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Which FP module can read resistances?

Hello community,

 

I have a digital encoder or index for a gas meter that provides electrical resistance 10x every revolution. I'm not very savvy on how the electronics work exactly, but I understand that it's a very common way to measure this type of thing.

 

My question is what Field Point module is capable of counting these resistance measurements and how to set up the counter if need be. I do have LV2014SP

 

Thanks

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Message 1 of 11
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It seems strange that you are trying to read in a resistance on a counter task. An encoder usually outputs a voltage. What is the encoder that you are using?

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Message 2 of 11
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Message 3 of 11
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It doesn't look like NI sells any FieldPoint devices anymore. What are you trying to do? I'm sure there's a device currently being sold that can do that.

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Message 4 of 11
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well I already have FP quad510,DO400,AI110s hopefully it's either the quad510 or the DO400.

 

All I'm trying to do is use a digital counter to count pulses coming from the index.

 

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Message 5 of 11
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I think everything is wired up to the Quad510 properly, but still not getting any readings.

Could it be because the time stamp is not updating in MAX?

 

timestampMAX.PNG

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Message 6 of 11
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The Quad 510 should be great for reading an encoder.

 

Have you checked the manuals for the encoder and Quad 510 to be sure everything is connected and configured correctly? 

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Message 7 of 11
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Yes, unless I'm missing something.

+wire from encoder into terminal 15 for the Quad

-wire from encoder into terminal 31 for the Quad

ground from encoder into COM terminal on Quad

 

So index 3 on the Quad should read a boolean value when resistance is detected, correct?

Sometimes I will get a boolean reading on one of the indexes, but not on index 3 like it should be. Once it hits a reading "1" it gets stuck, even after unplugging the wires from the encoder and resetting the FP bank via MAX.

Also, sometimes I will get a random bogus reading on one of the "position" channels like 4325818415

QuadTerminalassignments.PNG

 

But the thing that's still bugging me is that the "Time Stamp" in max is not updating with the PC time unless I start/stop the task.

timestampMAX.PNG

 

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Message 8 of 11
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Your device output is a simple switch closure, while the Quad 510 expects a TTL level (~0 logic low, ~5V logic high).

You will need to wire a 5V supply in series with the output of your device and use the single ended input configuration on the 510.

EDIT: I see that the 510 has a 5V output you can use.

 

If you get that working, you may still have reading errors since mechanical switch contacts tend to 'bounce' closed and open several times before making a stable contact closure.

 

-AK2DM

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"It’s the questions that drive us.”
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Message 9 of 11
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I've heard there are some ways to reduce bounce in labview. Like taking the top and the bottom of the reading and cutting it into pieces and track the time between highs and lows.

 

Do you know of any examples of something like this?

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Message 10 of 11
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