Page 36
Example 2 Alternating Control (pump down)
A sump is typically used to temporarily hold water or effluent, and when the
level reaches a specific point, the sump is pumped down, with the fluid being
transferred to another process.
In this example a blackbox with dB6 is being used to control pumps on a
pump down application, there are two pumps, and the duty pump is to be
alternated between the pumps.
This will operate as follows. During normal operation, pump 1 will come on
at 4.0 feet, and pump down to 1.5 feet. The setpoints are then shifted to pump
2, which will come on first next time.
During peak periods, when pump 1 cannot cope, pump 1 will come on at 4.0
feet, pump 2 will come on at 6.0 feet, and pump down to 1.5 feet. The
setpoints are then shifted to pump 2, which will come on first next time.
The 4 to 20mA output will be representative of level.
To Next Page
Loading...
Need help?
General
