[LRF]

Recently added a PCNC440 to our machines with a Tormach PDB. As you may know the control button for this version of the PDB is a pneumatic push button valve. Not electrical as on the 1100. I would like to add a foot control which would make tool changes much easier by freeing both hands. Is there anyone out there that has done this and what can you share about your design? I am thinking a foot switch powering a solenoid valve that would open an air valve, that operates the PDB. In addition I am thinking of adding a safety lockout that would disable the foot switch if the motor is running. Anyone know of a control signal already in the 440 control box area that in either on/off only when the spindle motor is turned on?

[jwatte]

I think a solenoid pneumatic valve seems like the appropriate solution.
Have you figured out which specific configuration it uses?
Don't know about the accessible signals, sorry.

[Dozer56]

I made the PDB for my 440 and used a cheap pneumatic 2way foot pedal ($26) from ebay. I didn’t figure it would last but it was a cheap way to get going, I knew I would not like a button, and am glad I have the foot pedal every toolchange, makes it convenient to have both hands free. Surprising that more than a year later it still works great, I thought about doing a electric solenoid but this simple setup with some 6mm airline has worked well, I don’t have a safety though you could engage it while the spindle is running but never have, I keep the foot pedal halfway under the stand so I have to reach a little to engage the cylinder and it is out of the way from being accidentally stepped on.
When I was planning mine out I thought that maybe I could wire a safety in with the motor cover switch if using a solenoid to stop the spindle if engaged but it still would be fast enough if the spindle was already running just stop it from starting if engaged, but this seemed to work so well and simple and cheap, I forgot all about it .

Good luck if you decide to build yours.

[davidloomes]

Shouldn't be difficult at all. The correct designation for the solenoid valve you want is 5/2 (5 port, 2 way). There's already a 24V dc power supply inside the wiring cabinet that does nothing except operate the relay for the flood coolant. It'd be easily upp to the job of driving the solenoid valve, so 5/2-24V is what you're looking for.

As far as spindle running signals are concerned, the obvious place is output 2 on the Leadshine controller. The pins labelled 2+ and 2- are shorted to turn the spindle on, open circuit to turn it off - they're connected to the motor drive EN and COM pins respectively. The best bet would be to re-arrange this so the leadshine output activates a DPDT relay (again the 24V supply should be ideal) and use one pole's common and NO connections to drive the motor drive COM and EN. Then wire the 2nd relay pole's common and NC pins in series with the foot switch. Shold give you what you want.

While you're at it, consider adding a pair of wires from the leadshine's unused output pins 3- and 3+ to the motor drive's COM and unused F/R pins. That'll give you spindle reversing when you turn output 3 on.

[LRF]

Thank you to all who have responded.
My plan is already to use a Numatics version of the valve as Dave described I have 3 laying around here. I knew about the 24 volt power in the box I also have a couple of similar wall warts around here. I am waiting for comments from Tormach concerning the desire to add a safety to the foot control. One concept we have is to add a current sensor to the motor power wires and feed it to a small micro and let it control the valve. If there is current then disable the foot control valve.
Other ideas are certainly welcome.
I also find interesting Daves thought on reversing the motor. I think I will check that out. Thanks

[LRF]

.........consider adding a pair of wires from the leadshine's unused output pins 3- and 3+ to the motor drive's COM and unused F/R pins. That'll give you spindle reversing when you turn output 3 on.

Dave quick question, how do I turn on output 3? Not sure I understand this correctly so would appreciate some clarification.

[davidloomes]

Afraid I use Mach 3 with my 440, not PathPilot. If you're using Mach3 too, then it's easy for me to explain, if not, then I'm afraid you need to talk to someone who knows how to configure PathPilot. I believe though if you know how to edit the config to tell it that output 3 sets the spindle direction then the UI should pick that up and give you the option as it does on the other Tormach mills.

It certainly works though and the motor controller does a nice job of implementing acceleration/deceleration curves so you can go from full speed forward direct to full speed reverse. Here's the result.

https://youtu.be/NA2jO0-i7_c

[LRF]

We use Path Pilot.
I talked to Tormach. They suggested using pin 5, EN, as it's state changes from a floating voltage to ground when the spindle motor is running.

[davidloomes]

Yes, they're right. Pin 5 labelled 'EN' on the motor controller is driven by output 2+ on the leadshine. We're talking about opposite ends of the same piece of wire!
The leadshine outputs are pretty much like a switch. When the output is turned off, pins 2+ and 2- are effectively open circuit. When the output is turned on, current can flow in the 2+ pin and back out of 2-. Since 2+ is connected to 'EN' and 2- is connected to 'COM' on the motor controller, that does as Tormach describe.