Hi Vasile

> Joe,
> 
> PT100 does not need shielded cable even in automotive application

Perhaps you missed the diagram that Mike and I have been referring to

http://home.clear.net.nz/pages/joecolquitt/0-10mA_remote_lm335.gif

The PT100 is being used as the important sensor, the much cheaper
LM335s are for more general temperature indicators

The possible problem is op-amp instability

> (that's why with 0-10mA you will never be able to know if the problem
> is with your RTD or with your circuit as long the output value for a
> given temperature will be near 0mA).

That's true. The 0mA of a 4-20mA system would be used as error or
fault detection. For this little short-lived project I could go with either
0-10mA, and accept the risk, or 2-10mA

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