Kanalog Opto in limit switch current LED

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MadTooler
Posts: 86
Joined: Thu Nov 08, 2018 11:57 pm

Kanalog Opto in limit switch current LED

Post by MadTooler » Sat Apr 23, 2022 3:47 pm

I am upgrading my limit switches to 5 micron accurate limit switches from Metrol. They will be 24vDC and interfaced to the Kanalog opto isolated inputs on JP15. See attached PDFs for the switches.

These switches have an LED in series without any current or voltage limiting included. Metrol suggests a 2K resistor to be added in series for a 24vDC system. Something like this (my note of opto terminals in red):
LEDcurrentLimitNotes.PNG

Per the spec's for Kanalag, I noticed the opto inputs already have a 10k resistor in series
Opto Isolated Inputs = (8) 3-24V input, internal 10KOhm series resistor
Does this mean I will not need the addition of the 2K?

Thanks.
Attachments
ls90degreestraightls.pdf
(887.92 KiB) Downloaded 13 times
GM-AB91E-CS-K001.pdf
(223.63 KiB) Downloaded 14 times

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TomKerekes
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Re: Kanalog Opto in limit switch current LED

Post by TomKerekes » Sat Apr 23, 2022 4:59 pm

Yes. Their LED may not glow or be very bright but the circuit should function. You might put like a 3K ohm resistor in parallel with the Kanalog input if you would like their LED to glow brightly.
Regards,

Tom Kerekes
Dynomotion, Inc.

MadTooler
Posts: 86
Joined: Thu Nov 08, 2018 11:57 pm

Re: Kanalog Opto in limit switch current LED

Post by MadTooler » Sat Apr 23, 2022 5:25 pm

Thanks, Tom. That was what I was thinking too. I do not really need the LED indicator. They will be hidden after assembly anyway. I would have simply ordered the non LED version if they were in stock.

Have a good weekend!

MadTooler
Posts: 86
Joined: Thu Nov 08, 2018 11:57 pm

Re: Kanalog Opto in limit switch current LED

Post by MadTooler » Tue May 24, 2022 9:11 pm

Tom,

An update on these Metrol limit switches...

The LED lights up plenty bright without adding any additional parallel resistors. The onboard series resistors on Kanalog do the trick without any extra mess!

The switches also seem well under the 5 micron repeatability for now.

Cheers!

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TomKerekes
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Re: Kanalog Opto in limit switch current LED

Post by TomKerekes » Tue May 24, 2022 11:29 pm

Good to know.
Regards,

Tom Kerekes
Dynomotion, Inc.

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