The Industrial Raspberry Pi Forum

Hello everybody,

i would like to control the compressor speed of a SECOP BD50F with my RevPI AIO module. Therefore i need to connect the c and t pin of the compressor with my aio.
How could i set a variable resistance from 0 to 1500 Ohm?

Should i connect the c/t pin to the +I and ground pin of my aio and control the compressor speed by setting 5mA --> R=0 --> speed=2000rpm and by setting 2mA --> R=1523Ohm --> speed = 3500rpm according to the datasheet?
Or should i adjust the resistance by setting a ca. 3 V signal --> 2000rpm an 0V signal --> 3500rpm?
Or should i use a digital poti?

Thanks for your reply.

Kind regards
Simon

Datasheet
https://assets.danfoss.com/documents/59 ... 000101.pdf

Dear Simon,

could you pls. so kind and provide us with a circuit diagram?

Thank you very much in advance,
BR, Julian, Kunbus Sales

If the switch is open --> speed is zero
if the switch is closed and resistance is zero --> speed 2000rpm
if the switch is closed and resistance is 1523 Ohm--> speed 3500rpm

Could i connect a AO to C and T instead of the switch-resistance circuit to adjust the resistance? Or do i have to use a digital poti and a switch?

Hello Simon,
yes you can connect the AIO to C and T instead of the switch-resistance circuit to adjust the resistance.
As you know U = R * I => R = U / I . So you can replace the resistance with the Voltage and the Current. In the photos bellow you can see how to connect the AIO Pins with the Thermostat.
Salma.