Triac PNC3 Datum

[St233t]

Hello,

I have recently in the last few days acquired a PNC3 Triac and I'm having a few issues homing the machine,
Basically on pressing ABS/Datum the Z is travelling to the Z- over travel switch and erroring with over travel Z etc
I've cleaned the sensor checked the wiring which was rapped in electrical tape? but seems ok with the Z not homing I'm unable to test X-Y axis
I've also lowered the head to expose the sensor and placed a metal bar to the sensor whilst its lowering and the removed it with no change.
On the test screen it shows all datum with 1111 so not clear if this is correct or should this be 0000 as all the axis are away from the datum sensors and when close it is the same 1111 so not sure where to look first, I have checked the connections to the board and as X is very accessible have tested to
check for low and high by passing a piece of steel close and can see it go high from 7.9v to 8.9 volts and low to 7.9v when moving the metal away
I believe from reading here on the forum that they are 9v high correct me if wrong but I'm not sure of the correct low voltage,
I have also unplugged the Z sensor and still on test screen it shows 1111 on the datum line any ideas would be greatly received and appreciated,
Is it unheard of for all 3 sensors to go faulty at the same time ? or is this more likely a board issue though the boards look to be in great condition and no visible fault,
Side note I've checked all of the over travel switches and these appear to function correctly the test screen displaying when pressed,

Cheers
Charlie

[Martin]

Hi Charlie

It would be unusual for all three to fail at the same time.

Can you double check that the Datums are connected to PL.M on the PNC3 Control.

[St233t]

Hello Martin,
I Really appreciate the help,
They are soldered directly to the board and appear to be a very good connection I belled the wires back to the 24 pin plug at the rear of the drivers
though as they are floating resistors as I understand it not sure if they are using a common connection (3 red loop wires on the 24pin plug between datum connections) I may get continuity on all of them at the board anyway so not conclusive connections, Also correction I have checked Y+Z not X or Spindle yet, is it possible to have a dead short on one of the sensors as I mentioned they are all displayed as 1111 high/active in the test screen when all axis are away yet I can see both Y/Z go high and low admittedly not sure what low V is so bit confused by it as Test screen with the 24pin plug separated now shows datum 0111 (no connection registers high?)so if the sensors are unplugged kills my dead shorted sensor theory unless it registers no sensor as high, but having never seen one of these before all a little confusing not an electronics guy at all just like tinkering and probably enjoy this bit more than using them,
On X behind the Z angle plate there is chocolate block (screw terminal) between the X -+ overtravel switches connecting the Y datum sensor is that an original connection?
The machine is in very good condition with the original scraping on all ways still really well defined would like to have it in original spec its a nice piece
of kit and retrofitting it would be an absolute last resort.
I would appreciate any help or direction.

So small update this morning before I did anything and before powering on I wound the Z to the Over travel switch @max and ABSDatum and it homed the Z but then could not get it to repeat it so maybe a component on the board is heating up after a few seconds I'll check again tomorrow but check the test screen 1st see if it shows a change on the datum line from 1111

Cheers
Charlie

[Martin]

It's a long ago but I serviced was sent to service one & was told to cut the resistors on the board. Not sure which they were but it worked.

[St233t]

Hi Martin,

On the Datum section?
Anything look familiar ?
I could cut legs and see if I get lucky ..can always solder them back if needed ,

[St233t]

Managed to get the Triac datum to work and able to test spindle movement(though movement is another story steps wise) etc.... damnedest thing it will only datum when 1st powered on and does it every time but only at 1st powerup of the day,
I removed the spindle Namur sensor and moved it to X as this was broken/faulty (as Balluf no longer have 22.5mm sensors available GREAT!) and wired all the sensors direct to the soldered wires on the board PLM to take the "factory" (pretty sure its not all factory) loom/crimp/plug out of the equation and to be fair this did absolutely nothing.. initially so left it alone for a week fedup and went back switched it on and to my surprise it just worked ? ...."select function"!
no idea why... I did nothing else didn't even move the tray just switched power on so wiring moving not a consideration from it not doing anything but drive Z to max- so quite perplexed as to why its now doing something.... but only on initial power up back to normal after initial power datum Z- all the way ? I have used a thermal imager to look for parts rapidly heating and only the large capacitors on the power board section heat up which I imagine is normal as I don't seem to have power issues even hours after powering up.
Anyone had similar experiences ? or any idea where to look? a special handshake not documented ?
Also as a note (probably well known though couldn't find it on the forum) I did replace the spindle sensor which I moved to X due to available space 22.5mm to replace the original faulty sensor with Namur Pepperl+Fuchs NCB1,5-8GM25-N0 as these are a direct replacement(latency wise)for the spindle Namur and plentifully available stock item.
cheers
C