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Unread August 23rd, 2017, 08:32 AM   #1
RMore
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Micro 820 - 2080-TC2 thermocouple filtering

What's the most effective filter to use for the thermocouple wiring on the input to the 2080-TC2 plugin module on a Micro800 based design?
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Unread August 24th, 2017, 01:03 PM   #2
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Additional information: The 2080-TC2 module is intermittently faulting a few times a day, potentially due to a solenoid switching. Most of the time the fault only results in a bad reading or two, however, on a few occasions it has crashed the program resulting in error code F0A1h). I assume that it is noise from one of the solenoids making it's way to the TC module, either thru the power supply or the unshielded TC cable, however, I am not yet able to get it to fail on the bench. Has anyone experienced faults on the TC Module and what was the ultimate fix?
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Unread August 24th, 2017, 01:16 PM   #3
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https://www.youtube.com/watch?v=8KhqIbwcOhg

http://www.mosaic-industries.com/emb...e-noise-filter


Last edited by Dirt; August 24th, 2017 at 01:19 PM.
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Unread August 24th, 2017, 02:20 PM   #4
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Dirt, Thanks for the replay. Useful information ,however I do not have control over the input circuit design for the module and Rockwell does not provide a schematic. Also, the module does not provide a ground terminal. I was able to determine that the input impedance is roughly 340K with the negative input tied to ground thru a 10K impedance.
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Unread August 24th, 2017, 03:24 PM   #5
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Set your data refresh rate to 50 Hz this will help.
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Unread August 28th, 2017, 09:36 AM   #6
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Currently my update rate is 16.7Hz I can change it to 50Hz. Can you explain what factors determine the optimum update rate?
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Unread August 28th, 2017, 12:39 PM   #7
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According to the manual 16.7 Hz refresh rate will result in an accuracy of + or - 1% (Do you really need that tight of results?)

A 50Hz refresh rate will result in a + or - 3% accuracy (This forgives a lot of noise/spikes/Etc..)

You might just try and make sure it works for your needs.
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Unread October 9th, 2019, 07:53 AM   #8
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What about ferrites?

Has anyone had any success using ferrites on thermocouple wires to reduce noise spikes getting into the inputs? What about adding a cap or MOV across the input?
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Unread October 9th, 2019, 12:25 PM   #9
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Quote:
Originally Posted by RMore View Post
Additional information: The 2080-TC2 module is intermittently faulting a few times a day, potentially due to a solenoid switching. Most of the time the fault only results in a bad reading or two, however, on a few occasions it has crashed the program resulting in error code F0A1h). I assume that it is noise from one of the solenoids making it's way to the TC module, either thru the power supply or the unshielded TC cable, however, I am not yet able to get it to fail on the bench. Has anyone experienced faults on the TC Module and what was the ultimate fix?
Surge protection on all inductive loads? Will help if this is your problem.
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