Spindle index

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19 Jul 2017 19:45 #96097 by russkinch
russkinch replied the topic: Spindle index
I think hal scope is running in base thread but I will check in morning. I did manage to get a square sign but that was using phase-b. I did not a few things before I left work in case they make sense to you:
encoder.0.counts is at 11447 and increases when I turn chuck by hand
encoder.0.counts-latched is -437
encoder.0.index-enabled is always false
encode.0.position is at 255.0667 and increases when I turn the chuck by hand. However, I thought 1 revolution would be 360 however it increases only by about 7 in one full revolution.
encoder.0.position-latched is -9.711111
encoder.0.position-rawcounts is at 11915

i tried M3 and M4 but no difference. I have changed all the O words that I got of this site to M4 from M3 as my chuck is not a backtool and my chuck turns anti-clockwise
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19 Jul 2017 21:43 #96105 by andypugh
andypugh replied the topic: Spindle index

russkinch wrote: I think hal scope is running in base thread but I will check in morning. I did manage to get a square sign but that was using phase-b

Do you mean the phase-b signal, the B-phase parallel port pin or the encoder.0.phase-b pin?



[quote[encoder.0.counts is at 11447 and increases when I turn chuck by hand[/quote]If you have encoder.0.phase-a connected to the parallel port A-phase pin then that means that the scale is correct _and_ that the A-phase opto is working.
But you seem to be saying elsewhere that none of this is true?

encoder.0.index-enabled is always false

It will be unless motion sets it to true prior to a threading pass. You can set it to true if you want, then see if it goes false. (in a terminal, halcmd sets index-enable true)

encode.0.position is at 255.0667 and increases when I turn the chuck by hand. However, I thought 1 revolution would be 360 however it increases only by about 7 in one full revolution.

It should increase by 1 for a full revolution, if the encoder scale is set correctly.

i tried M3 and M4 but no difference. I have changed all the O words that I got of this site to M4 from M3 as my chuck is not a backtool and my chuck turns anti-clockwise

M3 turns the chuck anticlockwise on a front-toolpost lathe. The reason that M3 M4 makes no difference is because you are using the "abs" version of spindle speed. Do you have any sort of spindle-reverse configured?
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20 Jul 2017 18:04 #96156 by russkinch
russkinch replied the topic: Spindle index
Ok....yay!!!! I am making progress. After reading a lot of what you said and also pages and pages of goole I found that my encoder.0.position-scale was set correct to 45 (number of slots) but my custom_postgui lowpass.0.gain was set to 0.001. I changed this to 1 and I get a nice square wave form. I can also thread cut!! But I think the optocoupler is very slow as the maximum speed I can thread at is 285RPM, after that the motors make some funky noises and the RPM display becomes erratic. Can to tell me what I need to buy to make one of the readers that you use. I can get the sensor for RS component, I can also get the diodes etc from maplin down the road. Anything else?
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20 Jul 2017 18:17 #96157 by andypugh
andypugh replied the topic: Spindle index
In the HAL file you posted the lowpass wasn't even used. And that should have _absolutely_ no effect on the A-phase signal.

Unless... Please tell me you are not lowpass-filtering the encoder pulses?
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20 Jul 2017 18:53 #96163 by russkinch
russkinch replied the topic: Spindle index
um... I actually have no idea as I just used the stepconf to generate the hal file. What should I look for to comment out or delete. The lowpass is in the custompost hal file
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20 Jul 2017 19:32 #96169 by andypugh
andypugh replied the topic: Spindle index
Can we see that file?

I am completely baffled, as you seem to be saying that you have no A-phase but the encoder still counts.
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20 Jul 2017 20:15 #96175 by russkinch
russkinch replied the topic: Spindle index
Sorry. I think there is some confusion. I wrote the hal file like you said, uncommenting the phase-a and phase-b. I made sure the encode.0.position-scale was set at 45 like my wheel. I then checked the custom_postgui.hal file and found a line that says setp lowpass.0.gain. This was set at 0.001 and I change it to 1. I now have a square sign on the hal scope for both phase-a and index, but phase-a terminates at 285RPM and goes to 0. Should I maybe create a whole new stepconf for my lathe and see if it makes any difference. I am using axis with pyngcgui (containing the sub routines from here)
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26 Jul 2017 11:48 #96459 by andypugh
andypugh replied the topic: Spindle index
What does the lowpass filter filter?
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07 Aug 2017 16:42 #97111 by russkinch
russkinch replied the topic: Spindle index
To be perfectly honest, I have no idea. Its what the stepconf automatically writes when I go through all the processes. I can screw cut. Just at 275RPM. Not ideal speed for steel but mainly doing ali at moment. I wonder if maybe the sensor cant read fast enough. Maybe I should make one like you made and see if its any better??
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07 Aug 2017 17:08 #97114 by andypugh
andypugh replied the topic: Spindle index

russkinch wrote: To be perfectly honest, I have no idea. Its what the stepconf automatically writes when I go through all the processes. I can screw cut. Just at 275RPM. Not ideal speed for steel but mainly doing ali at moment. I wonder if maybe the sensor cant read fast enough. Maybe I should make one like you made and see if its any better??


It could be a slow (or heavily debounced) sensor. It could be a slow break-out board. An oscilloscope is the only way to be sure, I think.

There are filter caps on the sensor board, IIRC. You could try shorting across them to see what happens.
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