PMDX-125 and Pin 15 Input in Normal Mode

[jcdammeyer]

WIN XP, Smooth Stepper connected to PMDX-125 via two ribbon cables.
I can assign any of the other inputs in MACH3 to Pin 10,11,12,13 but not Pin 15.  Is Pin 15 always set up to record pulses regardless of whether pulse stretching is enabled?  Is that why the Inputx pins don't light up when the Pin 15 input on J12 or J11 is connect to the J12, J11 GND?
I have no problem with pins 11,12,13 as limits or probe.  Only Pin 15 LED lights up for either J12,J11 but mapped to Input 1 does not light the indicator on the MACH diagnostic screen like the Pins 10..13.

[Bob at PMDX]

Gee, a PMDX-125 and not a PMDX-126.  Haven't thought about those is a while.  There were several revisions of the PMDX-125, written just above the serial number block (like "E6", "D5", etc.).  Please tell me the revision, along with your DIP switch settings.

Is that why the Inputx pins don't light up when the Pin 15 input on J12 or J11 is connect to the J12, J11 GND?

and

Only Pin 15 LED lights up for either J12,J11 but mapped to Input 1 does not light the indicator on the MACH diagnostic screen like the Pins 10..13.

Let me see if I have this straight (presuming that you have the ESS Port 1 connected to the PMDX-125 "Port 1" (J16), and ESS Port 2 to PMDX-125 "Port 2" (J17):

(1) When you assign, say, Port 1 Pin 11 (from PMDX-125 connector J12) to Mach3 input signal "INPUT1", and then connect the screw terminal for pin 11 on J12 to the adjacent GND pin, the LED on the PMDX-125 board for pin 11 turns on AND the indicator on the Mach3 diagnostics tab for "INPUT1" also lights up.  Is that correct?

(2) And if you instead assign Port 1 Pin 15 to Mach3 input signal "INPUT1", and then ground the pin 15 screw terminal the LED on the PMDX-125 board for pin 15 DOES turn on but the Mach3 indicator for "INPUT1" does NOT turn on.  Is that correct?

(3) And if you assign Port 2 Pin 15 (PMDX-125 connector J11, signal "D") to Mach3 input signal "INPUT1", and then ground the screw terminal the LED on the PMDX-125 board for pin "D" DOES turn on but the Mach3 indicator for "INPUT1" does NOT turn on. Is that correct?

In general, whether or not the pulse stretching is enabled, the input signal on the PMDX-125 pin 15 input should always get to the PC (and therefore to Mach3).  The only difference is that, *if* the signal on pin 15 is toggling, the PMDX-125 may make the low (or high) portion of the signal slightly longer.  And pulse stretching should have no effect on the PMDX-125's J11 "D" input signal (which appears as to Mach3 as Port 2 pin 15).

I am curious that (if I read your message correctly), both the J11 "D" signal and J12 "pin 15" inputs on the PMDX-125 fail to be read by the PC.  So let me know if my above interpretation is correct (all 3 items).  And if you haven't tried exactly that configuration, try it and let me know what you see.

Bob

[jcdammeyer]

Please tell me the revision, along with your DIP switch settings.

PMDX-125 E6 Serial # 27039, All dip switch off.

Let me see if I have this straight (presuming that you have the ESS Port 1 connected to the PMDX-125 "Port 1" (J16), and ESS Port 2 to PMDX-125 "Port 2" (J17):

USB Smooth Stepper Ver. 1.2  Connected as you described.

(1) When you assign, say, Port 1 Pin 11 (from PMDX-125 connector J12) to Mach3 input signal "INPUT1", and then connect the screw terminal for pin 11 on J12 to the adjacent GND pin, the LED on the PMDX-125 board for pin 11 turns on AND the indicator on the Mach3 diagnostics tab for "INPUT1" also lights up.  Is that correct?

Yes and no. When the PMDX-125 Indicator goes ON the assigned indicator on the diagnostics tab goes off.

(2) And if you instead assign Port 1 Pin 15 to Mach3 input signal "INPUT1", and then ground the pin 15 screw terminal the LED on the PMDX-125 board for pin 15 DOES turn on but the Mach3 indicator for "INPUT1" does NOT turn on.  Is that correct?

Yes and no.  LED on PMDX-125 for pin 15 turns on but not the MACH3 diagnostics INPUT1 has no response regardless of the input state of Pin 15.

(3) And if you assign Port 2 Pin 15 (PMDX-125 connector J11, signal "D") to Mach3 input signal "INPUT1", and then ground the screw terminal the LED on the PMDX-125 board for pin "D" DOES turn on but the Mach3 indicator for "INPUT1" does NOT turn on. Is that correct?

It's Pin 'H" not "D".  "D" is assigned to the equivalent of Pin 17 on my board.  And oddly enough now Pin "H" (Port 2 Pin 15) is now working like the rest of the input pins.

In general, whether or not the pulse stretching is enabled, the input signal on the PMDX-125 pin 15 input should always get to the PC (and therefore to Mach3). 

Good to know.  Thanks.

I am curious that (if I read your message correctly), both the J11 "D" signal and J12 "pin 15" inputs on the PMDX-125 fail to be read by the PC.  So let me know if my above interpretation is correct (all 3 items).  And if you haven't tried exactly that configuration, try it and let me know what you see.

The J11 pins appear to now be functional.  Although open circuit is LED OFF; connected to adjacent GND sets LED ON.  With LED OFF a mapped pin on the MACH3 diagnostic screen lights the indicator, LED ON extinguishes the indicator.  Not a problem since it can be set to be active low on the Inputs Tab mapping from program interface perspective.

But still no MACH3 indication from J12, Port 1 Pin 15.  Very odd.  It all started when I tried to use Port 1, Pin 15 as the Probe Pin.  That's when I discovered it wasn't working.  I don't know why I thought there was an issue with Port 2 other than perhaps the inverted logic confused me.

Is there other diagnostic I can perform?  Something in the smooth stepper interface?  I've looked through the MACH3 screens and I can't see anything that might also be attached to Pin 15 preventing it's use as an input on the diagnostics.  Odds are I've done something stupid.  But what?
Everything else works.  Step/Dir along with Spindle On/Off control.  I've even used the A axis with a rapid prototyping extruder feed in place of the router.

I design embedded systems for my day job (http://www.autoartisans.com/ELS/) so I have the tools to dig in deeper.

Thanks.

Bob

[Bob at PMDX]

Yeah, you are right about the J11 pin name being "H", not "D".  I had forgotten about the port 2 output signals.

The inversion between the LEDs on the PMDX-125 inputs and the Mach3 indicators is expected.  The PDMX-125 LEDs (as you've noticed) turn on when the input is grounded, which makes the LEDs an "active low" indicator.  So, yes, to make the Mach3 indicators match you need to define the input signals as active low.

HOWEVER - that does not necessarily mean that your limit switches will be active low.  That depends on how you wire them.  If they are normally open switches then, yes, they will be active low.  If they are normally closed switches, then the Mach3 signal should be defined as active high (and the PMDX-125 LEDs will indicate "not at limit").

OK, back to diagnosing your problem.  It has been quite a while since I've run the ESS plug-in on Mach3, and I don't remember if the ESS plug-in has any kind of diagnostic screen that shows you what *IT* thinks are the states of the input and output signals.  Barring that, it looks like we are at the "take a voltmeter and measure" stage.  With the ESS connected to the ribbon headers on the PMDX-125, you can use the DB25 connector to look at the voltage on pin 15 (that will be port 1 pin 15 to the ESS and Mach3).  You can clip (or otherwise attach) the ground probe from your meter to any of the "PCGnd" terminals on connectors J1 through J6 on the PMDX-125.  Then take the positive probe and somehow connect it to pin 15 on the DB25 connector.  A paper clip comes in handy here.  When looking at the edge of the PMDX-125 board with the components on top, the DB25 pins are numbered 1 to 13 across the top from left to right, then 14 to 26 on the bottom row also left to right.  So pin 15 will be the 2nd pin from the left on the bottom row.

** EDIT **
NO!!!  They are numbered RIGHT to LEFT!!!  So pin 15 is the second from the RIGHT on the bottom row.  Sorry about  that.
** END EDIT **

  Measure the voltage there with the "Pin 15" screw terminal unconnected (and PMDX-125 LED off), and then with the terminal grounded( LED on).  If all is well you should see something close to +5V and 0V (likely around 0.2V).   If you are seeing those voltages at the DB25 connector and Mach3 shows no response then then issue is upstream from the PMDX-125.

Hmmmm....  a neuron just fired in the rusty part of my brain.  You said that the port 2 pin 15 wasn't working and then started working again.  This sounds like a possible ribbon cable issue.  Pin 15 is near one edge of the cable and sometimes, when a ribbon cable has been yanked on a few times (not that I've ever done that) the connections can loosen.  So try wiggling the ribbon cables near both ends to see if that makes the signals work, even intermittently.  You can also try swapping the cabled from port 1 and port 2.  Even better, if you have another, hopefully known good ribbon cable laying around somewhere that you can try.

Bob

[jcdammeyer]

Hi Bob,
Thanks for your support in this.  I was hoping to avoid taking the system apart to do that level of diagnostics thinking I'd probably just missed some hidden Smooth Stepper or MACH3 setup feature.  There is so much and it's easy to screw up.  Swapping ribbon cables made no difference.

So alas, sometimes the voltmeter and clip leads need to come out and simple testing is needed.  The PMDX-125 is good right out to the parallel port.    I also verified that the two J16,J17 ribbon headers produced signals on their pin 15s.

Next I thought I'd double check to make sure the connection from the ribbon cable to the back of the SS was intact.  The attached photo shows what I found.  Why there is a solid blob between pin 14 and pin 15 I do not know.  I don't remember ever doing that.  Probably been that way right from the start.  It's a very solid connection and not typical for the type of short you'd see if the wave soldering wasn't up to par.  So maybe I did. 

[Bob at PMDX]

Good detective work! And where ever it came from, at least you know how to fix it.