M
I'm very new to building any kind of automation, so please forgive my ignorance of best practices, PLC programming, etc. I'm coming to people who are a lot smarter than I am to try and find a solution.
I'm working on a project for a friend. It's a semi-automated bottle filling station. You line the bottles up with the nozzles, select the bottle size and press the cycle start button.
I'm using a PLC to control a 6 valve manifold to fill 6 bottles at a shot. The manifold is fed by an air operated double diaphragm pump at 20 PSI. I'm using time and pressure as my "variables" in controlling the amount of fluid that is dispensed to the bottles. I had thought about using flow meters to help, however my knowledge level is limited and budget is the main constraint on the project.
The problem I'm having is that I'll get everything dialed in to where it's filling the bottles consistently to the volume needed. Then I'll stop processing or shut the system down (even for 30 minutes), then when I start back up (with the pressure being the same, the timers being the same, etc.) it will no longer throw the correct amount of fluid. It usually throws really heavy for about 15-20 cycles. Then it gradually returns to the original amount or close to it.
My suspicion is that it has something to do with the system staying pressurized over a long period of time without cycling, but I'm not sure. Does anyone have an idea of what may be happening? How to test that hypothesis or for what's really happening? Do you need more information?
Any help would be greatly appreciated.
I'm working on a project for a friend. It's a semi-automated bottle filling station. You line the bottles up with the nozzles, select the bottle size and press the cycle start button.
I'm using a PLC to control a 6 valve manifold to fill 6 bottles at a shot. The manifold is fed by an air operated double diaphragm pump at 20 PSI. I'm using time and pressure as my "variables" in controlling the amount of fluid that is dispensed to the bottles. I had thought about using flow meters to help, however my knowledge level is limited and budget is the main constraint on the project.
The problem I'm having is that I'll get everything dialed in to where it's filling the bottles consistently to the volume needed. Then I'll stop processing or shut the system down (even for 30 minutes), then when I start back up (with the pressure being the same, the timers being the same, etc.) it will no longer throw the correct amount of fluid. It usually throws really heavy for about 15-20 cycles. Then it gradually returns to the original amount or close to it.
My suspicion is that it has something to do with the system staying pressurized over a long period of time without cycling, but I'm not sure. Does anyone have an idea of what may be happening? How to test that hypothesis or for what's really happening? Do you need more information?
Any help would be greatly appreciated.