adccommunitymod (AutomationDirect) asked a question.
Created Date: August 14,2014
Created By: wguasti
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I have the following configuration: PLC click "CO-01DR-D " after "CO-08TR " after "CO-08TR " after "CO-04RTD " and finally another "CO-04RTD ". Use sensor PT100 in my application. The 8 channels available, I'm using 7. All contactors and coils have suppressor (RC) noise in parallel. The cables of the PT-100 sensors are not together with the power. Only in some places inside the electric panel. Are shielded, and grounded individual cables. When no drive is active, temperature viewed through the program (C-More Micro) and correct and stable. When any drive is active, all temperatures have significant variations. For example: stopped Equipment: Temperature varies 30,0C to 29,9C to 30,0C after 30,1C. That and normal. Now, with any active drive machine: Temperature varies 30,0C to 29,2C then to 29,7C then to 29.9, then to 30,2C in the same time interval of the previous example. I understand that this is some noise, or lack of a filter on the analog input card. Is there any feature in the software to add filter to the analog input card "CO-04RTD "? To test, I removed the cable from the PT-100 sensor was connected to the card "CO-04RTD " and I connected it to an external temperature controller, in order to verify if the variation in temperature would remain. The result was good, the temperature does not vary in any situation. Soon understand that the problem is in the card "CO-04RTD ". Would appreciate a solution to my problem. Thank you
Created Date: August 14,2014
Created by: plcnut
You may need to put a powerline filter on the PLC power supply.
Created Date: August 14,2014
Created by: Szarman
±1ºC repeatability is the specification after 30 minute warm up. Your module seems to be working correctly with the temperature values you listed, or at least is within the specification of the module.
Created Date: August 14,2014
Created by: wguasti
my friends, it's not normal for me, variations about 1 degree, it's so much.
Created Date: August 14,2014
Created by: Bob S BN
Info in this thread...
http://forum.automationdirect.com/showthread.php?t=12257
the mathmatical filtering may help stabilize your readings, at the expense of slower updates.
Created Date: August 14,2014
Created by: Tinker
my friends, it's not normal for me, variations about 1 degree, it's so much.
Perhaps so, but one needs to consider that the CLICK is "so cheap ".
If, for example one wanted to switch to the Do-More, or P3000 one could get RTD modules with better specifications. Actually in the case of the P3000, while a P3-08RTD costs somewhat more than twice as much as a C0-04RTD, it has 8 channels so price per channel is not a lot more (though the P300 CPU and baseplate will be a lot more money than a CLICK). A F2-04RTD for use with a Do-More is just about twice the price of a C0-04RTD and it also has four channels so the price per channel approximately doubles.
I imagine that the Do-More and P3000 also have built in filtering routines, with a CLICK one would have to write a filter one's self (not that that is too hard top do. Not to toot my own horn, but I did but some effort into my post in the thread Bob linked to (on the second page))
Created Date: August 15,2014
Created by: AlbertL
An important question is: what are the requirements for your application? Or, how much do the variations you 're seeing impair the functioning of your system/process?
Created Date: August 15,2014
Created by: AlbertL
You may need to put a powerline filter on the PLC power supply.
Excellent suggestion, especially since (per the spec sheet) the C0-04RTD does not have isolation between the field and logic sides.
Created Date: August 14,2014
Created by: wguasti
I have the following configuration:
PLC click "CO-01DR-D " after "CO-08TR " after "CO-08TR " after "CO-04RTD " and finally another "CO-04RTD ".
Use sensor PT100 in my application. The 8 channels available, I'm using 7.
All contactors and coils have suppressor (RC) noise in parallel.
The cables of the PT-100 sensors are not together with the power.
Only in some places inside the electric panel.
Are shielded, and grounded individual cables.
When no drive is active, temperature viewed through the program (C-More Micro) and correct and stable.
When any drive is active, all temperatures have significant variations.
For example: stopped Equipment: Temperature varies 30,0C to 29,9C to 30,0C after 30,1C. That and normal.
Now, with any active drive machine: Temperature varies 30,0C to 29,2C then to 29,7C then to 29.9, then to 30,2C in the same time interval of the previous example.
I understand that this is some noise, or lack of a filter on the analog input card.
Is there any feature in the software to add filter to the analog input card "CO-04RTD "?
To test, I removed the cable from the PT-100 sensor was connected to the card "CO-04RTD " and I connected it to an external temperature controller, in order to verify if the variation in temperature would remain. The result was good, the temperature does not vary in any situation.
Soon understand that the problem is in the card "CO-04RTD ".
Would appreciate a solution to my problem.
Thank you