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QT8 with T32-2: Spindle Start Misoperation alarm

carbonbl

Cast Iron
Joined
Apr 15, 2016
I'm getting my '89 QT8 with T32-2 back up and running after it was sitting for a while and lost parameters. I restored parameters and everything seems ok. After I start the machine up and home it, I'm getting alarm "250 Spindle Start Misoperation" when I try to run the spindle (spindle jogging works fine). The machine was not throwing this alarm before this recent downtime. From what I was able to read, this is an interlock on the spindle that can be set by multiple conditions. While the machine was down I did replace the chuck clamp/unclamp switch which the the previous owner had somehow rewired to be linked to the keyed ID/OD switch when they couldn't find a proper replacement. The wiring diagram was not much help with this but I was able to put a new switch in and rewire in a way that "seems" :rolleyes5: plausible based on the existing wires. The switches appear to be functioning correctly in how they work the chuck but maybe there is something still wrong with the wiring? The clamp/unclamp lights on the panel are not illuminating. I did go through the R49 chuck parameters and made sure it is using a timer to set chuck clamp/unclamp and not looking for prox switch signals.


I also am not sure how to check the PLC bits and have no ladder diagram for this machine, so I'm basically guessing as to what could be locking the spindle out. Does anyone have any diagnostic advice? I'm guessing it's something simple like a wrong parameter or a minor wiring/switch issue but I'm not sure what else to check before I call a tech.
 
Last edited:
open/close confirmation maybe

either the prox switches are wrong/gone or there is a parameter telling lathe to disregard them is wrong

maybe

wb
 
Thanks very much for the replies. Confirms that I'm thinking along the right lines in diagnosing this.

Parameter is set to use timer for chuck close confirmation. As a test, I switched the bit in question (R49 bit 0 "chuck stroke confirmation use") and got a prox switch error so I'm pretty sure it is set correctly. The chuck close confirmation time parameter (T2) also has the default value of 100.

Tool eye on this machine is non-functional and disabled at R50 bit 0 (value set to 0, in Tool Data menu selecting MSR on/off has no effect). Even so I would like to verify the switches are working in case this interlock is still active. Haven't messed with them since machine was powered off.

Tailstock quill out of position- do you mean having the forward/retract switch for the quill set to "neutral"? I don't think there is a position sensor for it since the tailstock body needs to be manually unbolted to move it (therefore what would be the point of monitoring quill position).

Another thought, have not loaded chuck data back into the machine since downtime. Maybe this is making it unhappy?

Can anyone tell me how to access the ladder monitor on this control? I'm hoping I will be able to check all these inputs from there to verify chuck close confirmation is working and switches are showing plausible values.
 
On a Mazak, this alarm almost always occurs when the machine thinks the chuck is open when it is given a spindle start command. Does the alarm occur with the chuck in the open position? Tool eye and tailstock quill issues would throw a different alarm. If it does not occur with the chuck open, your chuck is set for internal chucking. I believe the ladder access is through the diagnose softkey.
 
On a Mazak, this alarm almost always occurs when the machine thinks the chuck is open when it is given a spindle start command. Does the alarm occur with the chuck in the open position? Tool eye and tailstock quill issues would throw a different alarm. If it does not occur with the chuck open, your chuck is set for internal chucking. I believe the ladder access is through the diagnose softkey.

Hello Gobo,
I've tried every combination of chuck closed/open (set with toggle on front panel) and ID/OD clamping mode (set with keyed switch on side panel) and the error still occurs.
As far as accessing the ladder monitor, the only menus available under the diagnose softkey are "COUNTER", "OPTION", "DIAGNOSE ALARM", "DIAGNOSE MEMORY", and "DIAGNOSE SERVO". Maybe there is some maintenance mode I need to activate?
Thanks!
 
Figured it out- the tailstock quill had to be in the fully retracted or extended position, and the tailstock switch kept at the retract/extend position. So even if it were fully retracted but the switch was in neutral, the spindle would not start. I was assuming that once you had the quill in position you would switch to neutral-obviously I'm still training my brain to think in Mazak logic. Still would like to access that ladder monitor for future diagnostics, though...thanks for the help everyone.
 








 
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