This application note explains how to obtain a 0 to 10V analog output voltage using the EMANT300. This circuit is used in a proportional valve application. The proportional valve control flow rates from 1.4 to 5m3/h. The variable opening of the cross section is changed proportional to the 0-10V input signal
The analog input range required by the proportional valve is 0 to 10V whereas the analog output of the EMANT300 USB DAQ module is a current from 0 to 1mA (see EMANT300 specs).
The following non inverting opamp circuit is used to convert the 0 to 1mA output to 0 to 10V output.
The opamp LM2904 is connected in a negative feedback configuration. V- is given by
IDAC is the current output of the EMANT300. V+ is given by
In negative feedback, you can assume that V+ = V- Combining both equations gives
Substituting the component values from the schematic into the equation, gives the following relationship