PWM Signal from IR Thermocouple to trigger PLC Input

Hey All,

Looking to set up a no-contact thermocouple to a piece of testing equipment that can basically just switch a NC input that shuts off the whole machine when a certain temp is reached, then restarts it once the part is cooled to an acceptable level.

Looking at a IR thermocouple from Melexis (MLX90614 family) for no other reason than it is cheap. My concern is with how this sensor will actually talk to the PLC (Idec FC5A_D16RK1).

If I use the PWM signal from the thermocouple will it be possible to use some simple math functions within my logic to turn this thing off say at 80*C or whatever we decide is needed?

Basically just need this thermocouple to operate as a relay for the input but once again, not sure if that signal will talk to my PLC. Or if anyone else has used a thermocouple in a similar manner which one worked well for you?

Thanks in advance for any advice,

Cole

Link to Thermo
https://www.sparkfun.com/datasheets/Sensors/Temperature/SEN-09570-datasheet-3901090614M005.pdf

you can use the SM bus (it is 5 volt, so you will need a converter to make it 24 volt. The PWM output is too fast or use a converter (some resistors and a cap) to make it analog 5 volt.
a simpler one use an arduino for this (sparkfun is full of it). you can use a few relais outputs of the arduino to give a limited signal to the PLC.

Omron have temperatprotection relays that go off at a set temperature - VFC output. Have a look at model number K8AB-TH1. I use them and they just work. They work on either RTD or thermocouple.