Analog inputs mixed (0-5V and 4-20mA) in k8055

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1

Hello everybody …

I’m making an expirment using pressure sensors and temperature sensors. I have the k8055 board. Temperature sensors have output 0-5V, but pressure sensors have output 4-20mA. I wouldn’t modify the hardware of my board. My questions is: Is it possible to have the in same board with different analog inputs, (0-5V) and (4-20mA), similar to the analog outputs (PWM and DAC)? (for a future version of k8055)

Could somebody tell mi what hardware I have to add to my experimet in a separate board build by myself, without modifying my k8055? If I have to modify my k8055, which is de best solution?

Thanks a lot,
Ángel.

2

To convert a 20mA current loop into a voltage, simply put 250 ohm from analog input to ground on the K8055 (= 4x1K in parallel). Make sure all analog signals that are fed into K8055 have same ground level.

3

Thanks a lot.

It’s very easy to add this resistence in parallel. I think that RV1 and RV2 should be adjusted to have 5V in the point 3 of IC1A or in the point 5 of IC1B.

Best regards,
Ángel.

4

Yes, adjust RV1 and RV2 to max position.
Remember to remove the jumper caps on SK2 and SK3.