Eurotherm Drive with PT100 Input

You need pt100 with 0 to 10v output.

I don't know much about a Eurotherm drive, but if I were controlling motor speed based on an input temperature, there would typically be a transmitter connected to the actual Pt100 (or Pt1000) sensor, that would convert raw signal into a temperature value, then the temperature value would be transmitted out on a 4-20mA (MOSBUS RTU) line to a PLC, and the PLC would in turn control the VFD that turns up or down the motor speed. If, however, you want to avoid the PLC, check with the OEM of the motor controller (VFD?), and see if there is an input for a direct temperature sensor, if they need a 4-20 mA input, etc.

If, ALL you want is increase/decrease the speed of the motor, without setting a target temperature to maintain, then:

1) You need a signal conditioner to convert the PT100 resistance value, to a 0 to 10V signal, covering the temperature range you expect to deal with.

2) all VFD drives will have an Analogue input, 0 to 10V, where the signal can be directed to.

3) You need to configure the VFD (Inverter), to get the frequency source from the Analogue input. Also, the maximum and minimum frequencies your motor should keep within range (very important here).

IF you want to achieve a target temperature to maintain, then the problem will be different, as you will need to use a PID input, if the inverter you are using is equipped with one). You still need the signal conditioner as above. The setting of this type of control will need to be done by an experienced person or at least you need to read a lot of info for the particular equipment you have. Also, you will need to experiment your settings safely, and go through a learning curve as you will fail many times before you get it right!

Is that the AC drive or DC drive? What model?

Closed loop speed control with tachometer gives the tightest speed control.

This control loop is controlling temperature not speed. temperature control usually has a fairly high gain with very little integral. The control system does not care what the motor speed is. Feedback will be temperature not speed.

I miss read the OP.

You are correct, it appears he is trying t6o regulate temperature.