Lathe Manual spindle control

[westyone]

@clover - Dear Sir. I would like to ask for your expertise in electronics to help me with the following. I have a CNC/Manual lathe. This lathe can switch between CNC and Manual modes. It has a release mechanism (see pics) for the Z axis ball screw and a switch to disable the X axis driver.

As all manual lathes it has a hand switch on the carriage for spindle control.

I have attached a PDF of the current wiring between MASSO and the VFD. Works good (see "Lathe spindle Manual over ride PDF")

I would like to modify the wiring to allow the manual switch to control the VFD when in manual mode (see "Lathe spindle Manual over ride2 PDF")

I am uncertain that diodes will be necessary to stop feed back to MASSO when the manual switch is used. Perhaps MASSO will just ignore the input voltage.

Your input is most welcome.

Best Regards

BobJ

 

[masso-support]

the best/simple option would be to use a multi-contact switch and you can then connect/disconnect your VFD signals between MASSO and manual control.

 

[breezy]

@westyone

Attached is the simplest circuit to do what you want, it uses a 3PDT switch to disconnect/connect Speed, CW & CCW between MASSO and the Manual control on the lathe.

I'm not to sure what the purpose of the relay is in your second diagram. From the photo of your lathe control panel there is a pot, you need to pick up the variable terminal to feed the change over switch.

Regards,

Arie.

 

[westyone]

Wow! I thank you Arie for that detailed drawing. Very kind. Let's take the Potentiometer out of the circuit. My thinking was during production it would be advantageous to not have to deal with additional switches (3PDT) when I needed to run a tap, polish a diameter or chamfer an edge with a file.

The relay would switch on the "Speed pot power" to the 0-10v input whenever a manual spindle direction was commanded by the hand lever. Yes at full speed for that gear range but that's OK.

It's obvious one would't engage the manual control wile in cycle.

I am assuming the diodes would protect any electrical feedback to MASSO if that's even a concern considering they're optical isolated.

Best Regards

 

[breezy]

Quote from Westyone on August 31, 2019, 7:07 am

1. The relay would switch on the "Speed pot power" to the 0-10v input whenever a manual spindle direction was commanded by the hand lever. Yes at full speed for that gear range but that's OK.
   
2. I am assuming the diodes would protect any electrical feedback to MASSO if that's even a concern considering they're optical isolated.
   

1. Change the relay to 4PDT and connect it up as change over. That way you don't need any diodes.
   
2. The SPEED output from the MASSO is a analog signal and is not opto isolated.
   

Am I correct that the CW / CCW switch is a center OFF because if it's not then it will override the MASSO control signals.

Masso Support also suggested a switch to disconnect/connect the MASSO outputs. With the change over wiring you are isolating the MASSO and protecting the outputs.

Regards,

Arie.

 

[breezy]

@westyone

Had a further think about your circuit diagram, you are showing a connection from both CW & CCW plus a GRD to the relay. Are you connecting CW & CCW to the same terminal on the relay, if so that won't work without diodes, because you will be feeding the 15v+ from terminal 11 to both terminals 1 & 13A through that common point on the relay.

Regards,

Arie.

 

[westyone]

Quote from Breezy on August 31, 2019, 11:53 am

@westyone

Had a further think about your circuit diagram, you are showing a connection from both CW & CCW plus a GRD to the relay. Are you connecting CW & CCW to the same terminal on the relay, if so that won't work without diodes, because you will be feeding the 15v+ from terminal 11 to both terminals 1 & 13A through that common point on the relay.

Regards,

Arie.

Yes, I see. I like the 4PDT relay suggestion. I will substitute that for the 3PDT switch in your schematic. That will physically switch the VFD inputs from MASSO to manual automatically when the hand switch (center off) is thrown (I hope).

Many Thanks Sir