JB2020 (Customer) asked a question.
Does anyone know if these flow meters work good with just plain water?
I am looking into using them for measuring the amount of water in gallons that flows into a mixing unit. The preference would be to be able to enter, for example, 36 gals and hit start, the PLC would reset the meter, open the solenoid valve. The meter would count up to that amount and signal the PLC to shut the valve. Do I have the correct valve selected for this application?
I don't think it will do it as you wish. It does appear to have a selectable pulse output when a gallon mark is met, but you would have to program it at the meter, and I am not sure the method of reset. You could use the flow rate and do the gallons from that in the PLC, might be the best way to get it depending on your accuracy requirements.
As for being good with just plain water, it would appear so long as the minimum conductivity rates are met ( and tap water is OK ), you would have no issues. Obviously if you were running DI or distilled, it would net read.
Best I can help you out, good luck and if you try it, let us know how it turns out!
That will work, your PLC will have to do the hard work, and if the amount is a variable you will need some sort of HMI to set the desired amount. The PLC needs to count pulses or integrate the analog variable and convert to your engineering unit if choice and shut the flow of water off in time to reach your target.
However, this is simply a meter, not a shut off valve like you allude to at the end of your post.
Thank you for the thoughts. I believe this meter can be set to pulse for either 0.01 or 0.1 or 1 gallon marks. Is this correct?
I plan to use a separate solenoid valve, I understand this is only a meter. My thought was to count pulses using one output on the meter and then use the other output for a reset just to reset the display on the meter itself. I realize I don't need the reset for the PLC counting or the HMI.
And, to clarify, I am not using distilled water; just tap water from the city supply line.
I believe your plan is achievable as you have spelled it out. Depending on the precision you require, it may be necessary to shut off the solenoid early to account for flow that can occur during that tiny amount of time required for the valve to close. I worked on a similar setup in a food plant using a GPI turbine meter, but these Prosense models look like a better solution at a better price.
The meter volumetric pulse totalizer is settable from 0.010 to 100,000,000 GAL. This is a setting of gallons/pulse meaning that if you have the setting set to 0.5GAL, the output will turn on (for a settable amount of time) whenever 0.5gallons have moved through the meter.
In you case (depending on accuracy, flowrates, and PLC input speed) you could set the meter to say 0.1 GAL/Pulse for totalizer. In the PLC yo would add 0.1 to the total value on every rising edge of the input. When the total=> setpoint you would turn off the output.
The meter volumetric pulse totalizer is settable from 0.010 to 100,000,000 GAL. This is a setting of gallons/pulse meaning that if you have the setting set to 0.5GAL, the output will turn on (for a settable amount of time) whenever 0.5gallons have moved through the meter.
In you case (depending on accuracy, flowrates, and PLC input speed) you could set the meter to say 0.1 GAL/Pulse for totalizer. In the PLC yo would add 0.1 to the total value on every rising edge of the input. When the total=> setpoint you would turn off the output.