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Messages - OldePhart

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1
J11-13 are the home switches. J1-6 are indeed the stepper drivers (Clearpath SD) I removed both grounds and the problem stopped, but I did get spurious limit switch activation entries in the log with no pattern to them.
 
Later found that I didn't ground the VFD cable shield on either end (yes I am using VFD robotic cable...$$$) and had 50+ volts on it as well so that was likely a HUGE contributor to this as that cable runs parallel for a long time. That is now grounded on the VFD end, the spindle itself is grounded as well.

I haven't reconnected any of the board grounds to chassis ground and it seems to be OK... but... I built a touchplate and its on the J11 side, but when I touch the plate to the frame  I occasionally will set off the ++ limits even when nothing is moving and the spindle is off.

This gonna be one of those grounding nightmares . . .

2
Ok I'm finding that the IO is more resistant, but when the VFD starts, it stops right away. Certainly some effect from common grounding. removing the common grounding and the VFD starts up again just fine.  This is gonna be fun. . . .

3
Running a PMDX-126 and -107 on a 220v 3 wire power circuit. (2 phases and ground) .
I was getting spurious signal triggers and found that signal ground from J11,12,13 float. I think it says that in the docs so I wasn't surprised.
However I find that chassis ground to signal ground measures 50Vac and I'm sure that is the reason for the spurious signal triggers.
So I tied the signal ground to chassis ground and that fixed the issue... But I'm sure you left them floating for a reason,. Do you think this is a mistake and if so what other solution is there?

In addition what about the PC ground (J1-6) which are also floating at 50VAC ref to chassis. Should I ground it as well?

You carefully designed it to not be ground referenced so how badly am I messing this up by using a common ground for all?   

Its a new build, not retrofitting anything.

4
That would be a welcome addition - thanks in advance.

5
The Doc says that if I have a PMDX-126 (Rev C) , an ESS and a PMDX-107, I have to power the ESS from a separate 5v supply. Is that still true? I thought I heard Steve say that was no longer a problem, but I may have imagined it. 

If still true, which jumpers do I need to open? J3 and J4, but I thought there was a third one. I'm looking through the doc now but haven't located that info yet. 

6
Should have clarified that, motor is wired to PCGnd on the same connector as drive signals. That kind of screwup would have taken extra effort since the different grounds aren't even on the same side of the board, But I can't blame you for asking :) 

I see where you are going by moving the signals around and I will poke at that when I measure the current being drawn.  I see in the PMDX docs that expected the signal should be " At Least" 3.8 V so I think this is by design and might be incompatible without a kludge. If I have to build a follower circuit to bring the signal level up to proper spec, I will have to re think the PMDX.

I have a call into Teknic as well to see if I can expect to see signal inputs in their software as well as other ideas about this.

7
Brown, Yellow Org, Red to Gnd (Neg side of all)
Black (InputB) to J4-2 (Step)
White (InputA) to J4-3 (Dir)
Blue (Enable) to PC+5V - motor LED responds to this signal
Green (HLFB) floating - gotta work out the rest first

8
Hey 12, thanks for the reply.

I don't see the signals in the clearpath software, I see nothing there. But the drives work fine using the MSP software. 

What I see is that the LEDs on the PMDX board are blinking as I would expect, DIR coming on and off with each press of the test button and STEP barely illuminating and getting more intense as the pulse train ramps up.

I looked at these signals with a scope looking for pulse duration and better see what was actually happening and thats when I saw the low volt signal. I understand that excess current would drag the signal down, but as you said the board should be able to provide what the Clearpath requires and other folks have this working.

I don't have a current probe for this scope so I can only read the DIR signal's current with a meter, I can do that tomorrow. FWIW I did reverse them with the config dip switches and the results were the same. Its also of note that the PC +5v pin is fine the whole time.

The Clearpath motor is set for Step and Direction -doesn't appear to have any other options available, they are greyed out in the software. I never saw any way to tell it what signal types to look for but I was hoping there was such an option in there somewhere.

Set for 800 Pulses per rev, as delivered.

Config switches are set per switch table, the pulse train occurs when it should and direction toggles properly as well, its just that the voltage is too low.

I'm not following what you mean by using the PC+5V to the Clearpath + etc.

9
Might be on to something, 3.8V drive signals. I wonder if thats below the threshold of the Clearpath motors. the +5 rail (PC+5v) on the 126 is +5v but step and direction are low.

10
Thought I thanked you for this reply but I see no evidence of that, apologies.

11
I bought the pmdx-126 and a smoothstepper and am wiring it up today.  I have a single motor hooked up, enable works as indicated by the clearpath LED changing color, and I can see the step and direction LEDs lite up when I enter the boards test mode and hold the button down. But the clearpath doesn't move.  Moves fine under clearpath software (USB connection).  is there an incompatibility with the test signal and the clearpath? Other ideas?

12
posted in wrong forum

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I want to create a electrical drawing of my system, Are there line drawings of the -126, and -107 boards somewhere? Not a board schematic, though I wouldn't turn that down, more like a board drawing with the connectors labeled so I can draw lines from each component to the next.

14
Can the -107 be mounted with a ribbon cable instead of to the board? It has an uncomfortable twist in it when I use the screw and I would prefer to mount it on the same plane as the ESS and the -126 anyway.

15
Quote
I'm not sure what you mean here.
From the 424 page...
Quote
3) The motion control pulse engine generates pulses independent of the host computer timing and provides real time control for smooth step pulse signals . . .

Perhaps the SS does the same thing, but it's that sentence that has my attention. I'm using the ClearPath motor and they have their own intelligence built into them ensuring that if I send 100 steps, by God it's gonna do 100 steps if it has to tears its way off the gantry to get there,  (and holy crap are they strong!).

So in any case, even with normal steppers, if the 424 generates pulses independent of the host timing, wouldn't that be a bad thing?  I guess I need an example of when that is beneficial.

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