Mitsubishi MR-J2 BLDC AC Sevo With 7i33

Hi Every one, I have a situation I have a Hurco machine with DC Drive. Its Z Axis drive was faulty. So I replaced it with a mitsubishi MR-J2 series 2KW Drive and motor. before buying it I checked that it could take in analogue speed command. and it does but the problem is that it does not hold its position even when it is connected to ground. and there is no deadband voltage setting ( Below which drive considers it zero volt) I have tried offset in drive parameters but the motor does not hold still at any value . To hold / lock the drive it is needed to ground a pin through Optocoupler. Is it possible for linuxcnc to enable and output when zero speed command is given out. Or and other solution I am using 7i33 for analogue


Thanks

A analog input servo system will likely always drift slightly
when the drive is enabled but the PID loop is not closed.
This is normal and expected behaviour.

It is better not to fix this with a deadband or other tricks as this will worsen the servo response.

The fix is simply to not enable the drive when LinuxCNC is not in the machine-on state.
This is also a safety issue since LinuxCNC should be able to disable the drives if it senses a following error.

Drive enable is typically done by by using the HAL signal axis.N.amp-enable-out to enable the 7I33 analog out and perhaps a separate drive enable signal, for example. if you have a 7I37 output free you can use this as a drive enable signal.

The 7I33 has drive enable outputs but these are 5V logic level signals so would need to be translated to the signal level the drive/relay requires.

Drives that need a ON device to disable often need a relay in the enable logic since they must be on when there is no control power (normally-on OPTOs ( form B ) are available but rare )

I have connected servo enable. but the same same result I have tunned dc drives before but and one yaskawa sgdm drive I had a similar problem but there was deadband setting in drive and i gave it 0.005 volt and drive worked well. in mitsubishi there is no such setting. I have connected as you have suggested the drives is enable when F2 key is pressed. the motor starts drifting at a high speed when the P value is 1 which is default I lowered the value to 0.001and it rotated at a low speed as when no command is given ( at 0V. one thing I would like to mention I connected the command wire of drive to its ground but same result ). when i give P0.001 and d 0.05 the motor shakes if I reduce the value of d the motor drifts if I increase the value of p the motor rotaes at higher speed and trick for pid tunning of ac servo