Hi,

I plan to manipulate the outputs of the thermocouples TypeK with a small 
circuitry and a simple potentiometer to adjust that output.

As the thermocouple itself is a voltage source, I ask myself if I could 
add and subtract a small voltage in order to manipulate the signal to 
get the PLC to read a different temperature, ajustable with a 
potentiometer. A simple voltage divider may be too baremetal, as the 
voltages roam around 25mV per Deg C. I only need temperatures >0°C

any suggestions how this could be done?

and please, in the German speaking boards, I would receive posts with 
"go and study electronics" etc... yea, if I could do so, I wouldn't need 
to ask and it is zero help... So I hope ther more international website 
here is more understanding :)

Many thanks!