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Threading - no rpm in display

Jan
 

Gentlemen, I kindly ask for your support

My cnc 5 hangs, when the program reaches G78. In manual mode it shows rpm. When I switch from manual to cnc mode the indicator turns dark. Obviously it's because it cannot read the rpm. When I switch back to manual mode it starts cutting the thread, then alarm 6 is displayed.
Any suggestions or tips how I can solve this problem?

Thank you guys!

Jan

Dieter
 

Hello Jan,

Alarm 6 says "Spindle speed too high", it's described in the CNC 5 Manual.
Reduce the rpm and stay in CNC-mode and the threading works.

For the display in CNC-mode I had the same problem, but it's not a fault,
My machine was also configured without display in CNC-mode.

First you must have the DNC-board with the motor relay (you can see it below the connector on my picture)
and the CNC-HAND switch on the front-panel.
One must shift the plug for connector X61 on the DNC-board one position so that the plug is flush with pin 1.
I added a picture from my machine.

Be ware of mains potential on this connector, first unplug the mains.
No warranty if it works for you because there are differences from machine to machine.
Hope you don't blow up the electronics, do it at your own risks.

Dieter

Jan
 

Thanks a lot, Dieter! I'll try with some adjustments to go with lower rpm.
The lathe was modified by the pre-owner, it has a servo-motor controlled by a frequency converter, but I can use the original pot for adjusting the spindle speed. Good thing, but probably this caused the loss of the indicator in cnc-mode. And maybe a bit too much power for this little lathe (2.2 kW...)
If it works with less speed I'll leave the electronics at the moment, just for safety reasons. But great info, thank you!

Jan

Dieter
 

Hi Jan,

Stay with the the servo-motor, it's a good solution.

If the relay on the DNC-board still switches the motor you can try shifting the plug,
supposing the original motor controller with his LED-display is still in place. The display electronic works independently from the motor electronic
without any connection.(the great gap on the controller board shows it)
The relay on DNC not only switches the motor (with 2 contacts parallel) but the third contact switches the 10 V for the display (parallel with the Hand / CNC switch.
The switch-output for the motor is doubled on X61 on pin 1/2 in and 8/9, this enables by shifting the plug by one position to have display in CNC-mode or not.
Because mains and 10 V are on the same connector be ware when working on and check triple with the picture of plug X61.

Dieter