Hi All. I have a 2005 Haas TM-2 mill with a 20 pocket tool carousel that has been giving off some alarms. These alarms are 115 "Turret Rotate Fault" and 175 "Ground Fault Detected". Off of the stickers on the PCB the power board is 4078H Rev. J and the I/O board is 3088V Rev. A.
Alarm 175 seems to happen completely randomly. It can occur while the machine is running, or while it is sitting. It can do it once to several times a day for one day or days in a row then go days or weeks without occurring again. It can also have 'fits' where clearing the fault causes it to come back right away. These fits can be short, or last for several hours.
Alarm 115 frequency is like 175, but only during a tool change. Sometimes a 175 alarm accompanies a 115 alarm and sometimes not. Less frequently the tool changer will select the wrong tool without a 175 alarm triggering. I believe it will select a tool both before or after the desired tool, but I've only personally seen it land after. A little less commonly, the tool changer will come down when a pocket is not lined up.
I suspected that either the carousel was dirty, causing the sensor to miss-read. Or there was a faulty sensor. Or there was an intermittent fault to ground causing the sensor to be miss-read at the I/O board.
The carousel was taken apart. It appeared fairly clean, with no chips near the sensing areas. I wiped it down anyway just to be safe.
I checked all the connections from the electrical box to the motors and sensors for the tool changer, looking for frayed or pinched wires, poor crimps, or loose connections. I didn't see anything amiss.
The prox sensors for the tool changer carousel were taken out and checked against their spec. I measured a distance detection rate of roughly 3.5mm for one and 4.0mm for another. With a 2700k-Ohm resistor acting as load and supplied with 24VDC I measured a 21.8V and 21.9V signal with the prox sensor against no metal. Against a block of steel I measured 0.8V and 0.9V. All these readings seem to be in-line with spec. I accidentally switched the sensors around remounting them, but I'm going to leave it and see if the machine behave differently. It is still wired to the right place.
The brushings and commutator were checked for the carousel motor. Everything looked fine.
PCB components were searched for anything out of the ordinary. Everything looked fine except for some substance on the low voltage power supply. It could be liberally applied glue, but one area looked like it could have been a leaky capacitor. I checked the voltages at P8 on the power board, and everything checked out. A replacement is on order just to double check, but has not arrived yet.
Per the manual regarding alarm 115, Relays K9-K12 were checked visually, and look good. I did not test them electrically, but during run they appear to be operating properly. It also said to check fuse F1, but it appears to be jumpered where the fuse should be.
An additional ground was run from the ground buss in the electrical box to building ground.
Currently the machine is running through a program which just tool changes forward and backward. There is a video camera pointed at the I/O board LED diagnostic lights for the tool changer sensors. The tool changing relays above are also in view. I'm hoping to catch it during an alarm, but that hasn't happened yet. It did have a 115 alarm shortly after I started it back up, but the camera wasn't set up at that time.
I'm starting to run out of ideas for things to check. Maybe the replacement low voltage power supply will fix something or the camera will reveal something about alarm 115. In the meantime, does anybody have any ideas?
P.S. It appears neither leg off of the 120VAC control transformer is grounded. Normally I see one leg grounded. I looked in the electrical service manual for the machine, but couldn't find anything showing it grounded. Does anyone know if it is supposed to be?
Alarm 175 seems to happen completely randomly. It can occur while the machine is running, or while it is sitting. It can do it once to several times a day for one day or days in a row then go days or weeks without occurring again. It can also have 'fits' where clearing the fault causes it to come back right away. These fits can be short, or last for several hours.
Alarm 115 frequency is like 175, but only during a tool change. Sometimes a 175 alarm accompanies a 115 alarm and sometimes not. Less frequently the tool changer will select the wrong tool without a 175 alarm triggering. I believe it will select a tool both before or after the desired tool, but I've only personally seen it land after. A little less commonly, the tool changer will come down when a pocket is not lined up.
I suspected that either the carousel was dirty, causing the sensor to miss-read. Or there was a faulty sensor. Or there was an intermittent fault to ground causing the sensor to be miss-read at the I/O board.
The carousel was taken apart. It appeared fairly clean, with no chips near the sensing areas. I wiped it down anyway just to be safe.
I checked all the connections from the electrical box to the motors and sensors for the tool changer, looking for frayed or pinched wires, poor crimps, or loose connections. I didn't see anything amiss.
The prox sensors for the tool changer carousel were taken out and checked against their spec. I measured a distance detection rate of roughly 3.5mm for one and 4.0mm for another. With a 2700k-Ohm resistor acting as load and supplied with 24VDC I measured a 21.8V and 21.9V signal with the prox sensor against no metal. Against a block of steel I measured 0.8V and 0.9V. All these readings seem to be in-line with spec. I accidentally switched the sensors around remounting them, but I'm going to leave it and see if the machine behave differently. It is still wired to the right place.
The brushings and commutator were checked for the carousel motor. Everything looked fine.
PCB components were searched for anything out of the ordinary. Everything looked fine except for some substance on the low voltage power supply. It could be liberally applied glue, but one area looked like it could have been a leaky capacitor. I checked the voltages at P8 on the power board, and everything checked out. A replacement is on order just to double check, but has not arrived yet.
Per the manual regarding alarm 115, Relays K9-K12 were checked visually, and look good. I did not test them electrically, but during run they appear to be operating properly. It also said to check fuse F1, but it appears to be jumpered where the fuse should be.
An additional ground was run from the ground buss in the electrical box to building ground.
Currently the machine is running through a program which just tool changes forward and backward. There is a video camera pointed at the I/O board LED diagnostic lights for the tool changer sensors. The tool changing relays above are also in view. I'm hoping to catch it during an alarm, but that hasn't happened yet. It did have a 115 alarm shortly after I started it back up, but the camera wasn't set up at that time.
I'm starting to run out of ideas for things to check. Maybe the replacement low voltage power supply will fix something or the camera will reveal something about alarm 115. In the meantime, does anybody have any ideas?
P.S. It appears neither leg off of the 120VAC control transformer is grounded. Normally I see one leg grounded. I looked in the electrical service manual for the machine, but couldn't find anything showing it grounded. Does anyone know if it is supposed to be?
