only fast steps chinese6040

I have a chinese 6040 3-axis machine with a blue control box w/ estop and waterpump (disabled/not used: causes feedback over steppers) and an 800w watercooled router and VFD. This is my first CNC machine.

I am controlling it with a device called rtstepper (usb to buffered, stepped Parallel) from www.ecklersoft.com/
Via on a win7 x64 computer (& x32 TCL)
RTStepper uses a version of LinuxCNC running a TKmini frontend, and should follow the same configurations, with minor alteration.

As it is a modified version, I get No Wizards for Configuration. The documentation I got, after request, for the machine was all for Mach3. I spent a week unproductively trying to make my machine move and then got a config from the designer of rtstepper. I allows the machine to move, but then I tried to cut something:

The machine will move to the fast motions (move from origin to first cut), but then only kind of twitches (like it is trying to move, not spastic; i think) the steppers, instead of moving and following the G-code, all axes. After 15 minutes of what should have been a lithograph, all i had was a dot about 1mm in diameter (the machine just twitched there instead of moving along). I check the g-code, and it isn't the problem. Also of note, I don't see a hal file for the program. I don't think it is actually necessary, but I don't know much. People mention changing step values/timings, which works great...If you have the config wizard! I don't see anywhere to change that in the ini other than by complicated extrapolated values.

If I understood better, I would just modify the config myself, but I obviously don't if I couldn't get it to run in over a week of pouring through forums and guides. Would some more knowledgeable individual please modify the attached rtsteppper-cncforums.ini to something that should work. I would really appreciate it.

I've got to get some pieces cut soon to meet deadlines. I care far more about stability/accuracy than absolute speed of cutting operations. I will be cutting Brass, Alu, and wood, with heavy emphasis on the brass cutting.

Attached & below are as many of the machine specs as I have:

Steppers: 3 identical:
57type 2phase 3A 1.8o YOC/57BYGH-76
1605 ball screws (16mm Dia & 5mm pitch)
Control:
110v 3977 3-axis control box
Seperate VFD for spindle control of 800w water cooled rotary
Table working travel:X-400mm x Y-580mm Z-75mm

Setup using mm as units
(was originally sold to use with mach3, so setup info available was for that)

Pin assignments:
SetPin|DirPin|DirLow|StepLow|StepPort|Dir Port|
x: 2 3 no yes 1 1
y: 4 5 no yes 1 1
z: 6 7 no yes 1 1

Estop:
Port#|Pin#|Active Low|Emulated|
1 10 yes no

Motor Tuning:
Steps/rev|V(mm/min)|A(mm/sec^2)|StepPulse(1-5us)|DirPulse(0-5)
X: 400 2000 200 10 3
Y: 400 2000 200 10 3
Z: 400 800 100 10 3

Hi

I'm afraid that rt_stepper is a commercial product, the software for which was based upon a much cut down version of EMC2.
It is not Linuxcnc and this forum does not support it.

To quote his site

The rt-stepper software is based on the EMC2 open source project at www.linuxcnc.org. Note both projects are separate software applications and the dongle will only run on the rt-stepper software

I assume you have read the manual www.ecklersoft.com/ers.html#configuration
It does tell you how to set up the .ini file, calculate input scale etc.

If that does not cover your needs you really have to take it up with eckersoft, as they sold you the dongle.

The ini file you attached is the sample one on his site and in the tarballs.
It diverges from the Linuxcnc .ini file and references two .hal files which are not supplied.
There is no information regards the extent to which rt_stepper uses hal or which parts of it are retained.

Sorry but there it is, if you want to ditch the dongle and run your machine from a parport with Linuxcnc, then we can assist you

regards

Well to start you can try reducing the velocity and acceleration in your ini file.

TYPE = LINEAR
HOME = 0.000
MAX_VELOCITY = 33.33
MAX_ACCELERATION = 200

Rick G

I appreciate the input. FYI, the software for running rtstepper is opensource and can be used for any stepper (assuming someone wanted to make another). The actual stepper does cost money (but of course, making objects isn't free). The software itself is some stripped down version, and as such should be easy for someone experienced to recommend proper alterations to my ini.

---

Yes, you seem to be correct, only it isn't the G-code itself: I ran a test with a 10"x10" square design and it produced a 1.25"x1.25" square actual (using mm G-code). (running SAE G-code has smaller numbers than metric, and it seemed to be stuck in a range that didn't move enough to actually move positions during cutting).

I hauled my big desktop down and tested with mach3's demo mode. Not only did it cut way faster, it also seemed to prove that the problem isn't the g-code itself, rather the config for the rtstepper. I don't actually even know if I'm supposed to use mm or inch based G-code with rtstepper, though I would assume it wouldn't matter with proper scaling.

What parameters should I change to account for this 10:1.25 ratio? (and if you don't mind, what should they be changed to?)


It would be nice to have a graphical preview, but once it is running, that is trumped by being able to do everything on 1 modern computer. Tradeoffs. So far, it has mattered far more that I am lacking the configuration wizards than anything else.

What parameters should I change to account for this 10:1.25 ratio?

In Linuxcnc the SCALE parameter is adjusted. It is the number of steps to move one unit of measurement.


Rick G

From the link you posted...

NPUT_SCALE define the stepper motor steps/inch for this axis. This is a function of your motor, lead screw and CNC controller. Metric values can be used here instead of inch.

Here are some notes on how to calculate the INPUT_SCALE for a Sherline mill using the using a Xylotex 3-axis CNC controller and 269 oz.in steppers.

1.8 = degrees/step
360 / 1.8 = 200 steps/revolution
.050 = one revolution of the lead screw
200 / .050 = 4000 steps/inch full steps

Since the Xylotex CNC controller board is set to 1/8 stepping.

4000 * 8 = 32000 steps/inch = INPUT_SCALE

Thanks Everyone,
Setting Input_Scale= 640 solved everything. I runs fast and I get the right size of parts (using mm based G-code).

Also thanks, Rick G, for showing the calculations and parameters I should be messing with. There is so much information, I get information overload. That helped my understanding quite a bit.

Glad you got it sorted out.

Rick G