[?]: 4 Mass flow meter connect to only one input

[pinkerton]

Hello,
Does anyone ever connect 4 sets of mass flow meters into the same analog input ( Point I/O). My project have to supply material to 4 separated tanks but I have only one analog input. Could I connect all flow meters into single input and build the switching for selection. I don't want to creat 3 new subroutine ladder because its has difficult to do that.

Anyone please suggest me!!!

[Homeroid_BL]

It is NOT good to connect more then ONE analogue signal to analogue input. Buy AI card and expand your system.

You can do what you want, using multiplexing (four 2PDT relays) before AI, and call paramater set 'n' when signal 'n' is selected. But, there are transition processes, so you can not get analogue valuse immidiately. But, this is NOT good engineer's approach.

[joker12]

I agree with pinkerton. Do Not connect 4 mass flow meters to one analog input. How are you going to determine what value is coming from which mass flow. Use one analog input for each mass flow. You just have to duplicate the logic, no big deal.

Some Mass Flow meters can give 4-20 ma and pulse outputs i.e. Andress-Hauser

For pulse outputs you can use the Spectrum 1746sc-CTR4/8 card for SLC500. Google to get more info. Easy to program.

That leaves the 4-20ma for density measurement.

I'm getting ahead of myself.

Good Luck