[?]: Pulse reading temeperature of pt 100 ?

dorofteius · Post by **dorofteius** » Mon May 04, 2009 8:41 am

I have a cpu 224 ac/dc/rly and a temperature to frequency converter 0-265 hz.
Anibody can explayn how to read the temeperature of pt 100?

THANKS

dorofteius · Post by **dorofteius** » Mon May 04, 2009 11:17 am

ok. I managed to read-it, but just need to know how to scale the range. The scale is aproximatively 3 times bigger.

venix · Post by **venix** » Mon May 04, 2009 8:22 pm

Hello!

I need to know the type of the converter.

Best regards!
Venix

dorofteius · Post by **dorofteius** » Tue May 05, 2009 9:14 pm

soclair electronic IR 170f-c
it reads pt 100 from -20 to 100 degrees celsius
on a frequency scale from 10 to 265 hz.
Now it reads a number from 12 ( at 24 degrees) to 40 (at 100 degrees).

venix · Post by **venix** » Wed May 06, 2009 5:14 am

Hello!

You need a calibrator device.Look at Adjustment of Measurement Range and Zero Point (Offset) in the following link.Your converter is not calibrated.

http://plcforum.uz.ua//A ... verter.pdf

If you don't need precise measurement then for 1 degree Celsius you have a value of 2 ... 2.5(Rule of 3 - Regula de 3 simpla

)

Best regards!
Venix

dorofteius · Post by **dorofteius** » Wed May 06, 2009 7:40 am

Already did-it whith the rule of thre

.
The problem is that it goes whith an error.
At 40 I have 100 degrees, and at 11 it goes at 25.
And I still need 1 degree resolution because it is nicer

,
not that I realy need-it.
And btw, the rapid share link is not working, and i have already readed the datasheet of the converter, and this model can't be calibrated.
Whith the switces You can just cange the input tipe (tested by me )

Thanx for your help. ( din ce oras esti? ).

venix · Post by **venix** » Wed May 06, 2009 12:13 pm

Try again the link!

In PLC for 1 dregree Celsius you must have 276 in digital.

Maybe the range of the PT100 is different.
Did you connect right the transducer?

Best regards!
Venix

venix · Post by **venix** » Wed May 06, 2009 5:55 pm

Hello!

You can use a potentiometer connected in series with PT100 to increase the scale.You set the potentiometer for 100 degree Celsius to have 265Hz.The potentiometer must be linear with a value of 100 ohms(as far precise as possible).When you got it you can measure the resistance of the potentiometer and change with a/some resistors at the same resistance.

The potentiometer and the resistors are temperature dependant so try to put in an constant temperature(away from the transducer).

Hope this will help!

Best regards!
Venix