I am setting up an EPS for a client that has logic within their SCADA system to rotate which well is being called for according to a fixed sequence. For example, if well 1 was the last well to operate, the next time a well is needed well 2 is started... Is there a way to recreate this rotation within the EPS controls?
Hello Ken,
The following link as information on how to do this, as well as a sample model: Controls for alternating or cycling between pumps. Basically, you would use a couple of dummy pipes to help with the simulation, changing the status of the dummy pipe to act as a sort of counter. The link above goes into details on doing this. Please let us know if you have any questions on this.
Regards,
Scott
I think I can make that work for what I need. Just a bit more complicated as I have three wells to cycle and am starting or stopping the wells based on elevations from two different elevated tanks...
Please see below for a summary of my proposed control logic. My intent is to use a series of "and" statements to represent the items in parenthesis with those conditions detailed in the tables below. CP1 and CP2 are fake control pipes I plan on running between two reservoirs that will otherwise be disconnected from the system. T1, T2, Pmp-On and Pmp-Off values are my tank levels and start and stop points. Any glaring mistakes before I start detailing all this out within WaterGEMS? Thanks...
Summary of Needed Control Language
Starting Pumps
IF (Combo 1) and (next well = 1) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 1 = on and (Next Well = 2)
IF (Combo 1) and (next well = 2) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 2 = on and (Next Well = 3)
IF (Combo 1) and (next well = 3) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 2 = on and (Next Well = 1)
IF (Combo 2) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 2 = on and (Next Well = 3)
IF (Combo 3) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 3 = on and (Next Well = 1)
IF (Combo 4) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 1 = on and (Next Well = 2)
IF (Combo 5) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 3 = on and (Next Well = 1)
IF (Combo 6) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 2 = on and (Next Well = 3)
IF (Combo 7) and T1 < Pmp-On1 or T2< Pmp-On2, Then Pmp 2 = on and (Next Well = 3)
Stopping Pumps
IF (Combo 2) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 1 = off
IF (Combo 3) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 2 = off
IF (Combo 4) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 3 = off
IF (Combo 5) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 1 = off
IF (Combo 6) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 3 = off
IF (Combo 7) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 2 = off
IF (Combo 8) and (Next Well = 1) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 1 = off
IF (Combo 8) and (Next Well = 2) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 2 = off
IF (Combo 8) and (Next Well = 2) and T1 > Pmp-Off1 or T2> Pmp-Off2, Then Pmp 3 = off
Eight Possible Running states
Combo #
Wells On
Well 1
Well 2
Well 3
1
All off
Off
2
Well 1 on
On
3
Well 2 on
4
Well 3 on
5
Well 1 and 2 on
6
Well 1 and 3 on
7
Well 2 and 3 on
8
All On
Next Well to Start
Well #
CP1
CP2
Open
Closed
I don't see any glaring mistakes, but from experience troubleshooting controls I find it easier when they are separated into the most simplistic or a more simplistic form rather than using combination control statements. It might take longer to enter the controls, but if one part of the control is not working it's easier to find the mistake.
Mark