ixo65

 

sx50

tip in boiling water the A/D output voltage was 1.343 VDC.

 

The settings that you have made on the transmitter are the correct ones for type K.
The wiring is correct between the transmitter and the LOGO!

Did you measure the voltage you measured (1.343 VDC) without any load on the transmitter? Or was the LOGO! connected to the transmitter as a load?

 the logo was not connected to the transmitter.the voltage measurement was without logo!.

ixo65

As already written several times, the transmitter must output a voltage of 2.5V at 100 ° C. If it does not, either the transmitter or the thermocouple is defective.

But which of the two, I can not say.

i changed the thermocouple with another brand new K type thermocouple and i checked the output again,i got same result

thank you for your helpful guides

ixo65

Is it absolutely certain that the thermocouple is type K?

 yes.the type is labled on the thermocouple head 1xK(Ni-Cr-Ni).and i always use this type in my projects.

ixo65

Sorry, then I do not know how I can still help you.

 thank you for your time that you spent for me.

and last question

if i decided to change the transmitter,witch one of brands do you prefer to suggest to me?

1:wago

2:phoenix contact

or any brand that you suggest...

thanks you again

by using a precision multimeter you can measure thermocouple output mV.

4.096 mV for 100 degree celsius from the omega k type mv table.