7i76 using a spindle encoder input for index axis0
25 Jun 2016 13:54 #76648
by finemeca
Replied by finemeca on topic 7i76 using a spindle encoder input for index axis0
An idea...
On the drive, I have a OCZ into open collector.
If I do this:
OCZ ---> relay ----> net x-index-enable hm2_5i25.0.7i76.0.0.input-00
What do you think ?
On the drive, I have a OCZ into open collector.
If I do this:
OCZ ---> relay ----> net x-index-enable hm2_5i25.0.7i76.0.0.input-00
What do you think ?
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25 Jun 2016 15:41 #76649
by PCW
Replied by PCW on topic 7i76 using a spindle encoder input for index axis0
Index-enable is something linuxcnc controls to enable encoder count latching on
index
Indexed homing cannot be done without a full encoder input
index
Indexed homing cannot be done without a full encoder input
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25 Jun 2016 15:49 #76650
by finemeca
Replied by finemeca on topic 7i76 using a spindle encoder input for index axis0
Ok you have another card that 7i76 reference works.
just to use an encoder
just to use an encoder
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26 Jun 2016 18:11 #76680
by finemeca
Replied by finemeca on topic 7i76 using a spindle encoder input for index axis0
One solution may be to use the parallel port and parport.
So I'm a encoder and I use his entry for the net x-index-enable.
OK ??
So I'm a encoder and I use his entry for the net x-index-enable.
OK ??
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26 Jun 2016 19:38 - 26 Jun 2016 19:39 #76683
by PCW
Replied by PCW on topic 7i76 using a spindle encoder input for index axis0
I think there is a misunderstanding of what the index input and index enable do:
1. index enable is an internal signal to linuxcnc used to enable index latching
of the encoder count when the index signal is detected
it is not useful to get the index-enable from an external source
2. The index input causes hardware/linuxcnc to capture the encoder count when
index signal is detected. If you want to use homing on index you must have a servo system
setup with encoder feedback. For a lathe this probably means 3 encoder inputs
(9 signals if all encoders have A,B,Z))
1. index enable is an internal signal to linuxcnc used to enable index latching
of the encoder count when the index signal is detected
it is not useful to get the index-enable from an external source
2. The index input causes hardware/linuxcnc to capture the encoder count when
index signal is detected. If you want to use homing on index you must have a servo system
setup with encoder feedback. For a lathe this probably means 3 encoder inputs
(9 signals if all encoders have A,B,Z))
Last edit: 26 Jun 2016 19:39 by PCW.
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27 Jun 2016 08:19 #76693
by finemeca
Replied by finemeca on topic 7i76 using a spindle encoder input for index axis0
ok thank you for these precision.
For item 1:
index enable
What to add hal?
For item 2:
Not usable with my drivers closed loop
For item 1:
index enable
What to add hal?
For item 2:
Not usable with my drivers closed loop
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28 Jun 2016 13:02 #76739
by andypugh
Your idea won't work, I don't think.
I changed my mind (twice).
Normally the system uses the counts since the index reset to calculate the home position, but you could, in theory, use the spindle index input as a pulse-extender to make the very short index pulse visible to the realtime system.
On the hardware side you would need to arrange things such that both the axis index and the spindle index can trigger the 7i76 index input.
The HAL logic might be very easy or might be hard. I don't know how many bidirectional pins you can add to a net.
You won't get all the benefits of index-homing, but you should get something rather more accurate than a simple switch.
Replied by andypugh on topic 7i76 using a spindle encoder input for index axis0
Can I connect this
net x-index-enable hm2_5i25.0.7i76.0.0.encoder.01.index-enable <=> axis.1.index-enable
Your idea won't work, I don't think.
I changed my mind (twice).
Normally the system uses the counts since the index reset to calculate the home position, but you could, in theory, use the spindle index input as a pulse-extender to make the very short index pulse visible to the realtime system.
On the hardware side you would need to arrange things such that both the axis index and the spindle index can trigger the 7i76 index input.
The HAL logic might be very easy or might be hard. I don't know how many bidirectional pins you can add to a net.
You won't get all the benefits of index-homing, but you should get something rather more accurate than a simple switch.
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29 Jun 2016 07:08 #76774
by finemeca
Replied by finemeca on topic 7i76 using a spindle encoder input for index axis0
Ok thank you for that.
This is not simple.
I will first try without this feature.
I do my tests of the tour soon.
Depending on the accuracy, I would tell you.
This is not simple.
I will first try without this feature.
I do my tests of the tour soon.
Depending on the accuracy, I would tell you.
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