3K NTC Thermistor

[wbarkley]

Hello,

I'm having trouble getting a value from a thermistor. What is a good method for connecting a 3k ohm thermistor to  a Vision PLC? And what would be the hardware configuration for that input? as well as the jumpers.

Thanks.

[DanT]

Hi;

Unitronics PLC's do not support  Thermistors.

Unitronics PLC's with temperature inputs support   Thermocouples or  100ohm RTD   or 1 kohm RTD ( IO Module)

You can refer to the installation sheet that came with the PLC or look on line at Unitronicsplc.com , Technical support and tech documents

for the model you have.

 

You can look up on the internet  for a Thermistor interface to a 0-10V  analog input. 

The calibaration will be up to you to figure out - do the math.

Note that analog inputs on models without temperature input are 10 bit ( 0-1023)

 and on models with Temperature inputs the analog resolution is 14 bit ( 0-16767)

DanT

 

[Flex727]

3 hours ago, DanT said:

and on models with Temperature inputs the analog resolution is 14 bit ( 0-16767)

or 12-bit in Fast Mode.

[wbarkley]

Thanks for the info!

Looks like I'll be changing the sensor over to PT100's to make life easier.

[Ausman]

I know this is a bit late, but the original question has been filtering through the brain cells and finally found the link that was wandering around in my head.

A long long time ago, in a land far far away before the plethora of modern stuff was readily available, I used a modified version of the following to give me ambient temperature readings from a simple waterproof sensor.  The 335s were cascaded as shown in as small a space as possible, and were then covered in double wall (hot melt inner) heatshrink.  This resulted in usable readings on the 0-10v scale that were linear.  The working range wasn't much, but it was good enough for what was needed and actually worked surprisingly well.  Wasn't that fiddly to build and thus easily replaced, but never needed to be.   Was mounted externally in a sun-shielded forced airflow location.

cheers, Aus