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ADVANCED APPLICATION OPTIONS
MultiDrive Feature (mobile app only)
Lag: A Lag drive becomes active when the Master determines that the setpoint cannot be met by the Lead.
•
Before a Lag drive can start, it must be in Auto mode, with its own run command, and a run command
from the Master.
•
Lag Speed sets the Lag drive to run either on its own PID or at a fixed frequency. If a Lag drive is alter-
nated to become a Lead, it automatically switches to PID mode.
NOTE: If a Lag is operating in PID mode, it could possibly run at a higher frequency than the Lead at times as
the overall system balances itself.
Sequence Assignment
The system has the capability to rotate assigned drive roles through the network based on the parameter
setting Alternation. There are two possible scenarios:
Alternation–Disabled: This setting might be appropriate when the system primarily operates at a low flow
rate and uses the Lag pumps as backups when needed.
•
In this case, the Lead pump could be sized for efficiency at a lower flow rate and would always be the
first to start.
•
The Lead/Master would regulate the pressure of the system using its own PID sensor.
•
The Lag pumps could be sized differently and could either use their own PID or be set to run at a spe-
cific frequency.
Alternation–Timer: This scenario might be used to rotate the Lead role to distribute wear on a system with
continuous operation.
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In this case, the system roles would be rotated after running for a specific time, set in Alternation Timer.
•
In addition to balancing usage, this practice would help ensure the proper functioning of Lag units that
might otherwise be idle for extended periods.
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The best practice would be to size and program all pumps/drives the same.
In all cases, the Master will be the drive with the lowest drive ID number (i.e. VFD 1).
If the Master faults, it is switched to Off or to Hand Mode. The Master role is then shifted to the drive with the
next lowest ID. If there is a break in communication, the lowest drive ID on any remaining functional network
is assigned the Master role.
Example Rotation Pattern:
Event
System Start
First Alteration
Master/Lag 4
Second Alteration
Master/Lag 3
VFD 1 Fault
Fault Handling
If a fault occurs on a Lead or Lag drive, the Master will remove the drive from the sequence, rotate the iden-
tity of the remaining drives, and initiate a start command for the next drive in sequence.
If any drive detects an Over Pressure or Broken Pipe, it communicates the condition to the Master, which
then stops operation of the entire system. All other faults are local to an individual drive.
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VFD 1
VFD 2
Master/Lead
Lag 1
Lead
Lag 4
Not Ready
Master/Lag 3
VFD 3
VFD 4
Lag 2
Lag 3
Lag 1
Lag 2
Lead
Lag 1
Lead
Lag 1
VFD 5
Lag 4
Lag 3
Lag 2
Lag 2
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