Messages

1

Boards for use with LinuxCNC or MachineKit / Re: PMDX-126 with LinuxCNC and charge pump

« on: June 22, 2018, 11:03:53 PM »

My solution, at least temporarily was to switch over to MACH3 which can deal with that problem (feature).   It's been a month since I dealt with that.  In that month I've been rebuilding the power supply and control cabinet and all sorts of other things so at the moment nothing is wired up.  I had to abandon the BeagleBone Black using the BBB-DB25/26 from Xylotex running MachineKit because their hardware couldn't deal with NC limit switches.  Not without modifying the board.   And I'm not prepared to manually turn pulleys to back off the limit switches as was suggested.  So for now I'm back to a dual core PC that runs either MACH3 or LinuxCNC.   Once I have the machine put back together and wired and making chips with MACH3 I'll take another look at LinuxCNC.

Thanks for your reply.
John

2

Boards for use with LinuxCNC or MachineKit / PMDX-126 with LinuxCNC and charge pump

« on: May 23, 2018, 12:20:00 AM »

I've been struggling to get the PMDX-126 to work with a LinuxCNC controlled parallel port.  The StepConf Wizard for LinuxCNC does not create the correct .hal file to re-enable the board after an ESTOP.  With dip switch 1 set to enable the Charge Pump the PMDX-126 correctly leaves the outputs off until the PC generates the 5Khz charge pump signal.

Where I ran into problems is when the ESTOP switch is opened.  The red LED comes on and outputs are disabled.  But at that point closing the ESTOP again doesn't enable the outputs.  A scope shows the charge pump square wave is still there on PIN 17 but PIN 10 remains high.

The PMDX-126_19 manual states in a 'note' on page 28 that the charge pump signal will not affect the ESTOP status.  I've found that not to be true.  Until the PIN 17 charge pump signal goes away, the PIN 10 ESTOP stays high no matter what is done with the actual switch.
The .hal file needs to be modified to make this work. 

# first remove the charge-pump enable which was controlled with the screen base ESTOP button.
#net estop-out charge-pump.enable iocontrol.0.user-enable-out
net estop-out iocontrol.0.user-enable-out

net estop-ext       <= parport.0.pin-10-in-not

Near the end of the .hal file connect the external estop input (PIN 10) to the charge-pump.enable.
net estop-out <= iocontrol.0.user-enable-out
net estop-ext => iocontrol.0.emc-enable-in
net estop-ext => charge-pump.enable

Now what happens is that when the external ESTOP button is pressed the open circuit results in a high level on PIN 10 which is inverted by the 10-in-not part of the net estop-ext statement.  This now logic low is connected to the charge-pump.enable disabling the 5kHz charge pump signal.  The MACHINE ON button is also disabled clearing any spindle and coolant ON settings

At this point although the ESTOP switch is still open circuit, once it's closed again the PMDX-126 will re-enable. Now it correctly sets PIN-10 low which then (inverted to 1) allows the MACHINE ON button in the LinuxCNC to be enabled along with the Charge Pump signal.

John



 

3

Parallel Port breakout boards, motherboards, and dedicated accessories / Re: PMDX-125 and Pin 15 Input in Normal Mode

« on: July 06, 2015, 03:48:55 PM »

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. 

4

Parallel Port breakout boards, motherboards, and dedicated accessories / Re: PMDX-125 and Pin 15 Input in Normal Mode

« on: July 06, 2015, 03:16:19 AM »

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

5

Parallel Port breakout boards, motherboards, and dedicated accessories / PMDX-125 and Pin 15 Input in Normal Mode

« on: July 04, 2015, 04:34:25 AM »

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.