. Checked continuity at ends of green and black...good. This test isolated wires, so the wires from clip and plate are good...right? Appears we have an open circuit from the terminal block to the light...right?

[mike]

Oh yes...after correcting the position issue earlier, I shutdown power in the box to open the door and check the z-zero circuit. I moved the green wire to another green. Then I turned the on/off switch to on and pressed the reset button...nothing. The fuse is good.

Guys... thanks for all your input. I think I have attempted to perform every recommended test. The position issue was corrected prior to the reset failure. I had to tell the system that I was running a 96x48 7.2 instead of my actual 96x60 alpha, but it's working.

[gene]

Have you talked with shopbot? I am curious as to what is going on

[mike]

Yes...I talked with ShopBot. Tech is reviewing and planning to email a few other tests for me to perform. I'll let you know the results. Thanks for all your input.

[mike]

Received troubleshooting recommendations from SB. Cycled E-stop switch several times to ensure spring wasn't stuck...no reset. Pressed reset button while watching 1,2,3 red LED counter...Slight click on first pressing of reset and LED goes out. Released resest and counter starts again. Second press no click, LED goes out...released counter starts. Power down, then back up...same results. Checked incoming DC voltage across 24+ & CM- and 5+ & CM-, readings were 26.4 and 5.5 respectfully. Is the 26.4 DC a problem? I don't know the specificatons or tolerance range. No reset.

Reported results back to SB support...waiting for other troubleshooting instructions.

[mike]

Gene...just an update. Christian and Chris at SB support are working the failures. Both guys have been excellent in communicating with me. The Z-zero plate failure has grown into a return communication error between the computer and control panel. Those guys may never answer another email from me. I'll keep you updated. This failure may be one for the history books.

[gene]

I hope they will record what they did to fix the error and what caused it. Sometimes when i reset my bot i hold the reset button in and GENTLY tap on the outside of the reset switch with a wrench . Then the reset , resets itsself. i think that mine has a connection issue at times , or its possessed!

[mike]

I think they will . I haven't heard from anyone today, so I think they are digging deeper into the reset issue. Chris and Christian have been great. I have a longtime friend who just purchased a Shopbot to donate to Anvil Tech. School in Kentucky. He was very impressed with my machine and thinks it would be an excellent method of introducing the kids to CNC. I delivered SB quote to him yesterday. During my visit he ask how my machine was running...I had to tell him it was down. He's monitoring my tech. support. In fact, he called today to get an update. I'll keep you posted.

[Brady Watson]

Mike,
Have you tried running UI and re-flashing the firmware to the control box? This will sometimes clear out and reset troublesome input switches if the problem resides in the controller.

-B

[mike]

Yes, we have. Chris at SB walked me through that procedure yesterday. I have been installing columns in a clients bathroom today, so I haven't been in the shop to check from the blue terminals back through the circuit. Haven't heard from SB today. I would think a jumper directly across the terminals at the black and green wires would have illuminated the light. I think that would be a direct connection to ground. I'm lost as to next step...just waiting from tech. support.

[mike]

:D Chris and Christian at SB just won GOLD. My PRT Alpha is up and Z-zero running. We could never get a light on #1 input. So, Chris instructed me to move the black wire from #1 input to #5 and update the ShopBot Setup Z-zero with #5 input. Z-zero routine ran correctly. Ran the cut circle routine above the table. Machine moving great. Another thing, Chris had me to download the latest version of SB3. Thanks so much for everyones input. I normally do not post to the forum, but I hope my postings of this experience will help anyone faced with the same or a similiar situation in the future.