Re: Lets talk about encoders
What are you doing with the encoders? And what kind of motors/drives are you using? Typically, the encoder data has nothing to do with the drives in Mach3.
Re: Lets talk about encoders
currently I'm running some closed loop steppers from leadshine, which have a shaft encoder built into the stepper. I'd like to actually use a linear encoder to replace it the rotary encoder.
Yeah, and I guess I don't understand the relationship between mach3, the drive, and the encoder. I know mach3 has nothing to do with the feedback loop, but how does the drive interperate the signal from mach and from the encoder? logically I would think if mach sent 5 pulse signals, the drive would want to read 5 encoder signals. and any deviation from that is the error read by the drive.
Re: Lets talk about encoders
Linear encoders are all metric as far as I know. Normally available in resolutions of 0.1, 0.5, 1, 2, 5, and 10 microns, this is true for both glass and magnetic scales. 1 micron resolution = 25400 pulses / inch, or 0.000039 inch / pulse.
If you are planning on closing the loop at the drive level, I don't know how a drive would react to being fed with an encoder that it was not calibrated for. Depending on the drive, it may be possible to set the scaling.
To really take advantage of linear encoders, you would need a real motion controller between Mach3 and the drives and close the loop at the controller. Dynamotion or Galil would be good choices.
I have 1 micron magnetic linear encoders on all of my machines and have had very good luck with them.
Re: Lets talk about encoders
Quote:
but how does the drive interperate the signal from mach and from the encoder?
I think that they are two separate loops. Or the steps/unit is locked to the encoder resolution.
Mach3 knows nothing about the encoder. It just sends steps to the drive.
The drive just makes sure the motor goes where the steps have told it to go.
Re: Lets talk about encoders
thanks for the responses guys. I'll take a look at my drivers to see if the encoder is truly configurable or if it's just preset values.
I've never really looked at the dynamotion board as I din't know they had a mach3 plugin. But I wish I had known about it before I bought my smoothstepper boards. haha.
Re: Lets talk about encoders
According to the manual, I can set that to be any value I want. So maybe I'll give that a try first.
but i guess on that topic, what exactly does the drive do with that information? Maybe for this drive it helps determine the microstepping?
Re: Lets talk about encoders
Quote:
Originally Posted by
CS900
.............. what exactly does the drive do with that information? Maybe for this drive it helps determine the microstepping?
Lets say Mach3 sends out 100,000 pulses, that drive takes that information and moves the motor (or table) 100,000 encoder pulses. With the loop closed at the drive, the drive looks at the current position and keeps moving the motor until the 100,000 pulse distance is reached.
Re: Lets talk about encoders
That's what I thought was happening. Seems like the encoder itself it's fairly arbitrary and pretty hopeful I can close the position loop at the drive.
Re: Lets talk about encoders
Re: Lets talk about encoders
there's a link in post #3 to them.
Re: Lets talk about encoders
I would think that the encoder resolution needs to match the one on the motor, or it won't work correctly, as the drive is expecting 1000 counts/rev? (Or is it 4000?)