Messages

1

Parallel Port breakout boards, motherboards, and dedicated accessories / Re: PMDX-126 & UC400ETH Compatibility

« on: December 31, 2016, 12:00:12 AM »

Update:

The PMDX-108 board is not - NOT - compatible with the UC400ETH or UCCNC.

My earlier reports were premature, as I saw the lights blinking properly on the 108 and figured all was well. After getting the UCCNC license I discovered a minor detail...

Turns out that the 400ETH cannot swap outputs for inputs on Port 2 as is required by the PMDX-108.  While I read the 108 instruction manual, at the time I glossed over the explicit statement about 'requires software that allows the data bits of the parallel ports to be used as inputs."

This is the price of not knowing jack about electronics and stumbling my way through a mill overhaul.

There is absolutely nothing wrong with the 108, and I suspect it would work fine if the UC300ETH were used as it has many more inputs on the #1 & #4 ports.

Luckily my spindle encoder could be connected directly to the PMDX-126 Port 1 Pins 11, 12, and 13 and is working beautifully.  I have the UCCNC software reporting actual spindle speed within 5 or 10 RPM of a photo tach all the way from 100 to 8k rpm.  Just needed some serious PWM & other fiddling.

Rigid tapping (in air) is next.

-Spumco

2

Parallel Port breakout boards, motherboards, and dedicated accessories / Re: PMDX-126 & UC400ETH Compatibility

« on: December 22, 2016, 10:11:52 PM »

tygerwolf76,

I'm in the process of overhauling my mill using the same components.  I'm using a PMDX-126, PMDX-107, PMDX-108 (input), and a UC400ETH.  Currently running Mach3 with the UC plug-in, but I'll be getting the UCCNC license shortly.

I'm not done with everything, but I now have the axes moving under PC control, and the spindle is turning.

The PMDX components are top notch.  No hardware problems at all, and the UC400ETH is communicating properly with the PMDX stuff - including the 108 input board.  I am having problems with the UC Mach3 plug-in, but the UCCNC folks are working on it and will hopefully get it sorted after the holidays.

Problem 1 is that M03 and M04 commands do not change the DIR pin state.  Both commands rotate the spindle the same direction.  It's not the UC400ETH, PMDX gear, or the VFD; it's a software problem.  UCCNC support gave me a workaround (that works!) until they can troubleshoot the plugin.

Problem 2 is that the spindle pulley ratio feature is not working, and I suspect this is also the UC plugin acting up.  Doesn't matter what ratio I set the pulley to in Mach3, the "S" command results in the motor rotating at the command speed (not the spindle).

Using a higher-end Monarch strobe, I was able to tune the PMDX-107 to within 0.5 RPM of the target speed on my motor/VFD combo under 'Test' mode.  Dropping the RPM in 'Test' mode to 30% mode was within 1.0 RPM.  There was essentially zero RPM fluctuation, and I'm pretty satisfied with that.  It should get even better when I get around to installing my spindle encoder.

You might consider going with the UC300ETH and motherboard instead of the 400.  CNC4PC is still offering a free UCCNC license with the 300, which means it's actually cheaper than a 400 + license.  I was a little annoyed as this deal was offered about 2 weeks after I bought the 400, but such is life.

3

Cables, connectors, switches, contactors, sensors and other items / Re: Inductive sensor shielding

« on: November 08, 2016, 12:42:54 PM »

Awesome - thanks again for the guidance.

4

Cables, connectors, switches, contactors, sensors and other items / Re: Inductive sensor shielding

« on: November 08, 2016, 10:57:21 AM »

Steve,

Thanks a ton.  Is there something I need to do to connect J11 or J12 to the control cabinet, or are they grounded through the board mounts?

5

Cables, connectors, switches, contactors, sensors and other items / Inductive sensor shielding

« on: November 08, 2016, 08:57:16 AM »

Dear PMDX,

I have inductive proximity sensors I'm connecting to a PMDX-126.  The cables are too short and I've purchased some 3-conductor foil-shielded cable to extend the run to the 126.

Question - the original cables are not shielded.  How would you suggest terminating the shielding (there's a drain wire available) on the cable extensions?  The easiest way appears to be installing a screw terminal on the enclosure backplane adjacent to the 126 board and connecting the drain wire from the various sensors to this (new) earth terminal.

Or - leave it floating and don't worry about the shielding?

Or - connect all the drain wires to a conductor and terminate the conductor at some other ground point?  Such as the star ground block inside the enclosure (adds about 10"-12" from the proposed backplane terminal location).

Or - is there some location on the 126 that is suitable for connecting the shield drain?  I suspect not, but figured I'd ask.

Thanks,
Spumco
Thanks

6

Parallel Port breakout boards, motherboards, and dedicated accessories / Re: PMDX 126 & 108 - Spindle Encoder

« on: October 08, 2016, 10:20:09 PM »

Awesome.  Thanks so much for the help.

I'm sure I'll be back to pester you all when the 126 & 108 show up.

Regards,
Spumco

7

Parallel Port breakout boards, motherboards, and dedicated accessories / Re: PMDX 126 & 108 - Spindle Encoder

« on: October 07, 2016, 11:57:59 PM »

Bugger.

I dont need resolution that fine, but the encoder came with the motor and I was hoping to use it.  Oh well, it's just money.

Any suggestions for an appropriate ppr to work with the VFD and the 108 board?

8

Parallel Port breakout boards, motherboards, and dedicated accessories / Re: PMDX 126 & 108 - Spindle Encoder

« on: October 07, 2016, 10:39:01 AM »

Bob,

Thanks much - quite a bit more clear.  I'm still confused, but less so.

The quick ref guide doesn't identify it, but the main VFD user manual indicates "EA" takes a 5-24Vdc signal on page 3-114 in the table.  "EB" is 18-24Vdc only.

I have a 2048ppr encoder, so I'll have to figure out something.  I plan to spin to motor up to 5kRPM, so that's something like 170KHz - too much for even the "EA" terminal.

I found that Mesa Electronics has two very inexpensive items related to this particular problem.  They have a 'ENCY' board that is a differential signal splitter.  One in, two out - that should allow me to get noise-resistant differential signals very close to both the VFD and the 108 board before converting to single-ended signal.

Second, they sell a '422ENC' board that appears to convert differential RS-422 signals to TTL.  One of the ENCY and two 422ENC boards appear to be the ticket.  I'm awaiting a response from them as I'm not sure the 422 board can handle 24Vdc inputs.

I did not realize that I could send the A+B+Z+ signal one place, and the A-B-Z- to another component.  Interesting, as the UCCNC software permits me to 'flop' the encoder inputs to ensure that spindle direction is accurate.

So... sounds like the 126 & 108 combo are on the menu, and the 105 is out. The home/limit switch convenience is worth it alone.  Order placed.

Now, if you're still willing to help with a non-PMDX issue: how do I reconcile the encoder PPR to VFD frequency limitation problem?  I know I can set the PPR in the VFD, but I assume the VFD can't even read the signals fast enough to do the PPR math (given the 36KHz or 2KHz limits).

Is there some 'counter' board in the universe that will drop the encoder pulses down to a frequency the VFD can accept?  Or... if I just hook the index (Z) signal to the "EA" input and have a 1 PPR encoder pulse would that still work?  The PMDX/ETH400/UCCNC would get the full 2048 PPR signal, but the VFD would not...

As far as using the "EA" terminal only (single phase), I'm confused by the VFD manual.  Page 3-115 illustrates three diagrams for using the "EB" terminal as a direction indicator, but I'm lost.  The first one appears to be a relay-sourced voltage input (assuming 24Vdc) where voltage in indicates FWD and 0Vdc indicates REV.  I might be able to do this using the 106/107 FWD/REV relay?

Thanks again,
Spumco

9

Parallel Port breakout boards, motherboards, and dedicated accessories / PMDX 126 & 108 - Spindle Encoder

« on: October 06, 2016, 11:18:52 AM »

Having a problem as I go through the process of designing the control system on a 4-axis mill (retrofit).  As I'm sure you're used to hearing - I'm a novice at this stuff so electronic terms may go sailing over my head.

Current hiccup is that I'm trying to get the spindle encoder signal to both my VFD and the control software.  The VFD needs feedback for low-speed accuracy and improved torque, and the software needs it to do rigid tapping (via electronic gearing between spindle and Z-axis motor).  I'd like - but don't need - to send an index signal to the software as well in case I fit a tool changer that has to be homed.

The WJ200 VFD accepts a 2-channel single-ended signal (A, B, GND).  The A-terminal can be 5-24Vdc, but the B-terminal must be 24Vdc only.

The software and motion controller (UCCNC/UC400ETH) can monitor 2 pins for a spindle encoder signal (A, B), as well as an index signal.

My spindle motor encoder is a BEI quadrature with index (A+, A_, B+, B_, Z+, Z_) and operates at 5-24Vdc.

Other inputs (not including estop, resets, enables, etc):
3/ea NPN-NC homing (10-30Vdc)
1/ea NPN-NC limits (6/ea 10-30Vdc, series)
1/ea 24Vdc VFD alarm signal
2/ea touch probes (future)

Although I already have a two-port BOB, it is restricted to 5Vdc only inputs.  This is going to be enough of a hassle to attach the 24Vdc inputs that I'm happy to spend money on a PMDX BOB that makes wiring/integrating easier.

It appears that a PMDX 126 plus a 108 input board will provide me with the inputs I need/want for current and future expansion, as well as making the wiring easier for homing/limits.  If not, please let me know. 

Spindle control will be via a 106 board I bought from you a couple months ago based on a plan to try to integrate the OEM control hardware with the VFD.  That plan has been abandoned, but the 106 appears to be the ticket for spindle 0-10Vdc control and I have it in hand.  I don't see a need to buy a 107 (or something else) if the 106 will do.

My questions
1. How do I split the quadrature signal from the encoder to both the VFD and the 126/108, and is there some reason I shouldn't do this?  I don't think any small timing difference between the two signals will cause issues as the VFD and UCCNC shouldn't be competing.

2. Can the 105 translator board take the quadrature signal and change it to single-ended?  It appears that this is the case, but I'm trying to double-check to compensate for my total lack of experience with this stuff.

3. Assuming that splitting the signal isn't a bad idea, should I split the quadrature signal, or split the single-ended signal?  i.e. two 105 boards and some sort of splitter upstream, or one 105 and a single-ended signal splitter? My guess is that the less single-ended wiring I have, the less chance of noise interference and placing the 105(s) as close to the VFD and 108 is preferred.

[The VFD and low-voltage hardware are in different enclosures, so there will be 24"-36" of cable from the encoder termination (105 or splitter) in the low-voltage enclosure to the VFD.]

4. I'd like to keep as much in the control system at 24Vdc as possible.  Can the 108 take a 24Vdc input (presumably from the 105) rather than me trying to figure out how to drop it to 5Vdc? Or does the 105 drop the outputs down to 5Vdc? In which case, how do I maintain the 24Vdc signal to the VFD?

Enough for now.  Thank you in advance for any assistance you can give me with this.

Regards,
Spumco