Bad servo motor driver

[Bryan Moran]

My laser just developed a problem. It is a Chinese system, model E3525, with an American air cooled 30 watt CO2 laser from Coherent, the model is a GEM (the laser is very nice). The support and documentation on the system is very minimal. The problem is: I was using it the other night when the X axis started “stuttering” occasionally, like it would go into fibulation. Now it does it almost all the time, but snaps out of it occasionally. Same result is that it won’t work and I am trying to turn out product here at Christmas, ouch. I switched the X and Y axis on the driver board and the problem switched, so it is the board, not the motor. Okie Dokie, now what? So I went online to give myself a crash course in stepper motors and stepper motor drivers. I have NEMA 42BYGHW811-05, 2.5 anp, 1.8 degree per step motors http://www.phidgets.com/products.php?category=23. The driver board is not obviously marked but it is a two axis driver with a USB connection to the computer.
So I want to find a replacement board. Here is one http://www.phidgets.com/products.php...duct_id=1063_1 but it is out of stock (AHAHAHHAHAHAHAHHHHHH, so funny) and it is the only one I can find. So my question to the Sawmill creek forum is, does anyone know of a 2 axis driver board (or more axis’s) that can drive a bi-polar (that is what I feel like right now ) 2.5 amp stepper motor? Also it needs to be USB as I am controlling my system with a lap top, not a parallel port from a desk top. And my software is woeful, it is Newlydraw, I am very thrifty (cheap) and am afraid a new motor driver would not perhaps seamlessly interface with my software. I have been thinking about an upgrade anyway and this may force it, what do you think would be a good replacement?

This is my first post, I have been looking for a while and have always found this forum to be very useful. Thank you in advance for any responses you might have.
Bryan Moran

[Ross Moshinsky]

I'm a bit confused.

Normally a motor driver board connects to a break out board (BOB) where you will find a communication port. The other option is to have an "all in one board" where the drivers and the BOB are one piece.

What you've linked seems to be a 1 axis driver/BOB combo. I'd imagine you need a 2 axis setup or you need one stepper motor board which will connect back to the BOB. I believe most Chinese machines use a motor controller board and connect everything back to a BOB. If I'm right, something like this: https://www.probotix.com/stepper_mot...vers/SideStep/ should work. If I'm wrong, something like this http://www.planet-cnc.com/ might work

The best thing to do would be post pictures. I also suggest hitting up CNCZone as it's a really great resource for these types of questions. I wouldn't focus on the laser section but the DIY CNC machine section should have a plethora of information.

[Doug Griffith]

I can't say I have an answer for you but check out arduino.cc and geckodrive.com

[Mark Sipes]

Hope this helps


http://www.active-robots.com/phidgetstepper-bipolar-1-motor.html

[matthew knott]

defo get some photos up, especially the connection for the motor to the board, if a single card solution then you cant just buy a stepper driver with a usb conection to fix it you would need the whole card or work out where the step and directions pins are on the broken card and feed then into a new driver, also lots of the chinese lasers use 3 phase stepper motor as they give a smoother output to 2 phase, sounds like yours is a 2 phase as its 1.8 deg.

[Richard Rumancik]

Bryan, obviously the right solution to to buy the correct replacement board - I assume that this will take too long to get to do your immediate work? Did you improt the laser yourself or buy from a distributor? Seems to me that the distributor should be accomodating even if it means pulling a board out of a stock machine for you. It would be pretty hit and miss to find an off-the-shelf replacement that would not require an EE and a couple days work to reverse-engineer the existing machine. (I'm assuming that you don't have wiring diagrams or schematics.)

It is conceivable that the existing board is repairable; might be worth considering if you can get a technician to take a look. It won't save you any money though compared to replacing the board; just might buy some time. Hopefully there aren't any programmed chips on the board. Could be somthing simple like a bad cap on the power input.

If it is intermittent, maybe there is a bad chip on the board. Anything running too hot? (Hotter than the other board?) Maybe some cool air might keep it happy until you can replace the board. Do a visual inspection first for damaged connectors or suspect solder joints.

Personally I think it is a mistake to try to redesign this machine as it could end up causing more damage. I'd concentrate on getting the correct part.

[Gary Hair]

it could end up causing more damage. I'd concentrate on getting the correct part.

I'm inclined to agree. Do you have anyone who could help you get your order out while parts are being shipped?

Gary

[Bryan Moran]

board.jpgRoss,
First of all thank you for your reply, I appreciate very much your help
Yes, I should have posted a picture. I have now. It is an “all in one” type system. I think your right, I should get a 2 axis all in one replacement. I posted that link to a single axis as that is all I could find, sorry for the confusion. The link you sent also does not have any two axis all in ones, but it does look like the right kind of driver. Know of any 2 axis solutions?
Thanks,
Bryan

[Bryan Moran]

Mark,
Thank you for your reply, I appreciate your help. Unfortunately that is out of stock, and only a single axis.
Thanks,
Bryan

[Bryan Moran]

Richard,
Thank you for your information packed response. I got the sytem used, but brand new, about 2 hours on the machine. A company bought one for a sample to see if they wanted to put them in their stores. They decided to not go with this model and I got it on Ebay for a ridiculous price, no one was bidding on it as it looked a little different and they had zero feedback. So as far as I know there is no distributor. Here is a link to the laser and picture http://www.etl-laser.com/english/cp-view.asp?id=106
Laser-Engraving-Machine-ETL-E3525-.jpg
It is not a question of temperature as it does it right on startup. The system looks very simple. I looked the board over well but I could not see any obvious issues. I think it would be easy to replace. But that is normally what you say before you make a big mistake, so yeah, a replacement sounds like a great idea. I have contacted the company via the web but no response yet. As long as the board responds to USB commands, controls the bipolar motor at 2.5 amp, 1.8 degree rotation, and has two axis, I think it will be okay.
Thanks for your reply. Know of any boards?
Bryan

[Rodne Gold]

You can replace the motherboard (you will need a LCD panel as well) if your steppers have drive modules that are NOT integrated into the main board. The motherboards like leetro and RDLC320 are all configurable for just about any machine and tube. Cost would be circa $500 minimum (motherboard/lcd panel)

You would also have to get software with the board , but thats normally included. RDLC board uses Rdcam/phcam/laserworks and leetro can use lasercut.
It may not be worth it tho , the better option may be to sell the RF tube for $3k or so and buy a complete cheapy machine or even to get a 2nd hand expensive mainstream machine without a tube and install the coherent (if it used a coherent in the 1st place).

[matthew knott]

by the look off that board it defo has the stepper drives intergrated into the main board, if you can contact the manufacturer and get a whole new board then its a quick fix. Also if you can find someone with a electronics bias near you they might be able to fix it, if its just the stepper drive part then its an easy fix as it will be using an intergrated stepper driver chip, these will be bolted to those large heat sinks, if its the step and direction signals palying then your getting into the dsp and cpld parts of the board and thats going to be hard to fix. I would have a good look around all the solder joints near the motor conectors and parts in that area, a dry joint on one phase will casue the motor to become irratic, if you can solder just run round the joints with a iron and some fresh solder. this might be all it needs as stepper drivers are normally pretty bulit proof. Do you know any one that has an Osciliscope (that can use it)? if so can tell you what you need to check.

[Richard Rumancik]

I didn't realize that the drives were integrated into the mainboard, since you were showing a pic of a standalone driver. It would have been hard enough to find a substitute for a standalone board; it would not be advisable to try to attempt to diasble the on-board drivers on the mainboard and patch in a separate driver module. If you had ALL the schematics, plus access to an EE and a week of time MAYBE it could be done. But it would not be a cost effective solution nor reliable. It is possible that the drivers are using off-the-shelf driver chips and if so the main board may be fixable. Again, it will take a bit of work but not nearly what it would take to patch in a third-party driver.

As you say you did not pay much for the machine then you don't have a lot invested, so buying a whole new mainboard is still reasonable. Don't discard the old board as it could still be fixed, or used for parts.

Keep trying to get hold of the manufacturer and see what they can do for you. Maybe you could buy a new board and get them to fix the old one as a spare.

I am not a fan of integrating motor drivers on the mainboard for a number of reasons, but a lot of manufacturers seem to do it. I guess it saves a bit of money. My Mercury uses the same method. I'd rather see separate driver modules or at least a separate three-axis module (x,y, and rot).

[Ross Moshinsky]

board.jpgRoss,
First of all thank you for your reply, I appreciate very much your help
Yes, I should have posted a picture. I have now. It is an “all in one” type system. I think your right, I should get a 2 axis all in one replacement. I posted that link to a single axis as that is all I could find, sorry for the confusion. The link you sent also does not have any two axis all in ones, but it does look like the right kind of driver. Know of any 2 axis solutions?
Thanks,
Bryan

I'd look at this board: https://www.probotix.com/index.php?v...product_id=145

Getting the board from China is obviously ideal but that will most likely take 2 weeks and since you need it this week it seems, you might be able to get the above board to work.

[Glen Monaghan]

Do you know any one that has an Osciliscope (that can use it)? if so can tell you what you need to check.

Better be careful about putting a regular (grounded) o'scope on the circuitry... Often times, the power driver connections are not referenced to ground, so connecting a grounded scope's leads across the outputs of that sort of arrangement causes a short circuit that can almost instantly burn out the driver circuits or, if you're lucky, just blow fuses or shut down the power supply.