Drive alarms

[nervis1]

Mazak QT-8 T2 control.

I was getting axis drive alarms after I started using this lathe, x axis first then z axis a week later, The alarms are 13 and 14, signal lost or out of range, position error out of range. I replaced both resolvers but this has not helped.


The problem seems to occur only when the machine is idle or jogging. I can start up and run a program 10 times in a row with no problems.


What else could it be?

Is there some adjustment that needs to be made to the new resolvers?

Thanks for any ideas.

Dave

[Al_The_Man]

Dave, The overall machine status and servo's can be observed on the Display, select until you see DIAGNOSIS. Push the button just below the Diagnosis message and the display should show ALARMS I/O CHECK M-MONITOR etc
Lower down should show DROOP GRID GAIN PHASE VERSION
for the X,Z,C axis
If you need to check the servo data, the Droop or Following Error should be 0 when no motion, this adjusted by VR() on the servo PCB ( the manual does not show which VR is maybe the board is marked)
Gain:
Check this reading while moving at ~1M/Min, The reccomended should be 33 and is adjustable by VR2 on the servo amp pcb.
Phase shows the difference between the reference signal from the CNC and feedback from the resolver: No adjustment.
I/O monitor is the status of all the machine I/O
Grid is the dimension from the home switch to the next grid signal.
Al.

[nervis1]

Oh that helps a lot, at least something I can try. The droop on both axis fluctuates at idle by one or two numbers ie: -3 to -4 or 5 and back.

So I should turn the VR pot on the PCB servo board till that stays still?

Re the Gain how do I get the machine moving at a constant rate? Is there a test test program I can use?

[Al_The_Man]

It's been a long time since I did this, but I don't remember if the VR pot for the droop was just VR or if it had a VR#. But you do adjust it for zero when axis not moving.
Also I don't recall wether you can program a MDI move or just jog at a measured rate after going to the diag, screen for VR2. The manual says check it while moving manually. So I assume you set the jog feedrate ahead of time.
I am not sure wether this manual is still available, it was compiled by one of the Mazak service engineers at Florence KY in 1986. for the T2 T3.
Al.