Voltage to Resistance???

I have a PLC that is around three years old and would like to add a few more sensors. I have no more comm ports but spare analog inputs. I would like to try to do this with a couple of wireless transceivers. It will be very difficult to get any cabling to each sensor.

I would like to have a PIC read the sensor such as pressure, temp then wireless transmit its value to the remote receiver. The receiver will need to use a table or math conversion to reproduce the resistance of the sensor for interfacing with the analog inputs on my PLC.

I have been thinking about using multiple digital pots to covert the value back to resistance but it will take a couple pots to reproduce the curve for the sensor.

Are there any voltage to resistance converters that might work for this?

Any help would be greatly appreciated,

Scott

Most commerical PLC's (eg Trend) will accept a 0-10v ADC input. Pretty simple to PWM a 10-bit resolution value to simulate your Sensors range. Search the forum for "0-10v" for a voltage doubler circuit.