sensor to relay circuit and wiring

[benjiAU]

Hi everyone this is my first post.

Im more a mechanical guy so be kind

I would like to see if someone could tell what I need to setup a circuit from a CO2 sensor RS5600 https://www.electro-tech-online.com/custompdfs/2010/03/RS5600.pdf to operate a 24v fan relay.

I would like to be able to adjust the ppm activation point. Im lost and need help. :/


any help on wiring and components would be great.

thanks
benj

 

[Hero999]

You need an amplifier with a very high input impedance >100GΩ with a gain of something like 100 to convert the 30mV to 50mV output to 3V to 5V.

The CA3130 configured as a non-inverting amplifier should do.
https://www.electro-tech-online.com/custompdfs/2010/03/fn817.pdf

Unfortunately it has a maximum supply voltage of 16V so it needs a regulator. The sensor you've linked to requires a 6V power supply. An LM317 could be used to power both the sensor and the op-amp.

Do you know the resistance of the relay coil or how much current it needs?

If it's >500Ω or uses less than 50mA the LM311 comparator could be used to drive the relay directly, if not, you need an additional booster transistor.

 

[benjiAU]

Thankyou for responding.

From what I understand (assume) i will need a 12/24v relay working at 300Ω?

would that make sense?

Forgive me.. I really am a learn as I go person (i try my best to learn as quick as possible as to not annoy anyone to much). Whatever information i will take to my local tech shop and get them to help decipher it for me.

 

[Hero999]

A 300R coil will need a booster transistor.

Use a non-inverting amplfier.
**broken link removed**
Operational amplifier - Wikipedia, the free encyclopedia

Set the LM317 to 6V
**broken link removed**
R1 = 180R
R2 = 680R

The comparator design will depend on the threshold.