AB controlling solenoid shift Diaphragm Pump

I am modifying a machine to have a dual diaphragm pump controlled by a shifting solenoid. Basically every time the solenoid is energized the pump intakes one diaphragm and the other outputs, when de-energizing the opposite happens. It feeds a hopper on a load cell. I need to control the feed into the hopper better so I am using this "shift" kit for the pump. Metering pump is out of the question. My question is, how do I handle it with the PLC.

I have a AB Micro Logix 1100 120V. It currently has a 120V relay output going to the a solenoid for the pump just opening or closing the solenoid. Now I need to "pulse" the signal to a solenoid to the point that the load cell shows the desired weight or is close and can slow the pulse or run a pump cycle and check weight when it gets close to desired weight. Or I can take the desired weight and divide it by the known volume of each pump cycle, get it close that way then do the pump cycle and check weight.

I don't need to separate the energize and de-energize pump cycles, I should be OK with energizing and de-energizing the solenoid at the end to reach my setpoint. The divide for volume solution wouldn't be ideal. There will actually be two pumps, one will be pumping a solution that is always the same, the other pump will be pumping sulfuric acid and sometimes we will be using slightly different gravities, but they will all be close. Even running that solution I'm not sure what would be the best way to program that so it wasn't just checking the weight after each cycle. That seems like it would be slow. I do need to run this quickly if possible.

I have basic PLC programming skills and have programmed them to run basic things of outputting to air solenoids and monitoring input signals, but I'm not sure how to handle this.

Please let me know if any of this makes sense.

Thanks,
Mat

Use 2 Timers to create a pulse.

XIO T4:1/DN TON T4:0 0.01 500 0
XIC T4:0/DN TON T4:1 0.01 500 0

IF TIMER 1 IS NOT DONE THEN RUN TIMER 0
IF TIMER 0 IS DONE THEN RUN TIMER 1


Timer 0 Done Bit will Pulse ON/OFF according to Presets

Then IF CURRENT WEIGHT <= 90% OF PRESET WEIGHT THEN MOVE 500 INTO TIMER 0 AND TIME 1 PRESET VALUE.

When CURRENT WEIGHT > 90% THEN MOV 1000 INTO TIMER PRESET VALUES.

You can adjust Timer Preset to Suit your needs and may be able to run full pulse rate to 98% before checking for stop condition.

relays are not designed to used as a pulse shorter as about 0.5 seconds, they are just to slow, in that time your pump has done 50 pulses.

you can slow it down with a second solenoidvalve but here the air is controlled with a needle valve.

OK, that gives me something to start with. Thanks for the help, I will let you know if I have problems.

Shooter- I thought about something like that, I know it's not ideal relays. But knowing how people are around here with accuracy, I think I can get a lot closer to their weights this way.

This type of pump discharges a fairly constant volume every stroke, so counting strokes provides a decent flow signal.

If you want to cycle rapidly use solid state relays.

Tom, that was what I was counting on. I will look into the solid state relays. Thanks for th input.