Also make sure your input voltage to the instrumentation amplifier. Is inside the common mode given for that instrumentation amplifier

 

......because you can do the data sheet search as well as I can, ....

ha... this is what I always thought, but it proved to be wrong, and to be the source of all problems.

Thanks for the advice. Following the recommendation of another fellow here I had the Microchip MCP6XXX family in mind. But now I will also consider the instrumentation amplifiers.

 

Edited to add: Also, the load on the output limits the output voltage. What is it loaded with? For max output, the load should be no more than 10K Ohms.

Bob

In the mean time there is no load connected to the output. Only my multimeter.

Thanks