Plc 5

3 pump control

Attached should be the pictures of the front panel and the SLC 5/03. Thanks for the feedback on the Ethernet connection. WOW! Don't need any damage to my computer.
This MCC cabinet has been purchased from another golf course since the old one was washed away and was using 2 motors at 240 volt. We will upgrade to 3 phase 480 volt and add another motor since their motor set up was saved and refurbished resulting in 3 motors and pump system.
Each motor will run a bank of sprinklers for an hour beginning at certain times (beginning at midnight and run sequentially then start over at midnight the next night and so on)
The pressure switches (press sw 1,2,3) will be installed on all three motors on the discharge of the pump to shut down the motor if pressure reaches 130 psi as overpressure protection.
The front panel (pictures) currently has on/off switches for pump 1 and 2 (top row). The bottom row has the Hand/off/Auto switch which I haven't put into the program yet.
The suction side of the pump will come from a pond with a foot valve which may need a priming system to prime the pumps. I will check on that. You will also notice vari-drive controls on the front panel. This drive system will not be used in this system as no manipulated flow control will be required as pumps and motors have been sized to run at full load and maximum pressure. Thank you

rcwalls said:

The pressure switches (press sw 1,2,3) will be installed on all three motors on the discharge of the pump to shut down the motor if pressure reaches 130 psi as overpressure protection.

Click to expand...

So let me see if I'm envisioning the sequence correctly:

1. Pump is running to a clogged pipe.
2. Pressure goes >130 PSI, tripping the switch.
3. Pump stops.
4. With no motive force behind it, pressure drops to <130 PSI.
5. Pressure Switch is now OK.

Does the pump restart in AUTO?
If not, when/how does it restart?
How does a human know that there is a problem, since the switch reads "OK"?

Great questions. I do not want the motor to restart so I need to review that again. The only equipment in the loop for each pump will be the pressure switch causing shut down. Of course the motor overloads will also shut down the motor, but that will be in the reset system. Manual reset. It would not be a bad idea to put a flag of some sort on the pressure switch to let us know that there was an over pressure, but I would not want the motor to restart until we can determine the cause of the over pressure. The intent here would be simplicity for cost reasons. This is a poor small town 9 hole golf course we th very little money and trying to keep there equipment cost down as we are volunteering no the labor, however we do want to keep the system safe and reliable to keep their future cost down. Thanks again for all of the feedback.

A good budget idea is to put a general "alarm" light on the panel for situations that require operator interaction. You could then have the alarm reset when the switch position is changed to OFF. The operator can then switch back to AUTO to attempt to run again.

An even better approach would be to use the HMI to display a list of alarms, if you're able to access it.

Thank you. Good idea