I have a machine that uses simatic S5 , to one digital input 24Vdc connected in series a thermocouple

which i dont know the details off this element

When the motor is cold i measure 24 Vdc in the digital input i mentioned

as the motor works and get hot the voltage redused (measure 10VDC), and i have from my machine the error overtemperature motor

Can someone tell me what kind off thermocouple used ?

Hello,

if protection is connected to digital input it is not  a thermocoupe (thermocouple is analog device) but a thermal switch.

here some basics.

Do you want to know exactly the code of your thermal switch???  try to ask here 

Best Regards.

Hi,

Nikolaosst77 add more detail of the s5, of the  module and of the sensor to help you.