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Offline Hood

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Question for TechCNC
« on: October 19, 2012, 05:45:06 PM »
Hi Andrew, I was wondering if there was a feature or will be in the future, in the CSMIO/IP-A to do Index homing on amplifiers that do not support it?
Most of the drives/amplifiers that would be used in a retrofit with the CSMIO/IP-A would, I imagine, be of the dumb kind, in other words it would have been the control that referenced the machine and set the machine coords when the switch, then index, was seen. As the CSMIO/IP-A already has the encoder inputs it should be possible to do this I would imagine?
Hood
« Last Edit: October 19, 2012, 05:47:18 PM by Hood »
Re: Question for TechCNC
« Reply #1 on: October 22, 2012, 10:16:46 AM »
Hi Hood,

As encoder with INDEX is connected to CSMIO/IP-A  then homing on Index is possible without any problems. Moreover it's possible in CSMIO/IP-S too. We have pdf for it (it's for Delta drives as example). Here is the link: http://www.cs-lab.eu/en/artykul-21-CSMIOIPS_Download.html

Is that what you meant?

Andrew

Offline Dan13

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Re: Question for TechCNC
« Reply #2 on: October 22, 2012, 01:16:52 PM »
This is interesting! However, I am not sure that reducing the encoder PPR to widen the index pulse would be practical in all cases.

Dan

Offline Hood

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Re: Question for TechCNC
« Reply #3 on: October 22, 2012, 04:01:01 PM »
Ok not quite clear on the manual but here is what I think you are saying in that document.
You have the axis home switch connected to a CSMIO Input and configure it in Mach for that Axis Home switch. You then take the drives buffered encoder Index output and connect that to an Input on the CSMIO and then configure the plugin to look at that index input. The buffered Index output need divided in the drives software to widen the pulse and that is all?
So if the above is correct then what will happen is Mach instructs CSMIO to home, it moves to the switch, reverses then instead of telling Mach the switch has closed it waits until it sees the index then stops and sets Machine Coords?


If that is correct then that is exactly what I am wanting :)
Only thing is I am not sure what kind of output the Index pulse is on my drives, also as Dan has mentioned you may not be able to divide the outputs on all drives. I am not sure if the older Osai drives I am contemplating using allow that but will look.

Hood

Offline Hood

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Re: Question for TechCNC
« Reply #4 on: October 22, 2012, 04:53:12 PM »
Ok had a look at both drives I have, one is the older Osai analogue command drives and they hae an encoder output from them but no means of dividing it, also I think they are just unbuffered outputs and thus will be line driver as that is what the encoder is. So seems that will not be any use on both counts?
The newer drives can have both unbuffered adn buffered encoder output signals and the buffered can be divided so that is fine but the problem is they to are line driver outputs so looks like they would not work either?

If that is the case is there another way this can be done?

Hood

Offline Dan13

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Re: Question for TechCNC
« Reply #5 on: October 23, 2012, 02:00:58 AM »
Hood,

What do you mean when you say the outputs are line driver? Could you not just use the Z (omitting the Z-)?

Dan

Offline Hood

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Re: Question for TechCNC
« Reply #6 on: October 23, 2012, 03:03:33 AM »
Yes Dan but from that Document I understood the Z output needed to be open collector, maybe I am wrong?
Hood

Offline Dan13

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Re: Question for TechCNC
« Reply #7 on: October 23, 2012, 03:40:01 AM »
Yes, I find the document a bit confusing. They are saying "line driver" and "open collector" output in the same line. I think they were meaning something else. The output spec they provide on the next line is a misleading again - why would they provide the drive's output spec? Would rather expect the CSMIO input spec instead (if anything).

Anyway, I believe it shouldn't matter if the output is open collector as it's only a matter of a pull-up resistor.

Dan

Offline Hood

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Re: Question for TechCNC
« Reply #8 on: October 23, 2012, 10:06:04 AM »
Dan
 I think what they are meaning is the encoder is a line driver but the buffered output from that particular drive is an open collector output.
On one of my drives I think the encoder outputs from the drive are not conditioned in any way and are just a direct pass through from the encoder and thus will be a line driver. On the other drive I have the choice of unbuffered or buffered but I think both of these will also be line driver outputs.
I am not sure how they would fare being connected to a CSMIO input as I think it is expecting somewhere in the region of 24v  but possibly it would work? Sadly I am not great at electronics so I am not sure, hopefully Andrew can clear things up a bit.

 Andrew,
  you said the pulse needs to be widened by dividing the Index output, how much time is needed? If a drive was not capable of dividing the encoder outputs would reducing the homing speed have the desired effect? If that is the case then it may even be possible for that to be done in the plugin, ie home at a normal rate but have the back off from the switch at a much lower rate?
Hood
Re: Question for TechCNC
« Reply #9 on: October 24, 2012, 06:11:52 AM »
We have corrected the document. Thank you for your vigilance :)