Help! 1 of 5 steppers working..

Hi everyone!

It's been a really long time, I just haven't had time to play with this CNC project for something close to a year due to family/renovation/interstate employment dramas....  Honestly, I'm basically relearning this stuff since my memory isn't as great as I'd like it to be. So please forgive my re-newbie status.

After much ado... I've started to build the actual machine, but before I got too far, I wanted to check if my previous work (control box, system config) was still ok....

I dusted off my control box and LinuxCNC computer, motors and cables... only to find things have indeed gone awry in my neglect.

The PC stopped booting... so I resurrected the hard disk, backed up the config files, replaced the hard disk with something a little less... beaten up.. then reinstalled. Ok, I'm an IT nutter, and installing an OS... that's my wheel house.. no dramas there. Still got some minor OS config issues to work out, but for the most part, it looks good. Talks to the Mesa card over ethernet, on 10.10.10.10 address, and clearly works with WiFi, since I'm using the system to create this post.

I got a little... not arrogant.. but perhaps a little less humble, when I thought... "Hey maybe this won't be so hard!" (in my naivety)

So getting encouraged, I fired up the control box... everything turns on as expected... all 5 CL86Y stepper drives in non-alarmed state, Mesa 7i76e card lit up. VFD responds to 10V analogue input. Great... although it's spinning backwards (I'd disconnected the spindle a year ago.. so I guess I wired it up incorrectly. So I swapped any two of the power wires around on the VFD  to shift the direction... (a little trick I learned building a spindle-driven router table in prep for this project) and everything is golden.

Did some basic jogging using the Gmocapy interface... I started with my 4th axis because that's what I landed on... it works beautifully. I tried some basic MDI commands... and noticed no other steppers respond...

So! 4 out of my 5 stepper motors (interestingly, all failing motors are connected to TB2 on my 7i76e) and they are completely unresponsive to Step/Dir signals. The fifth stepgen on TB3 works perfectly. No alarms, no errors.. as far as LinuxCNC is concerned, the motors are responding as they should... but they're not in my little garage-shaped reality.

Interestingly, all 5 motors are powered... leave the system alone long enough, they get warm... and I can't turn them by hand. If I force them with clamping pliers and an old towel/rag, they fight me, then alarm when I go to far.

So... Stepper Driver-Motor cables look good... at least in theory. Perhaps it's a Mesa-to-Driver issue?

So I checked each and every Step/Dir wire from the Mesa 7i76e stepgens to the driver... and they're ok. I've just finished checking encoder cable from the driver all the way to the socket that the motor plugs into, the encoders check out, (makes sense since drivers are all happy with "no alarms here"). I

So my current thoughts are:

1. Somehow all TB2 connections aren't working.
2. Is there some jumper, weird PNCConf setting I'm missing? When I use PNCConf... The I/O connector 1 (presumably TB2) Are configured as:

        0: X Axis StepGen
        1: X2 Tandem StepGen
        2: Y Axis StepGen
        3: Z Axis StepGen
        4: A Axis StepGen

Any guidance would be great. I've included my "SpindleGood" config files, so please let me know if I've missed anything you might need.

I truly hope you're all well, whether you can help me or not. I've just been beating my head up against this for a couple of days, and I'm really starting to run out of ideas.

Thanks for reading!
Hamish.

P.S. Any Forum users in Canberra? Love to see a working system, and chat about it!

 

Hi Tommylight,

I hope you and your white "fluff ball" is well. I dimly recall you mentioning that you had one a while back.

Thanks for the response. I'll look into those suggestions tomorrow. I was also going to use the driver configuration adaptor+ software to see what the little in-built signal oscilloscope is reading.

-Another thought... maybe the FPGA's memory has been corrupted. I was thinking about reflashing it from the backup.. just to see if that does anything.

Will have a look, try each suggestion, and see what's going on. Will relay what I find here in a day or two.

If no axis on TB2 work and you had a previously working hal/ini file setup,
that may mean than one of both of the step/dir driver chips for stepgens 0..3
have been damaged (these are U12 and U19)

This can happen is step/dir signals get accidentally connected to something
outside of the 0 to 5V range, say field power.

You can check for damage by measuring the output voltage on the step/dir pins (from + to -)
These should all read 5V when LinuxCNC is not running.

Hi PCW,

You must know the card well. I presume you work for Mesa, or have some serious electronics skills. Either case, I appreciate the information. So here's what I found....

I just checked, and the stepgen on TB3 it checks out to 5.04V, whereas the rest on TB2 range show voltages around the 0.45V mark (so less than 10% of intended). I was kinda hoping it'd be a jumper setting, but guess it's a chip issue as you say.

Honestly, I don't know how this could have happened in my absence. It was literally running until 1 minute before I packed it up, (Job offers saying "You start 7am tomorrow" do that) so the box was locked and disconnected from power. (I repurposed my 15A cables for my welder and other equipment that I took with me.. so if it got voltages higher than 5V.. I'm not sure where it came from). In any case, "Strange things are afoot..."

I looked at both U12 and U19 under a magnifying lamp... no sign of heat damage or cracked/cold solder joints.. not that it necessarily means much. I also checked the solder joints for TB2.. no obvious problems there either.

So... I presume I need a new 7i76? Given the short supply on Mesa's online store... I maybe outta luck here. Any chance of repairs? I'm not geared up for surface mount soldering though... my hands aren't THAT steady, nor is my sight THAT great.

Hmm, I think I'll email Mesa for advice.

Thanks for your help!
Hamish.

The card is repairable, request a RMA# from Mesa

Hi all,

I hope you're all having fun, wherever you are.

Thanks to all who've responded to my pitiful pleas for help. I've contacted Mesa re: damaged 7i76e board, but have yet to receive a response. Admittedly, it's been one business day, but I was hoping I'd know how to proceed from here. I guess patience isn't one of my vices... because I've never claimed to be virtuous. Hehe.

In the meantime... the rest of the 7i76E is working, so I've got a 7i78 daughter card that I haven't even looked at yet.  I thought I'd try to use the7i78s four stepgens to replace the four faulty ones on the 7i76e... However, I've run into a few problems as a newbie... and I seem to be unable to set it up. It's plugged into the EXP1 port... and then when I tried to fire up PNCConf....

1. PNCconf apparently has no in-built way to configure the card.. considering this card has been around for a while, I'm honestly surprised. I'd LOVE to help with that. I'm not a coder, but happy to improve some of the documentation, and test features. I've read that some people have managed to install some sort of file to add that functionality, but reliable details seem hard to find.

2. Is there some recipe-like (or newbie friendly, Anschluss styled) instructions for configuring this board from start to finish? I'm having some issues.. with Mesa documentation.

Problem one:

I found the Mesa 7i78 manual quite... incomplete, and unclear. Firstly, if you have a look at:

www.mesanet.com/pdf/parallel/7i78man.pdf

You'll find that TB1 diagram/pinouts on page 5 only goes to pin 12 (and shows only 2 stepgens). Now, I know that there are FOUR stepgens, using a total of 24 pins. Yes, I could just infer that the second set of 12 pins are a repeat of the first 12, but it'd be nice to be sure.

Exacerbating the issue, I find the 7i78 manual wording quite... "round about, and unclear". Case in point:

CABLE 5V POWER
The 7I78 can get its 5V encoder, step/dir and serial interface power from the host interface card if desired. W1 determines if the 7I78 gets this 5V power from the host FPGA card. If W1 is in the left hand position, host cable power is used. If W1 is in the right hand position, 5V power must be supplied to the 7I78 and the 7I78 grounds the 4 DB25 signals used for host 5V power. This option must be set to match the cable power option of the host FPGA card. If the FPGA card supplies 5V, W1 must be in the left hand position. If the FPGA card does not supply 5V, W1 must be in the right hand position.

Can I get someone to confirm that if I've powered my 7i76e with the 24V field power (as the Anschluss diagrams on this forum have indicated) that I can/cannot simply get the power for the 7i78 from the 7i76e? Also, I'm left to wonder where exactly I'd connect the external 5V power to on the 7i78.... I've looked... perhaps the 5V+ and GND on one of the stepgens? I really have no idea, and I'm not going to randomly connect things, hoping it won't blow up.

Honestly, I'll take a photo, or even a wiring diagram written on the back of a napkin at this point. Now I know Linux tech heads are amazing folks able to sort nearly any technical issue out, but I humbly suggest that if we got this info delivered more clearly, people would be able to help themselves more, and let more experienced folks to get onto more important things.

Problem 2: Firmware availability

Mesanet's firmware download link gives me a 404 error. The forum searches here state "I found the files on another user's thread". (No link provided), and I've been completely honest about my newbie ways, so I have no idea whatsoever about what to do at this point. Yes, I did read all 1000+ pages of the LinuxCNC manual a year ago,but I simply don't remember it all, nor do I have a solid understanding of HAL yet. (It still feels like I'm beating my head against a wall, truly... and yet I foolishly keep trying whenever I have time).

Problem 3 (not with Mesa's documentation): Does anyone have a working example of the HAL/INI files for a 7i76e/7i78 combo to run/reference the stepgens? If anyone has used the 7i78 RS422/Spindle/Encoder/Outputs for something... please feel free to put that up somewhere public too. If only to reduce repeat questions.

I'm honestly flying blind running on partially-remembered bits of half-understood notions. The failing stepgens, lack of replacement card options, and time away from this project have been a three-hit sucker punch to my progress, and while I don't want to pester anyone, I'm honestly losing confidence in my choice/ability to use LinuxCNC. All I want to do is get a few steppers running, with a few limit switches, and a couple of relays. When I keep running into obstacles, I keep asking myself:

"Why is this so complicated?"

Sorry for my somewhat existential crisis, but if we can make it just a little easier, I think everyone here would be better off.

As always, have fun, and if you have the time, any guidance would be greatly appreciated.
Hamish.

EDIT : fix 7I78 Stepgen numbers

Mesa can issue a RMA# on Monday

The firmware is available from the Mesa website
(in the Anything I/O FPGA card section, scroll down to 7I76E):

www.mesanet.com/software/parallel/7i76e.zip

or the store:

store.mesanet.com/

search for 7I76e, click on picture and select specifications tab


7I78 TB1 and TB2 pinouts are in 2 columns both show all 24 pins

Typically the 7I78 uses FPGA card power (W1 Left)

FPGA card power for expansion boards is always 5V
( see page 3 in the 7I76E manual)

To use a 7I78 you would need to install the proper firmware and the edit the hal file
to change the stepgen numbers for all hal pins/parameters for stepgens 0..3
to stepgens 5..8 (the stepgens on the 7I78)

Since these ranges of numbers do not overlap, this is pretty simple and can
be done with global replace commands.

That is, replace all "stepgen.00" with "stepgen05", all "stepgen.02" with "stepgen06" etc

 

Hi PCW,

Thank you, truly! Putting several steps together (and reminding me to look at the 7i76e manual) is a big help.

This post may take a few minutes to read... but I'll try to keep it helpful to others.

Just letting you (and anyone else reading this thread) know, that there's a version of the 7i78 manual out in the wild, where the second column is missing on page 5. (See attached). I'm using a Mac keyboard (sans printscreen key) so I've just hit "print PDF" on the the relevant page to save you time.

I've re-downloaded the 7i78 manual from Mesa's page, and it does indeed have the second column. Strange, I honestly thought I had downloaded it from there. I freely admit that I am wrong.

To answer the obvious question, "Where did you download this from?"

I'm sorry, I just don't know. Clearing history after noting some sluggish behaviour after a Firefox update didn't help.

I retract my criticism of the lack of stepgen pinouts in the manual, and I humbly apologise to Mesa's manual writer(s) on this point.


That said, I stand by my criticisms of the 7i78 manuals wordiness. Also, the lack of:

- Any information whatsoever "Refer to parent control card manual" for firmware and configuration.
- Any info about the firmware requirement, or installation process.
- Any info about "This card cannot be configured through PNCConf".
- Any info about the HAL/INI configuration files, or examples.

Makes me wonder.... "Is this really, a manual in the strictest sense?" It seems more of a technical specs sheet to me. It really only covers the jumper settings... even that left me scratching my inexorably-balding head.

Also the 7i78 firmware on Mesanet page:

store.mesanet.com/index.php?route=produc...t_id=121&search=7i78

is a dead link, still rendering error 404.

May I also humbly suggest to the good folks at Mesa... the benefits of placing the relevant parent card firmware for the 7i78 card on the 7i78 page? (perhaps as a zip file of several firmware versions for each compatible parent card) Or even say "Hey, the firmware to run this thing is likely on the page for your parent control card, whether that's a 5i25, 6i25, 7i76e, 7i76ed, 7i80, or 7i92, etc.

It might seem obvious to some, particularly experienced Mesa users who've worked insanely hard to get their knowledge and skills, but many new people (like me) simply start looking for the exact model of the card I'm installing, forgetting that it's really being controlled by another card. As someone who's installed the near-identical-but-wrong firmware on a DVD drive back in 2003.. bricking the day-old drive, I've been somewhat conditioned to be narrow-focussed (perhaps even narrow minded in this particular sort of case). Sorry everyone!

Honestly, I think Mesa's gear is world-class. I really like the specs, and sheer variety of options, but it's also a double-edged sword because it adds to complexity. Mesa's web site, documentation, is (at times) counter-intuitive and (at times) seems hell-bent on scaring new people/beginners off. I suppose while there's a chip shortage, and no doubt tighter budgetary constraints, Mesa's PR and UX definitely take a back seat... it's understandable. However, once Mesa gets production back on track, I'd love to see the site collate related but often-widely-distributed pieces of information into easier-to-find (and understand) quick start guides. I'd even help with that if I could.

The old adage, "Linux is user friendly, it's just more selective about who it's friendly with".. is certainly true to a point. LinuxCNC is great, and has numerous strengths but I still think the initial learning curve could be considerably.... flattened without relying so heavily on the good folks on this forum. That initial curve can look more like a cliff at first glance. Case in point:

Jeremy Fielding (has his own channel on YouTube) built himself a CNC table saw, plasma cutter (I think) and even a robotic arm. He discussed his choice of CNC software (and consequently, hardware) in one of his videos (I can't remember which, he has many) and he summed up his experience quite well.

I'm paraphrasing here, but he said something along the lines of "I looked at LinuxCNC, but it just wasn't for me".

Ok, he's being quite diplomatic there. He didn't lie. When I first looked at it (and I have a strong Linux-certified background) even I'm wondering; "Can I really learn all this HAL/Classic Ladder Stuff? I've got my hands full with learning to design and build a machine, learning to use that machine, and make stuff. All I really want to do... Is just to wire it up, quickly set it up, test it, and go".

Alright, I'll get off my soap box now. Once I get this thing vaguely configured, I'll share my findings and likely, write a step by step instructions on how I did it. Sort of a "Pay it forward and back". Although, if I'm sending my card back to Mesa tomorrow.. it might be a little while.

Thanks everyone, especially you, PCW for keeping me honest. If anyone has a moment of self-doubt, please know that you're not alone

Take care and most importantly, have fun!
Hamish.