PMDX-110 Machine Shuts Down At Random

[fc60]

Greetings,

I have a Smithy CNC1240 with a PMDX-110 Breakout Board.

I am using LinuxCNC 2.5.4 with the Smithy INI and HAL files.

I keep getting a "joint 0 on limit switch error" that I cannot determine the cause of.

When I issue an M03 spindle command, the error occurs and the machine stops.

I disconnected the Spindle Control cable and was able to HOME the machine, JOG the machine, and run a program with no spindle commands.

Well, that did not last long as I was able to run a program to completion and when I started it again the machine shut down with the "joint 0 on limit switch error" in the middle of the program.

I was able to run the VFD spindle manually; but, now I get a "Low voltage error" to the VFD control. This is intermittent as it seems when the machine warms up the inability to start the spindle returns.

(Update: The low voltage error is due to the CNC control cutting off power to the VFD, so naturally I would record low voltage error. I have since "hot wired" the VFD direct to the wall socket and it runs fine.)

I have some test meters available to take voltage readings, etc. with guidance.

Hopefully, someone will be able to help me sort this out.

Cheers,

Dave

[Bob at PMDX]

Wow, its been quite a while since we've dealt with that board.  My first thought is that one of the power supplies is marginal.  Can you remove the connector on J1 and still run the machine?  This is located near the center top edge of the board, with a silkscreen label "Pot and Fwd/Rev Swt".  If not, will your voltage meter probes make contact if you slide them down into the connector along side the wires (that would work on either J1 or J2, which is right next to J1)?

If so, power on the board (and machine).  Put your meter on DC Volts and set the scale to the something close to, and above, 10 volts.  Put the negative meter lead on J1 (or J2) pin 6 (just above the silkscreen word "Pot"), and the positive meter lead on J1 (or J2) pin 4.  You should read something close to 10 volts (perhaps 10.1 or 10.2V).

Now try to turn on the spindle and see if the voltage reading changes.

Bob

[fc60]

Greetings Bob,

Thanks for the reply.

My machine is a Smithy CNC1240 with a VFD spindle control. The spindle signal cable is connected to J2.

I am using LinuxCNC 2.5.4

Initial power up gave me a "joint 0 on limit switch error". I cleared the error and was able to power the machine on and off several times.

With the machine powered up, HOMED, and idling. I get 10.41 VDC @ J1 pins 4&6.

Machines acts the same with the Spindle Signal cable connected or not.

Checking J2 pins 4&6 I record voltage according to the SxxxxM03 command I issue. (Checked with plug attached to BOB)

S1000 2.4VDC
S2000 4.90
S3000 7.40
S4500 9.84 (Max spindle speed according to factory manual)
S5000 9.85

By the way, no spindle movement as I disconnected the signal cable from the VFD

Cheers,

Dave

[Steve Stallings]

Dave,

Just trying to close out this issue.

The voltage reading that you reported seem acceptable.

Is your machine running properly now?

Steve Stallings

[fc60]

Greetings Steve,

Thanks for the reply.

I commented out the line that reads the signal from the sensors. I can now turn on the spindle both manually and via MDI and program.

net limit match8.0.out axis.0.neg-lim-sw-in

# net limit match8.0.out axis.0.neg-lim-sw-in

Sadly, I have no hard limits and have to rely on the soft-limits.

Cheers,

David

[Grayson]

Happy to see a posting concerning the PMDX-110. We have a Smithy PMDX-110 in our mill and will be posting about our need for assistance.
Grayson

[Steve Stallings]

We will be happy to help you with your board. Assistance on the machine
wiring will be supplied to the best of our ability, but we did not do the
integration and may not be able to answer all questions. Likewise we
are not familiar with the software configuration on the computer delivered
with these machines.

There is a short description document for the board functions and connector
pinout for this proprietary Smithy board here:

http://www.pmdx.com/Doc/PMDX-110_Manual_01.pdf

[Grayson]

Thanks Steve,

We found that document just yesterday and it was a eureka moment for us. This weekend we will absorb the information. It should go along way in improving our ability to ask more thoughtful questions.

Our task:
To get Mach3 up and running on the Smithy 1240. We are dumping the LinuxCNC program.

I am rather confused by the spindle motor setup. The PMDX-110 is running the X,Y and Z just fine. We have not tried the A with Mach yet. The spindle is running but not under control of the software other than about 3/4 of max speed.

After looking at the new information we will create a new post.

Cheers
Grayson

[Steve Stallings]

The PMDX-110 contains circuitry that is essentially the equivalent of a PMDX-106
and that manual will be helpful.

There is a Test function described in section 2.7 of the PMDX-106 manual. We
highly recommend using this to verify operation of the PMDX-110 and the VFD
before attempting to configure the software.