Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
20 Aug 2017 10:37 #97768
by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Contemplating to change to another working encoder but this one is for 24VDC, so to make this work I have to use optocoupler and I wonder if PC847 is fast enough? I have boards ready for this type of level conversion.
Problem is that I have no documentation for the encoder so I do not know how many pulses/rev it has.
Problem is that I have no documentation for the encoder so I do not know how many pulses/rev it has.
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20 Aug 2017 11:42 #97772
by andypugh
Replied by andypugh on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Proxes are cheap (but not fast) on eBay.
As I suggested earlier, you can probably fool the system in to working without an index for tapping if you don't need to peck-tap.
As I suggested earlier, you can probably fool the system in to working without an index for tapping if you don't need to peck-tap.
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20 Aug 2017 11:48 #97774
by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
I am all ears Andy how to accomplish the task.
Personally I do prefer to use tapping tools with sliding head to take care of spindle rev down and up.No peck-tap!
The encoder I have is 1000ppr and just now I am 3D printing new holder that can accomodate prox if need be.
Have one Balluf Ø8mm and one Festo Ø12mm that both can do max 3kHz. The new holder will have provisions for both.
Personally I do prefer to use tapping tools with sliding head to take care of spindle rev down and up.No peck-tap!
The encoder I have is 1000ppr and just now I am 3D printing new holder that can accomodate prox if need be.
Have one Balluf Ø8mm and one Festo Ø12mm that both can do max 3kHz. The new holder will have provisions for both.
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20 Aug 2017 12:08 #97777
by andypugh
Replied by andypugh on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
I think that Master has a cycle for tension-compression heads. G85?
Anyway, the first step in working out how to spoof it in HAL is to work out what happens if you just set the index-enable back to zero without zeroing the counts. That isn't a test I can do on hardware because I am on the opposite side of the North Sea from my machines
Anyway, the first step in working out how to spoof it in HAL is to work out what happens if you just set the index-enable back to zero without zeroing the counts. That isn't a test I can do on hardware because I am on the opposite side of the North Sea from my machines
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20 Aug 2017 14:08 #97783
by andypugh
Replied by andypugh on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
I tried this in a sim. Don't try it with hardware.
The Z-axis will attempt to instantly go to the spindle "position" which might be thousands of turns down.
One thing that ought to work is to connect the index-enable signal to a digital output, and then take a physical wire from the output to the encoder index input.
net spindle-index-enable hm2_7i76E.0.digitalout-00
The Z-axis will attempt to instantly go to the spindle "position" which might be thousands of turns down.
One thing that ought to work is to connect the index-enable signal to a digital output, and then take a physical wire from the output to the encoder index input.
net spindle-index-enable hm2_7i76E.0.digitalout-00
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21 Aug 2017 14:28 #97817
by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Just got info from factory here in Sweden that this encoder is 1000ppr.
So my question still is if I go the optocoupler way to get voltages OK, does 1000ppr fit into PC847 specs or do I need
faster optos and if so how fast do they have to be?
So my question still is if I go the optocoupler way to get voltages OK, does 1000ppr fit into PC847 specs or do I need
faster optos and if so how fast do they have to be?
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21 Aug 2017 15:21 #97819
by PCW
Replied by PCW on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Well, a 1000 PPR encoder will output 1000 Hz square waves (500 usec high/low)
at 1 RPS (60 RPM) so you need < 50 usec response time to get to 600 RPM...
at 1 RPS (60 RPM) so you need < 50 usec response time to get to 600 RPM...
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21 Aug 2017 15:45 #97823
by tecno
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
OK so typical rise and fall is 4µs for PC817/847 so it would cut the cake if I have my math correct 
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21 Aug 2017 17:58 - 21 Aug 2017 17:58 #97828
by tecno
Will exchange encoder to one that is working OK and use above to get levels OK.
74HCT14N that I have at hand here.
Replied by tecno on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
Will exchange encoder to one that is working OK and use above to get levels OK.
74HCT14N that I have at hand here.
Last edit: 21 Aug 2017 17:58 by tecno.
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21 Aug 2017 18:08 #97830
by PCW
Replied by PCW on topic Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.
That should work though I would choose say 2K for the low side resistors
so you get a valid 4V high at the 74HCT14 input instead a marginally high level of 2.18V
with 1K
so you get a valid 4V high at the 74HCT14 input instead a marginally high level of 2.18V
with 1K
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