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Lead/Lag Characteristics
2.1
Terminology and Definitions
◼
Lead (+) Drive
- The drive that controls communications of the entire system. Note the designation of
(
“+”
) for the Lead (+) drive. There is only one Lead (+) drive. The Lead (+) drive is a drive that receives
transducer feedback. The “+” designation is shown on the LCD display. See
Section 3, LCD
◼
Main Drive
- A drive that is performing the PI Control. There is only one Main drive. The Lead (+) drive
can be the Main drive, but when a 2
nd
drive is staged, the 2
nd
drive now takes over the PI Control and
becomes the Main drive. The PI Control is shifted from the Lead (+) to the Main drive. The Lead (+)
drive now becomes a Lag drive but still controls communications, but not PI Control.
◼
Lag or Aux Drive
- A drive that operates under the control of the Main drive. There can be up to 7
Lag (or AUX) drives as one is a Main drive.
2.2
Characteristics of Lead/Lag Operation
◼
Each drive’s ID must be set differently with COM-01 (Int485 St ID).
◼
Each motor/pump is connected to a drive. The Lead (+) drive controls communications of the entire
system. Note the designation of (
“+”
) on the LCD display of the Lead (+) drive.
◼
Lag (or Aux) drives when staged become the Main PI controlled drive as they take over the PI Control
of the system. The PI Control shifts to each Lag (or Aux) drive making it the Main PI controlled drive.
The Lead (+) drive now becomes a Lag (or Aux) drive but retains the (+) for communications.
◼
Lag (or Aux) drives are controlled based on Lead (+) drive operation (Follow Lead or Fixed Lag) and
the PI function of the Main drive.
◼
A Lead/Lag system with only one transducer connected to one drive can only have one Lead (+) drive.
Lag drives are set to Network feedback.
◼
A Lead/Lag system with each drive receiving feedback, the Lead (+) drive can change. Feedback can
be from individual transducers to each drive or from one transducer wired to all drives (series 4-20mA
loop).
◼
If the Lead (+) drive is manually stopped, trips or malfunctions, a Lag (or Aux) drive takes over as the
Lead (+) drive and continuously controls the system. The Lag (or Aux) drive must be connected with
transducer (feedback) to become the Lead (+) drive.
◼
A Lead/Lag system with each drive receiving feedback, the first drive to be put into AUTO state (button
on Keypad) becomes the Lead (+) drive.
◼
A Lead/Lag system with each drive receiving feedback, when all drives are powered up at the same
time, the drive with the lowest ID (COM-01, Drive ID) becomes the Lead (+) drive.
◼
Drives will power up to their last operating state. If in AUTO, will power up to Auto. If OFF, will power
up to Off.
◼
Alternation (AP1-49) can be set to FILO, FIFO or based on operating time where the operating time
of each drive/motor/pump is evenly distributed.
Summary of Contents for RSi H2P Series
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