SIMPLE : Converting the Temperature Sensor value to real value?

im using DVP-04pts and here is the download link to see its output:

http://www.delta.com.tw/product/em/control/plc/download/manual/DVP04PT-S_I_MUL_20090928.pdf

im reading the current value in celisius and that is 343 .. i assumed i have to divide by 10 but still the temperature in my room is sure not that high?

i couldnt understand how to read it from the manual ! heeelp

Questions:

1. Are you using the correct type of RTD platinum 3-wire sensor?
2. Is your cable a shielded wire, with the PLC end properly grounded to the FG terminal?
3. Do you have an external 24 volt DC power supply, at lest 2 watts or more?
4. Are you taking your reading from memory address H406A, H406B, or H406C? These are the Average 0.1 Degrees C Temperature Inputs for Channel 1, 2, and 3 (where H4070, H4071, H4072 are the average temperatures in 0.1 Degrees F).
5. Are there any error codes stored at memory address CR#30?

I'm reading the current value in celisius and that is 343 .. I assumed [that] I have to divide by 10.

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Yes, the output is in 0.1 degrees C, so 343 would be 34.3 C (about 93 F). That is the outdoor ambient temperature here in Alabama right now.

Your accuracy is 1% of full scale (600 C), so that would be a 6 degree error. Is your room temperature 28 degrees? That would be within the 6-degree accuracy range.

This module does not have isolated channels, so if there are other inputs, then they could interfere with your reading on this channel.

This is a very poor Instruction Sheet. Apparently it was translated from some other language.

yes to all the questions.
i tried to make it colder near the sensor and the temperature dropped to 17.
too bad i dont have a thermometer to really check the temperature in my room. ill settle for the 34 for now.

EDIT: just saw the fourth question, im taking the current temperature in celisius on channel 1.

yes this 6 degrees difference is probably it !

Thank you !

EDIT: just saw the fourth question, im taking the current temperature in celisius on channel 1.

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Are you then using the "average" temperature in memeory address H406A (Control Register #6), not the instantaneous temperature reading in memory address H4076 (Control Register #18) ?

If you are using the average, what number do you have set in memory address H4066 (CR#2, which controls How Many readings are used to compute the average)? The default value is 10. You could increase that number up to 20 to get a more accurate (but slower-to-change) reading.

yes this 6 degrees difference is probably it !

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You could try measuring a cup of ice (0 degrees), and then boiling water (100 degrees), to find if your temperature reading is ALWAYS off by +6 degrees. If so, then you can set up a scaling equation in your PLC to subtract an Offset factor from the input, and use the new number as your actual temperature.

no, the current temperature in celisius is read from H4076, is there a way to make that more accurate?

Yes, use the average temperature in CR#6 (many readings mathematically averaged over some time period). This will filter out spikes and signal noise from the true temperature.

You should protect your sensor cable, move it as far as possible from any AC wires, make sure it has a shield, and ground the shield at the PLC.

Also like I said before, if your temperature reading is off consistently by a set amount over a wide range, you can recalculate the temperature based on an Offset Correction Factor.