Messages

51

Brains Development / Wirting Message to Status Area via Brain

« on: July 16, 2009, 04:13:04 PM »

What is the OEM code to write text to the "Status" area located at the bottom of Mach's Program-Run screen?

52

General Mach Discussion / Re: Resetting Encoder Count Via a BRAIN

« on: May 27, 2009, 11:50:54 PM »

If I understand correctly, Encoder 1 is the encoder that correspnds to the X-axis encoder and OEM button code 133 can be used to zero that encoder count.  I'll give that a shot. Thanks for the help.

53

General Mach Discussion / Re: Resetting Encoder Count Via a BRAIN

« on: May 27, 2009, 08:25:31 PM »

I apologize for not communicating clearly. My ultimate goal is to detect racking of the gantry and stop the machine before damage can be done. The gantry is moved by a lead screw on each side. My plan is to have a rotary encoder at the end of each screw. When I detect that one screw is not keeping up with the other, then issue a stop command. My problem is establishing the inital conditions for each encoder. I am sure there are many ways to solve this problem. My first thought was to detect when the machine is in an e-stop state and then zero each encoder count via a brain. When the machine is taken out of the e-stop state, then have the brain compare the two counts and stop he machine if they differ by more than a few counts.

If there is no way to zero the counts, then my next thought was to read the counts into a variable when the machin is in an e-stop condition. Call these the initial count variables (a variable for each encoder). Once the machine is out of the e-stop condition, subtract the initial count variables from the encoder readings. Again, if these readings differ by more than a few counts, stop the machine.

I am open to a completely different approach. Perhaps I need to assign the encoder to an MPG or axis DRO. Perhaps my newness to Mach is making this a much more difficult problem than it should be.

54

General Mach Discussion / Re: Resetting Encoder Count Via a BRAIN

« on: May 27, 2009, 05:52:22 PM »

In the Ports and Pins screen I have set up Encoder1. Then in the Brain editor I tried to find Encoder1, but could not. I found Encoder0 in the DRO listing. When I turn the encoder, I see the count for Encoder0 change in the Brain.

I am a newb to Mach. Perhaps there is a better way to assign things. I would be glad to assign the encoder to X, Y, or Z so long as it did not affect the machine with respect to the X, Y, or Z axis. I'm very open to any suggestions you have.

55

General Mach Discussion / Re: Resetting Encoder Count Via a BRAIN

« on: May 27, 2009, 05:33:44 PM »

Since there is not an OEM code to zero Encoder0, does that mean you know of no solution?

56

General Mach Discussion / Re: Resetting Encoder Count Via a BRAIN

« on: May 27, 2009, 05:20:21 PM »

There are OEM codes for zero X Y and Z DRO, cant see any for A unfortunately
In the Brain you can have the terminator as a button press then manually type the OEM number into the box in place of the OEM that is there.
Hood

Thanks for the quick reply. Is the last sentence in your reply a solution? If so, can you further explain. If it is not a solution, do you know of a way to write an encoder count to Encoder0? That way I could write 0 to it as opposed to activating a zero button. If that won't work, do you know of a way to write the Encoder reading to a variable while the system is in e-stop. I could then use that value in a formula once it is out of e-stop. Surely there is a way to accomplish this.

Thanks again for your help.
Kent

57

General Mach Discussion / Resetting Encoder Count Via a BRAIN

« on: May 27, 2009, 04:25:07 PM »

I am trying to write a brain that will compare the counts on encoders on each screw of a two screw gantry and issue an e-stop if they differ by more than a certain number of counts. This is used as a control to keep from racking the gantry if a motor starts skipping steps on one of the lead screws. I believe I know how to do this, except for establishing the initial count for the encoders. I would like to zero the encoder counts when the system is in an e-stop condition. There is a "zero" button on the Settings screen (one zero button for each X, Y, and Z encoders), bi I cannot find a brain button to do that. I believe EncoderCnt 0 corresponds to the x-encoder in the brain. I am also a bit confused by the fact that you can configure 4 encoders in the Pins and Configuration screen, but there are only 3 (X,Y, and Z) encoders shown on the Settings screen.

Any help will be greatly appreciated.

58

General Mach Discussion / Step/Direction Pulse Width Default

« on: May 24, 2009, 01:25:54 PM »

In the motor tuning screen, what is the actual pulse width of the step and direction signals if you leave this screen with 0 in these two fields. I am running a SmoothStepper and a CNC4PC C23 BOB. I can spin the stepper motors, so I know the pulse witdh is not truly zero.

59

General Mach Discussion / Re: Racking Detection with Encoders

« on: April 22, 2009, 01:25:35 PM »

Thanks to all for posting ideas. Perhaps I asked this question too soon in my learning curve. I realize when such basic questions are asked that it can be frustrating for others, especially when many things can be answered by documentation that is available. So I need to bone up on writing macros and brains and will then hopefully ask more detailed questions or actually solve it myself. Based on the feedback, it does appear that Mach will handle doing this in software which was really the basic question I wanted answered. I had hoped that this had been done before and someone could point me to a post or have the "easy" answer. I would have thought this would have been solved before. Some have gone to great lengths to mechanically eliminate the possibility of racking.

Thanks again to all!
Kent

60

General Mach Discussion / Re: Racking Detection with Encoders

« on: April 21, 2009, 10:11:20 PM »

Where can I learn about a macropump and the macro language? Sorry for asking such a newb question. I would really appreciate it if someone could post a snipit of code that is a starting point for this problem, such as reading an encoder input, and then describe, or point me to documentation, regarding installing it as a macropump. I'd much prefer this route, assuming it is feasible, as opposed to developing a circuit to do this.