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RTD temperature fluctuation


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Hi, I am new to almost every thing here. It just happen that my equipment which uses Unitronics "V230" PLC and "V200-18-E3XB" IO Module is down due to 5~10degC temperature fluctuation from a RTD sensor. I am seeking for advices from the experts here. Below drafted is the configuration:

RTD sensor ported into a cooling water pipe --> Analog IN terminal "AN1" of E3XB --> V230

As of today, we have replaced the RTD sensor and V230, but it didn't fix the fluctuation. Our next plan is to replace the V200-18-E3XB IO Module, but we are not sure if there's any set up or configuration need to be done prior to install this module. I have been searching for this info in the web for hours, but found nothing. Thanks

post-1608-041142300 1300416881_thumb.jpg

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Hi, I am new to almost every thing here. It just happen that my equipment which uses Unitronics "V230" PLC and "V200-18-E3XB" IO Module is down due to 5~10degC temperature fluctuation from a RTD sensor. I am seeking for advices from the experts here. Below drafted is the configuration:

RTD sensor ported into a cooling water pipe --> Analog IN terminal "AN1" of E3XB --> V230

As of today, we have replaced the RTD sensor and V230, but it didn't fix the fluctuation. Our next plan is to replace the V200-18-E3XB IO Module, but we are not sure if there's any set up or configuration need to be done prior to install this module. I have been searching for this info in the web for hours, but found nothing. Thanks

Ok. Found out that there are 16 jumpers to set. But other than the jumpers, is there any thing else need to be set before and after new IO Module installation?

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Ok. Found out that there are 16 jumpers to set. But other than the jumpers, is there any thing else need to be set before and after new IO Module installation?

Hi,

Some questions:

Are you using the RTD just to read temp, or is the V230 actually controlling the water temp somehow?

If the temp is fluctuating, has it been considered that the fluctuation might actually be in the the temp of the water in the pipe and that the sensor is in fact working just fine?

Is the cooling pipe such that you are guaranteed the RTD is always completely submersed in the water? (ie, possibly cavitatation, possibly air pockets if horizontal and RTD enters from the top.)

What is the frequency of the "flucutations"? Describe them a bit more? Is it sinusoidal? sporadic? Does it occur maybe when a pump motor kicks in?

Are you using a shielded RTD? Have you kept it isolated from high voltages?

Is the V230 mounted on an enclosure and is the temperature inside this enclosure stable?

Is the tip of the RTD in direct contact with the water, or does is just sit in a T/C type well?

All the documentation of the module is available right on Unitronics Website. Not sure why you are having such a hard time finding it. Yes, you definitely want to make sure you have all the settings and jumpers set properly.

Make sure the operands you tied to the analog input are not being used somewhere else in the program.

Hopefully one of these might be the cure.

D

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Some questions in addition ot Damian's (which are very important!):

How many wires has the RTD sensor?

How exactly is connected?

What is the cable length from sensor to the controller?

If you handle the sensor in the air - is the reading stable?

Can you connect the sensor direct to controller - with relativelly short cable (1-2 meters), put the sensor in a cup of water and see if the reading is still unstable?

What is S/N number of V200-18-E3XB?

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Some questions in addition ot Damian's (which are very important!):

How many wires has the RTD sensor?

How exactly is connected?

What is the cable length from sensor to the controller?

If you handle the sensor in the air - is the reading stable?

Can you connect the sensor direct to controller - with relativelly short cable (1-2 meters), put the sensor in a cup of water and see if the reading is still unstable?

What is S/N number of V200-18-E3XB?

Hi Emil,

His first post actually has his wiring Diagram. It is a three wire RTD. It does appear to be wired correctly (assuming they followed the print).

Good Idea with the glass of water!

Damian

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  • 3 weeks later...
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I had a very important fluctuation measuring a temperature because the cable of the RTD was by the same canal that the cables of fluorescent lights. I noticed that swithing off the lights. Some electrician don't know about RFI.

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