Pump Control

I'm using Unity Pro XL and requires some assistance with the following.

1. I have 3 Blowers to control in seq. 1 will start up and then the next and the third will be standby and must Flip Flop between them.
2. When Starting up, the one Blower must start-up at a desired speed until the Setpoint has been changed by an external Command. When the command has been recieved, then the Second Blower must Start, BUT the original speed setpoint will fall away and the TWO Blowers will be controlled with the external setpoint, but devided by two so that the two blowers will run at half each of the setpoint.

Hope the above makes sense and hope there is someone that can assist with the logic using Function Blocks

Thanks

For the first part use a bit to indicate which blower (pump?) is lead, which is lag, and which is standby. You don't designate if the lead/lag/standby sequence is operator set or if alternation takes place on stopping a blower when two are running (first on/first off) or if alternation is to take place weekly or such.

If these are centrifugal blowers (pumps) I suggest you use flow for the setpoint and adjust speed to maintain it, since performance with one running an two running is likely to be different.

If one unit is running pass the setpoint directly to the control loop. If two are running divide the setpoint by two and then pass it to the control loop.

Thanks for the feedback. The Blowers does not have a certain seq and they will have to operate in a Flip Flop state with the three Blowers. IE. If Blower 1 starts 1st, Blower 2 will start second , if healthy conditions are present and then the third will be standby and so on.

This is pretty standard stuff for a programmer. Have you at least tried to write any code yet? If so, share what you've done.