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QT-10, T2-CAM, Troubleshooting X & Z axis drive not ready (TR8A-L & TR43B)

cwtoyota

Cast Iron
Joined
Feb 11, 2010
Location
Washington State
QT-10, T2-CAM, Troubleshooting X & Z axis drive not ready (Solved!)

I started this post, realized I had written a novel, so I made the short version and I'll reply below with more detail.

I'm looking for troubleshooting information for the TR8A-L servo drive, TR43B top-board and the FX-61 board.

Specifically I need to know what signals the servo drive and top-board must receive from the control for the servo drive to start up and run.
 
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The long version:
I started up my QT10N yesterday morning and when I pushed the jog-stick to home the Z axis I got the NC alarm for Z-servo excess lag. Restarting the machine and trying the X axis gave an error there too.

So after a little checking, I found that the servo drive for X & Z is not being made ready.
Everything else on the machine works fine. Tool-change, spindle, quill, coolant, etc.

Further investigation found the drive contactor is not closed and there are no errors displayed on the drive or the CRT.

The drive is the TR8A-L with top board TR43B.

There are five small relays with green LEDs on the top-board. The drive manual confirms that these five relays should all be closed (LEDs should be lit).

I have the NORM relay closed (LED on), while relays RA1, RA2, SVON X and SVON Z are open (led off).

I've checked the main power to the drive @ U,V,W and I've checked the control power 100V AC @ R3,T3.
I have +24Vdc from AL1 to AL2 when the E-stop is in the run position and they are open when E-stopped.

I have checked the wiring from the top-board (two Honda connectors) down to the FX-61 card in the NC unit. That seems to be fine and it's in good shape.

Finally, I swapped the complete drive and top-board for identical units and have the same issue... Drive is not being made ready.

I am fairly confident that the machine is not passing one or more important signals to the drive.
I am suspicious of the FX-61 board in the NC, but I don't have any information to troubleshoot it.

I do have a few quality digital multi-meters an oscilloscope and plenty of patience...

I haven't been around the forum much lately as I've been running my shop and going back to college at the same time. Hope all you fellas are doing well.
 
If one of you fellas can take a multi-meter set to volts DC and measure the voltage between AL1 and AL2 on your TR8A-L servo drive with the machine on and ready to work, that would be a big help.

I think the 24Vdc I have there is correct, but would like to confirm the value.



Per the TR8A-L manual I have, there's supposed to be a sawtooth wave on check pins 16 and 18 of the top-board.

The scope shows a clean signal on both axes.

CP16(Blue) CP18(Pink).jpg
DS1Z_QuickPrint3.jpg
 
I have found the problem and I'll describe it below to hopefully help out the next fella.


Per my above suspicion about the 24v signal across AL1 and AL2 I went digging through the wiring diagram.

The sheet with the transformer connections shows that OHT1 and OHT2 are closed-circuit (they are connected together in the transformer) until the temperature rises above 120°C.

I pulled the AL1 and AL2 wires off the terminal block at the servo drive. They show open circuit using a digital multi-meter.

This could be a chopped piece of wiring, a loose connection, or a problem with the thermal circuit breaker in the transformer. I haven't investigated that end yet since there is a LOT of sheet metal between me and that transformer.

For a quick check, I connected a jumper between AL1 and AL2 terminals on the drive and the machine works as it should.

Now I'll pull the cover off and check continuity across the OHT1 and OHT2 terminals on the transformer.
If the circuit is closed at the terminals on the transformer, it's a wiring issue.


Issue Found.jpg
 
I can’t get my Mazak t2 to home in either axis I have the same drive. Did you just jumper al1and al2 and it homed? Thanks for any help.
 








 
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