EMC2 and Stepperworld FET3 Controller

[kbeard]

I have built a homemade CNC and purchased the Stepperworld FET3 controller kit. I'm trying to set up EMC2 to control the CNC.

What a mess. I'm new to Linux and thought that the EMC2 software would be the way to go.

Issues:

1) I've got high latency on the computer. 400,000!!! It's an older computer bought just to run the CNC. I've installed the 8.04 version of Ubuntu and running through LPT1.

2) I can't make head nor tails of how to set up the pinouts for controlling the motors. They make noise (screaming) but there is no rotation when the motors are tested in EMC2.

3) Of course the Stepperworld FET3 control isn't listed in the configuration settings. I've tried most everything I can think of.

If you choose to reply, remember that I'm just starting out and know nothing about anything!

Thanks for any help.

Kevin

[mauve_alert]

Hello Kevin,

Sounds like you're having fun. Okay, regarding the issues ...

1) latency. At first I was going to adress this one, but since you say you're new to linux maybe just first do numero duo. Ofcourse a latency of 400 us is going to seriously limit your stepper speed, so has to be fixed if any actual work is to be done. But 400 us latency is not going to be a problem while doing some slooooow speed jogging of the axis.

2) The pinout ... I hope you do have the pinout of the FET3 kit? If you know that one, it is a simple matter of configuring the right pinout in the right config file.

On the emc side you can configure the parport pinout in a file like for example EMC_DIR/configs/stepper/standard_pinout.hal

The default is something like

# standard pinout config file for 3-axis steppers
# using a parport for I/O
#
# first load the parport driver
loadrt hal_parport cfg="0x0378"
#
# next connect the parport functions to threads
# read inputs first
addf parport.0.read base-thread 1
# write outputs last
addf parport.0.write base-thread -1
#
# finally connect physical pins to the signals
net Xstep => parport.0.pin-03-out
net Xdir  => parport.0.pin-02-out
net Ystep => parport.0.pin-05-out
net Ydir  => parport.0.pin-04-out
net Zstep => parport.0.pin-07-out
net Zdir  => parport.0.pin-06-out

Which is fairly self-explanatory really. Check in your BIOS if LPT1 is assigned to port 0x378, and adjust accordingly. (probably correct since you do get a lot of noise from the steppers, i.e it is doing something). By the sound of it you may have to edit the Xstep, Xdir etc pinouts according to what your FET3 documentation says.

After you have configured that, you should be able to do some sloooooow speed jogging to see if the connections are right. After that it's time to do something about that latency.

Hope that helps,
Fred

[kbeard]

Well, I'm learning!

Latency - I discovered an add-on usb port in the back of the computer and removed it. Also shut off a few things in the bios. (Finally figured out how to access it!) My latency went from 400,000 ms down to 10,800 ms. Cool!

Got the pinouts figured out. I set the pins which turn on the x/y/z enable to "Charge Pump" !!!!!!!!!! Can you believe that? Seems to work, however, it's still guesswork.

It turns out that the EMC2's configuration page does nothing more than organize the pinouts on the next page and control a few other things on the first page.

----------------

Ok, new question...

Now that the motors are working, I seem to have a new problem.

I started out with an acceleration of 3 and a velocity of 2. No go!
The motor sounds like it should be working (high pitch whining) but the shaft does not move. If I change the velocity to 1 the shaft begins to turn but stops rotating as the motor winds up to full speed. A velocity of .2 ips (POINT TWO!) will allow the motor to rotate and not miss steps but of course it's very slow!

I think that this is a problem with EMC2's "Microstepping". I know that the Stepperworld is not a Microstepper. The controller was shipped with the dip switches set to "Hi Torque". Last night I switched the controller to "Half-Step" thinking that would solve my problems. It didn't.

Now, for some reason, my X Axis has stopped responding. I'll check the wiring tonight. (Oh, I hope I didn't blow a circuit!)

Any help would be appreciated.

Kevin

[mauve_alert]

Good thing you got the latency/smi fixed!

The motors doing a lot of whining may well have to do with the fact that you are using that "Charge Pump". If I remember correctly that charge pump pin you've got there is an oscillator with something like a 10 kHz frequency. So if I understand your setup correctly you are now modulating your step signals with a 10 kHz enable, which I doubt the stepper driver will like very much. Hence the whining.

Maybe what you are looking for is the Xen, Yen and Zen signals for x,y,z-axis enable. You can use those on the pins where you now have charge pumps.

Config file snippet:

net Xen  => parport.0.pin-RTFFET3M-out
net Yen  => parport.0.pin-RTFFET3M-out
net Zen  => parport.0.pin-RTFFET3M-out

Hope that helps,
Fred

[kbeard]

Worked on the machine again last night.

I figured something was up with that "charge pump" thing.

I switched the fields to "Spindle On" and the X-Axis magically started working again. I then went through all of the EMC2 drivers listed (with their varying "Step Time") variables and had pretty much the same results as before.

A few of the drivers would allow the motor to turn at VERY SLOW speeds but most all of them would just "Grunt, Growl, and Howl". I tried each driver at 8, 4, 2, 1, and .5 microsteps. The lower microsteps on a couple of drivers would allow the motors to turn at a velocity of .1 ips but nothing at the higher velocities.

I am frustrated that EMC2 doesn't have a pinout variable called "X Enable".
I'm left trying to guess which of the available variables might work.

I'll try the last post's suggestion tonight.
Wish me luck!

PS - To all you "Newbies" -
Quit trying to "be a man" and read all the directions!

[johnmac]

kbeard, did you get a CD with your FET3 controller? If so, it will have some configuration information for EMC2. I think its in a folder called DOCS.

The field effect transistors used in the FET3 have rather slow switching rates. Don't expect fast motor rpms.

John

[kbeard]

Yes, I've read all of the files on the CD.

There is one file in the SP3 subdirectory called "EMC.ini"

I have looked at it but it's an "ini" file for the old version of EMC.

About half of the variables in the file are also found in EMC2.
The other half of the variables are missing.
Tonight, I'm trying to figure out how to fix this.

Evidently EMC2 is set up to use a file called "motmod.ko" whereas the older version of the ini file calls for "steppermod.o" which doesn't exist anywhere on the harddisk. I've tried switching the callout to "stepperdef.ko" (???) but it returns an error from the "my-mill.hal" file. Can't recall the actual name of the file since I'm not in the basement. Any help???

I'm gonna fire off an e-mail to StepperWorld about the outdated ini file.

Uff-Da!!!

[johnmac]

Russ seems like a good guy. He should be able to help you out.

John

[lumberjack_jeff]

Originally Posted by kbeard I have looked at it but it's an "ini" file for the old version of EMC. About half of the variables in the file are also found in EMC2. The other half of the variables are missing. Tonight, I'm trying to figure out how to fix this.

Be aware that the ini file which is created by stepconf (the EMC configuration program) does not include entries for the entire universe of possible parameters.

There are a lot of parameters (e.g. "backlash") which are not written to the ini file by stepconf.

Check out the integrator's document.

[chester88]

Originally Posted by kbeard Worked on the machine again last night. I figured something was up with that "charge pump" thing. I switched the fields to "Spindle On" and the X-Axis magically started working again. I then went through all of the EMC2 drivers listed (with their varying "Step Time") variables and had pretty much the same results as before. A few of the drivers would allow the motor to turn at VERY SLOW speeds but most all of them would just "Grunt, Growl, and Howl". I tried each driver at 8, 4, 2, 1, and .5 microsteps. The lower microsteps on a couple of drivers would allow the motors to turn at a velocity of .1 ips but nothing at the higher velocities. I am frustrated that EMC2 doesn't have a pinout variable called "X Enable". I'm left trying to guess which of the available variables might work. I'll try the last post's suggestion tonight. Wish me luck! PS - To all you "Newbies" - Quit trying to "be a man" and read all the directions!

First thing is I am assuming you are using stepconf to make a configuration.

-the signal name you are looking for to enable the step drivers is 'ENABLE AMP'
which means enable amplifier (or driver)
you can have multiple enable amp signals if you want an enable per axis.
- microstep setting will not make the motors miss steps it will only make it move the wrong amount of steps. I think you said you could set the driver to half stepping, then the microstepping should be set to 2. quarter stepping would be 4 etc.
- driver timing, acceleration, max velocity and base period all effect miss stepping and top speed.
- make sure the wiring is right. That means to the step driver and to the motors. If the motor wires are wrong it will never step properly.
- try setting all the driver timings to 2000 and acceleration low then test.
when you figure out driver timing that works add it here so other people know:
http://wiki.linuxcnc.org/cgi-bin/emc...r_Drive_Timing

[kbeard]

Thanks for the responses.

Did some more work on the machine tonight and made a little progress. I'm convinced that these little steppers just don't have much "umph". No matter what I set the velocity, acceleration, step time, etc, the motors sound like they should be spinning but no rotation.

If I reduce the velocity to .1 ips the motors will spin (slowly) without missing a beat. Change them to .2 and forget it. Noise but no rotation.

Can somebody tell me how powerful the Stepperworld FET-3's are. I think they are rated 100 oz. When spinning, I can place my fingers on the pulley and stop the motor with a little squeeze. They don't seem to have much torque at all.

I did some realignment of the bearings / screw threads to get the lead screw to turn as easily as possible. Now I can run the X axis with the velocity set to .1 ips. Takes about a minute to travel an linear inch. SSSLLLOOWWW !!!

I was hoping for better. Part of the learning curve I guess.

I'm not sure what to do next. Do I have the Stepperworld FET-3's configured correctly and they're just whimpy. If that's the case, do I rework the machine for easiest (slow) travel. Or do I plunk down more money on stronger motors, higher voltage supply, different controller??
Can anyone make suggestions?

I was hoping that this would be a better experience...

Kevin

[johnmac]

The FET3 CD has a Windows based program that will you to run the motors without control software. Running it will tell you if the problem if hardware or software. If it is hardware, first double check that the motor winding are indeed wired correctly. While the FET3 board is slow, its not anywhere near that slow. I have one on my first machine.

John