connecting to existing sensor

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seracing
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connecting to existing sensor

Postby seracing » Fri Dec 28, 2012 3:17 pm

I want to connect my 1011 to an machine to get a count for production efficiency monitoring. The machine currently has a 24vdc inductive sensor. I would like to put a relay in line so my 1011 is isolated from the machine. Any suggestions on a cheap relay that would work?

thanks,

Iowegan
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Re: connecting to existing sensor

Postby Iowegan » Fri Jan 04, 2013 7:55 pm

Yeah, you can find 24vdc relays on eBay, pretty reasonably priced.

Since your suggesting a SPST, or, SPDT relay, you can get one for less thana couple bucks.

For example :arrow:
http://www.ebay.com/itm/Relay-24V-DC-SP ... m2325104c4

seracing
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Re: connecting to existing sensor

Postby seracing » Fri Jan 11, 2013 5:17 pm

Iowegen,
Thanks for the suggestion. Been a while since I have had a chance to get back to the forum.

I have a couple more questions that hopefully can be answered. I can use a SPDT relay, connecting the NO side to my plc and the NC side to my phidget. When the sensor goes high, the relay will close, completing the orginal sensor circuit to the plc input. I then monitor the state change with my phidget code.
Would this work?

Also can the 1011 handle the 24vdc input?

Thanks,

Maybe I am overthinking this! Could I just run a wire to the terminal strip of the 24vdc signal and connect that to the positive input, run a wire to the termial strip common for the negative input. Then connect the the output to the phidget digital input. This should isolate my computer from the machine?

erik
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Re: connecting to existing sensor

Postby erik » Mon Jan 14, 2013 10:07 am

Check out the Digital Input Primer, specifically the "Monitoring the Position of a Relay" section (which I think you are describing).

seracing wrote:Maybe I am overthinking this! Could I just run a wire to the terminal strip of the 24vdc signal and connect that to the positive input, run a wire to the termial strip common for the negative input. Then connect the the output to the phidget digital input. This should isolate my computer from the machine?

If I understand the set-up correctly, you are describing the section "Using a Capacitive or Inductive Proximity Switch" section from the Primer, but without the ground connection to the 1011. The digital input would not reliably detect the state changes without the connection between the ground of the sensor to the ground of the 1011. This would not be isolated.

seracing
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Re: connecting to existing sensor

Postby seracing » Wed Jan 16, 2013 12:03 pm

Erik,
Thanks for the response. Using Iowegan suggestion, I would be using the signal wire from the sensor to pull in the coil of a 24vdc sensor. Using the sensor wire ground along with it. Then I would connect my 1011 to the relay. The relay would be a "dry contact". Would this work?

thanks,

erik
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Re: connecting to existing sensor

Postby erik » Thu Jan 17, 2013 9:15 am

Yes, this would work.

seracing
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Re: connecting to existing sensor

Postby seracing » Thu Jan 17, 2013 3:37 pm

thanks,


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