Need Help!- Mazak VTC20B

[Morse Eng]

We have a Mazak VTC20B that is giving us some grief.

First some background....

The original problem with the machine was a ground fault in a Mitsubishi power supply (MDS-B-CV-150) that was replaced with (MDS-C1-CV-150). In the process of diagnosing this problem and arranging a replacement the machine was powered down for about 4 weeks which I feel has led to our current problem.

When we powered the machine back up the new power supply and all the servo’s displayed the correct codes etc. The trouble begins when we power on the control (Maztrol M Plus). Shortly after the control is switched on we get 2 alarms, the first is [03 Emergency Stop] which cuts all power to the power supply and servo drives and sends them into fault, I believe this alarm however is caused by the second alarm. The second alarm is [113 Over Travel +X] which seems very obvious but I’ll be damned if we can correct it. Several things are hampering us in resolving this.

• Due to the emergency stop alarm we have no power at all to the drives so we can’t move the axis via the jog buttons or handle.
• From looking over both the machine and wiring schematics there does not appear to be an over travel limit switch only a home switch for each axis.
• We thought perhaps it was a “soft” over travel fault but that appears to have a different alarm code [101 Soft Limit +X]

The guy who usually services this machine thought it was related to this soft over travel and suggested we adjust the M8 Machine Parameter to 99999999 and cycle the power to the control however when tried this the data we entered was not what was displayed as the new parameter value. To explain this better I’ll give a couple of examples.

0 -> 0
1 -> 1
2 -> 2 .....
32767 -> 32767
32768 -> 0
32769 -> 1
99999999 -> 92299519

We found this to be very odd and believe this to be part of our problem.
Any insight you guys could provide would be great. My apologies if I have gotten any of the terminology incorrect as my background is mainly in electrical and automation.

Regards Matt

[psychomill]

113 is an over travel alarm usually associated with barriers or safety zones. You can check parameters I2 and I3 to see if they are set somewhere strange. I believe if I14.2 can toggle this function on/off.

Generally, neither 101 or 113 will set off an E-stop. If I remember right, if you hold the RESET and MF1 button at the same time, then you can move the axis (keep holding the buttons). On M32 and M+, I think there's actually a second button to hold to get the machine out of E-stop. If that's the case, then hold all three while you move the axis out of the way. For some reason, I remember you needed 3 hands to do this....

Why your data display changes I'm not sure. M8 is active immediately, don't need to toggle the power.

[Aldoj]

Hi, have you got your machine fixed yet ?
What was the original value in parameter M8 (normally 10000) which is equivalent to 10mm of overtravel.
Have you tried matching the hard copy parameter sheet with what is actually in the control to see if there are massive differences, if there are your parameters are almost certainly corrupt and you may have to re initialise and re load them.
You have also replaced an MDS B unit with an MDS C unit, the MDS C unit is a newer version and sometimes the firmware within the unit is not completely compatable with the older cnc controls , but there are ways round this. if you still need help let me know and I will see what I can do.