LOGO to monitor air quality

Hi guys,

i hope you can help me out, because I can't find the information here on my own.

I want to use Logo to monitor air quality in a room where we produce toxic gasses and use it to switch on visible/audible alarms and automatic purge gasses

Several gas sensors are hooked up to control unit. The control unit can be read out by modbus.

FIrst Logo needs to determine the range of the detector from the modbus register

Then check the read out of the detector in percentages of max range and calculate the actual level

And finally check the actual level against a threshold and switch on the alarms and purge if the level is over the threshold.

Can this be done with LOGO and how or do I need a different PLC for this?

Any input would be appreciated.

Hello,

Yes you can communicate via Modbus TCPIP 

see the attached manual 

Thanks Mazenjer,

any idea who to program the first bit? The determination of the range?

I think I know who to read the modbus register, but to translate that value into the correct range still puzzels me. I have no idea what function to use.

The rest is pretty straight forward.

Thanks for any input.

Regards, Quibusari

Hi iox65,

I have the manual for the control unit of the detectors (2 in total). M07211-Vortex-Manual-Iss-8-Jan-15.pdf (crowcon.com)  Can't upload because it's too big, even zipped

I can't connect them straight to the LOGO or I will run out of Analog inputs, which I need for pressure transmitters. I also included the modbus register overview.

For me the main problem will be how to use the input for range to something I can use.

I think I need the range input (say modbus register nr 123 - value 14, so range 0-20) to determine the maximum of the detector (in this case 20) and use that in combination with the detector level (say modbus register 3000 - value 500)

The actual detector readout in this case will be 20*(500/1000) = 10, which has to be lower than my threshold or the alarm will be triggered

But I don't know how to program the first bit.

Thanks for the help.

Regards, Quibusari

That did help indeed. I'll be able to solve it now

Thanks a lot for the help ixo65, highly appreciated

Regards, Quibusari