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probe interface with kanalog

Posted: Sun Mar 01, 2020 7:09 am
by boss4
Hi,

I recently acquired an old renishaw touch probe. It has a builtin battery. I could eliminate the battery and go to any kanalog input but I am considering leaving the battery intact and bringing the input to a opto in. Its missing the original transmitter / receiver portion of the probe so its possible there was more going on originally but as it is now it is just a switch in series with a battery.

Would this be a bad idea in terms of latency for the probe switching if using an opto input? If I do this are there any other considerations I should be aware of?

Thanks

Re: probe interface with kanalog

Posted: Sun Mar 01, 2020 5:15 pm
by TomKerekes
Hi boss4,
I recently acquired an old renishaw touch probe. It has a builtin battery. I could eliminate the battery and go to any kanalog input but I am considering leaving the battery intact and bringing the input to a opto in. Its missing the original transmitter / receiver portion of the probe so its possible there was more going on originally but as it is now it is just a switch in series with a battery.
If the battery is 5V or higher I would expect that to work connected to a Kanalog Opto Input.


Would this be a bad idea in terms of latency for the probe switching if using an opto input? If I do this are there any other considerations I should be aware of?
The Kanalog Opto Inputs are pretty fast (few microseconds). Since the probe signal is sampled in software that would be the limiting factor (180us sample times). I don't see any issue.

HTH

Re: probe interface with kanalog

Posted: Sun Mar 01, 2020 5:25 pm
by boss4
Thanks Tom I think the battery is an A23 (12v). It would be wired as normally closed.

Re: probe interface with kanalog

Posted: Sun Mar 01, 2020 5:34 pm
by TomKerekes
Hi boss4,

That should work. However Kanalog Opto Inputs consume ~1ma of current at 12V. An A23 battery is supposed to have ~55mAh of capacity. So with it normally closed the battery would need to be replaced every 2 days whether the machine was in use or not unless it would be disconnected when not in use.