Need Help!- Bridgport EZ-Path Problem

[M.G.Machinist]

We have a Romi Bridgeport EZ-path lathe that freezes up at the end of the home sequence. It homes the X ok then it seems to home the Z but it never come out of the homing screen. We have to reset the machine to unfreeze the screen. Anyone have any ideas?
Thanks for any help,
Matt

[One of Many]

I couple things to try besides checking fuses or circuit breakers etc.

Push the Z axis about a foot or so towards the chuck when the machine is off.

Boot the control and home the machine. If the Z moves, then manually trigger the homing switch early. If the machine homes there, it may be a simple adjustment of the switch or cam.

If the Z does not move, then either there is an issue with the servo amp or motor. During the homing cycle, monitor the LED indicators on the servo amps. See if something is different between the two amps before and after homing.

You can swap the cables and connections between servo amps to see if the problem moves to the other axis. I'm not a big fan of swapping axis motors, but if they are the same, it is a last ditch option.

Some machines had a utility on the hard drive that allows I/O diagnostics. I cannot recall the name off hand. EZSPS or something along that line.

Short of that;


Someone qualified, could check that the homing switch is getting to the control AUF card JP14-1B or JP14-2B. I don't think there was an LED indicator, so it may need verified with a multimeter while someone else is triggering the switch.

If all is well with the home switch, next check the encoder signals at the AXZBOB card JP4. This will be done with the machine on, but not homed yet. Best to use a logic probe or O-scope as the Z screw is rotated by hand.
JP-4 pin x =
1=A-
2=A+
3=B-
4=B+
8=Z+
9=Z-

6=+5v
5=0v
7=0v shield
10=0v shield

Calling in a good local tech would be less risky than attempting this on your own, if beyond your experience. Just don't create more problems than you really know how to solve!

DC

[M.G.Machinist]

DC,
Thanks

[M.G.Machinist]

DC,
Thanks for the reply. We have checked fuses.

We manually triggered the switch early while the Z was moving. When we did, the Z stopped and the position on the screen changed to 0.0 but the screen continues the say Homing Axis and nothing will work. We have to reset the machine.

We had a tech in here looking at it and I'm not sure what all he has checked but I'm trying to find out.

We are going to try switching cable and connections on the amps and see if the problem moves.

Thanks again,
Matt

[M.G.Machinist]

We tryed swapping the servo amps and the problem moved. The problem seemed a little different, it was giving us an error - Following Error Limit Exceeded. We are going to get a new servo amp and see if that fixes it.
Thanks,
Matt

[One of Many]

A following error is usually associated with encoder feedback, but could also be loss of tach feedback or the motor not moving at a velocity as commanded.

Well, now that I think about it, if all cables and connections are not swapped at the amp, there could be a signal missing when the axis moves.

DC

[JoBwan]

Originally Posted by M.G.Machinist We have a Romi Bridgeport EZ-path lathe that freezes up at the end of the home sequence. It homes the X ok then it seems to home the Z but it never come out of the homing screen. We have to reset the machine to unfreeze the screen. Anyone have any ideas? Thanks for any help, Matt

We have several of these units in our shop. One thing to check is wiring inside the wire track ( behind the tailstock area). We have had to call in a company called DB-2 from Detroit area to repair it properly. We have found broken wires and spliced them for a quick fix. DB-2 will also help you over the phone extensively to keep from having to make a service call. They are very helpfull. Just an idea.

[ganeshnk123]

You can check the output of the encoder with a oscilloscope.
Or you can exchange the X and Z motor and see if the problem follows the motor. This only if it is the 1st generation EZPATH that has identical SEM motors on both X and Z axis.

I had same issue for same machine till date machine working as per requirment
Reagrds,
Ganesh

[M.G.Machinist]

this ended up being the hard drive or a software problem. we put in a new hard drive and loaded the software and the problem is fixed. Thanks for all the help.
Matt

[minardsanders]

I have noticed that we have to set the carriage close to the end of the table, three to four inches from where home is when we shut off, otherwise it will show travel stop errors not set. see if this works. minard