Newall DRO RS-232 XYZ output as LinuxCNC position input
31 Oct 2018 00:22 #119677
by Tek4UFast
Newall DRO RS-232 XYZ output as LinuxCNC position input was created by Tek4UFast
Anyone know if possible to use the RS-232 XYZ positional data from a Newall DRO to provide LinuxCNC with usable position data?
I have a large Wells-Index mill that I am converting to CNC. Seems like using the data from the DRO would be a great option.
Thanks!
I have a large Wells-Index mill that I am converting to CNC. Seems like using the data from the DRO would be a great option.
Thanks!
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31 Oct 2018 10:55 #119694
by andypugh
Replied by andypugh on topic Newall DRO RS-232 XYZ output as LinuxCNC position input
It sounds like it should be possible.
I don't think that you would want to use it as the primary control loop, but you could use it as an extra "tweak" for final position control (you would use two summed control loops, one based on the motor encoders for stable speed and velocity control, then add on a slow-moving I-only controller based on the scales).
The reason i say this is that it seems likely that the serial DRO update rate will be quite slow relative to the 1mS servo-thread update rate.
What does the data format look like? What other control hardware do you anticipate using?
I don't think that you would want to use it as the primary control loop, but you could use it as an extra "tweak" for final position control (you would use two summed control loops, one based on the motor encoders for stable speed and velocity control, then add on a slow-moving I-only controller based on the scales).
The reason i say this is that it seems likely that the serial DRO update rate will be quite slow relative to the 1mS servo-thread update rate.
What does the data format look like? What other control hardware do you anticipate using?
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31 Oct 2018 11:29 #119701
by Tek4UFast
Replied by Tek4UFast on topic Newall DRO RS-232 XYZ output as LinuxCNC position input
Thanks AndyPugh!
I was hoping someone out there has already done this. As for hardware, I have a number of Mesa boards and will lay it out with one. Currently I have the DRO working in X and Z, and one large Stepper moving the table in X. The stepper is running off of switches at a pendant for now but works perfect for a power feed.
I knew the position data from the DRO would be slow compared to that coming off any encoder, but the DRO accuracy is much better. Another question is will the NEWALL Spherosyn scales interface with anything compatible with LinuxCNC?
The Wells-Index is a monster that came out of an Oldsmobile plant. It's a 5hp extra-large table from the 70s I think. Full CNC is just the right thing to do.
Thanks Again Andy ..... any suggestions are welcome.
Bill
I was hoping someone out there has already done this. As for hardware, I have a number of Mesa boards and will lay it out with one. Currently I have the DRO working in X and Z, and one large Stepper moving the table in X. The stepper is running off of switches at a pendant for now but works perfect for a power feed.
I knew the position data from the DRO would be slow compared to that coming off any encoder, but the DRO accuracy is much better. Another question is will the NEWALL Spherosyn scales interface with anything compatible with LinuxCNC?
The Wells-Index is a monster that came out of an Oldsmobile plant. It's a 5hp extra-large table from the 70s I think. Full CNC is just the right thing to do.
Thanks Again Andy ..... any suggestions are welcome.
Bill
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31 Oct 2018 11:46 #119702
by andypugh
Replied by andypugh on topic Newall DRO RS-232 XYZ output as LinuxCNC position input
Which Mesa boards do you have? There is a Mesa UART module, for example, and a number of absolute serial encoder formats are supported.
The RS422 expansion port on a 7i76 would be one convenient place to interface the scales.
The RS422 expansion port on a 7i76 would be one convenient place to interface the scales.
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31 Oct 2018 12:30 #119705
by Tek4UFast
Replied by Tek4UFast on topic Newall DRO RS-232 XYZ output as LinuxCNC position input
I have a 7i76, I have done no investigation yet, are you sure the NEWALL Spherosyn scales are supported for communication.
Thanks!
Thanks!
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31 Oct 2018 12:52 #119706
by andypugh
Replied by andypugh on topic Newall DRO RS-232 XYZ output as LinuxCNC position input
I am sure of absolutely nothing. I am guessing based on your own mention of RS232.
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