PMDX-126 and ESS Relay Mist Problems

[Techsavvy34]

I'm having a weird a problem where my fogbuster won't turn on.  The first time I power on the pmdx-126 and run gcode through mach3 the relay will turn on when prompted by the M7 gcode but after two tool changes the relay won't turn on the fogbuster when a M7 command is issued.  If I try to turn it on manually on the mach3 screen it show's that output 1 is enabled but the fogbuster still doesn't turn on.  I'm using the K2 relay on port 1 pin 14.  Does anyone have any suggestions?  I also have a pmdx-107 installed I disabled the spindle relays because I'm controlling the spindle manually at the moment.  Should I switch the K2 relay to multimode and use port 2 pin 14?  I was looking over the manual and noticed that the relay's have status leds,  I'll see if the led is lit when I enable the fogbuster.  I just think it's strange how it will work for two on and off cycles then it quits working and even If I reset the board and mach3 it still doesn't work again.

[Bob at PMDX]

First - yes, check the LED for the K2 relay to see if that indicates that the PMDX-126 board is seeing port 1 pin 14 behaving as you expect.

The first thing that comes to mind is that you *might* have two signals trying to drive port 1 pin 14.  The standard Mach3 configuration when using the PMDX-107 is to have port 1 pin 14 assigned to the spindle direction signal, and port 1 pin 16 assigned to the spindle "step" signal (actually the PWM signal).  This is the configuration described in our app note "AN002 - PWM Spindle Speed with Mach3, Smoothstepper, PMDX-126 and PMDX-107" (http://www.pmdx.com/AppNotes).  And then you also have the "Mist" output trying to drive port 1 pin 14.

You have two options:
(1) As you suggested, you can change the JP2 jumper AND DIP Switch "Config8" so that port 2 pin 14 drives the K2 relay (see table 4 on page 11 of the PMDX-126 User's Manual).  Presuming of course that you have the 2nd parallel port connected to the PMDX-126.

(2) If you are not using the spindle direction signal (i.e. your spindle only runs in one direction), you can change the spindle direction signal to pin 0 (zero), or some unused pin on port 2 or port 3.  WARNING: I haven't tried setting a signal to "pin 0" to disable it when using a SmoothStepper.  I know this works with the normal parallel port interface in Mach3 (the parallel port driver simply ignores any invalid pin number).

Bob

[Techsavvy34]

I switched the k2 relay to port 2 pin 14.  The fogbuster worked two times but wouldn't turn on the third time.  I checked the relay led and it was on.  So it is receiving the signal from mach3 but it isn't turning on the relay for some reason.  The fogbuster works fine if I plug it into a 120v outlet.  I just noticed that I forgot to hook up the solenoid to the MOV terminal.  Would this cause problems?  I think I'll switch it to relay K1 and give it a try.

[Steve Stallings]

Using the MOV is desirable when driving a solenoid, but I doubt this is your problem. When a relay gets damaged by back EMF when a solenoid turns off, it usually welds in the on position. Also, I doubt that your solenoid is enough of a load to cause damage in the first place.

Can you try a small lamp or other device instead of the fogbuster to confirm that the relay contacts are not in fact closing?

Another last minute thought. Are you using an ESS and trying to power it from the PMDX-126? The PMDX-126 power system was adequate for power a USB SmoothStepper, but not the ESS. Erratic operation of the relays would be a likely symptom of this problem.

[Techsavvy34]

Yes I'm using the ESS and powering it from the PMDX-126.  I just recently started having another problem where it seem's that the ESS loses all power and mach3 freezes.  When this happens and I look at the boards all the leds on the ESS are off and on the pmdx-126 the estop led is dimly lit.  Do you think the estop led is lit because when the ess loses power Mach3 no longer sees the charge pump?  I'll try running the ess with it's own power supply and see what happens.

[Bob at PMDX]

As noted in the PMDX-126 User's Manual (granted, not painfully obviously):

WARNING:   If you are using an Ethernet SmoothStepper (ESS), be aware that the PMDX-126 can supply enough power only if the ESS is the only device drawing power from the PMDX-126.  If you plan to use a PMDX-107, PMDX-108-Input or PMDX-108-Output (powered from thePMDX-126), PMDX-104 or PMDX-105, or any other device that draws power from J1, J2, J3, J4, J5, J6 or J7 then the ESS MUST be powered from an external power supply.

Since you have a PMDX-107, you *MUST* power the ESS from an external supply.  Hopefully that will fix this problem.

Bob

[Techsavvy34]

Thanks for your help Bob and Steve.  I'm now powering my ESS with it's own power supply and it's working great.  I no longer have problems with the coolant relay and the ESS has stopped randomly shutting off.
Now I just have to get my spindle and new vfd wired up and I'll be all set.  Again thanks so much for your guys help.  Your customer service is amazing that's why I never have a problem buying one of your products.