Controller Operation - SJE VFDC-3000 Manual Del Usario

Automatic Operation
The controller will monitor the status of the automatic switch input for each pump and will add or remove the
operation of each pump based on the status of this input. Only the pumps in automatic mode and without any
active fault conditions, shall be included in the Lead/Lag sequencing and operation.
Normal Operation (Only One Pump Needed)
The lead pump starts when system pressure drops the Start Lead Differential Pressure below the Setpoint
Pressure. The lead pump runs, and its speed is controlled via PID control. If the lead pump's speed falls
below the Sleep Frequency for the Sleep Delay Time, the lead pump's operation shall be suspended.
Normal Operation (Two Pumps Needed)
The lead pump starts when system pressure drops the Start Lead Differential Pressure below the Setpoint
Pressure. The lead pump runs, and its speed is controlled via PID control. If the lead pump cannot keep up
with the demand for water, running at the Maximum Frequency and the system pressure drops to the Start
Lag Differential Pressure below the Setpoint Pressure, the lead pump shall be held at Maximum Frequency
and the speed of the lag 1 pump, which is the next pump in the sequence after the lead pump, shall have its
speed controlled via PID control. If the system pressure exceeds the Stop Lag Differential Pressure above
the Setpoint Pressure, and the lag 1 pump is operating at the Minimum Frequency, the lag 1 pump output
shall be suspended, and the lead pump speed is controlled via PID control. If the lead pump's speed falls
below the Sleep Frequency for the Sleep Delay Time, the lead pump's operation shall be suspended.
Normal Operation (Three Pumps Needed)
The lead pump starts when system pressure drops the Start Lead Differential Pressure below the Setpoint
Pressure. The lead pump runs, and its speed is controlled via PID control. If the lead pump running at the
Maximum Frequency cannot keep up with the demand for water and the system pressure drops to the Start
Lag Differential Pressure below the Setpoint Pressure, the lead pump shall be held at Maximum Frequency
and the speed of the lag 1 pump, which is the next pump in the sequence after the lead pump, shall have
its speed controlled via PID control. If the lead pump and lag 1 pump cannot keep up with the demand for
water and the system pressure drops to the Start Lag Diff Pressure below the Setpoint Pressure, the next
pump in the sequence after the lag 1 pump, shall have its speed controlled via PID control. If the system
pressure exceeds the Stop Lag Differential Pressure above the Setpoint Pressure, and the lag 2 pump is
operating at the Minimum Frequency, the lag 2 pump output shall be suspended, and the lag 1 pump speed
is controlled via PID control. If the system pressure exceeds the Stop Lag Differential Pressure above the
Setpoint Pressure, and the lag 1 pump is operating at the Minimum Frequency, the lag 1 pump output shall
be suspended, and the lead pump speed is controlled via PID control. If the lead pump speed falls below the
Sleep Frequency for the Sleep Delay Time, the lead pump output shall be suspended.
Pump Sequencing
Current Pump Assignment
Lead
Pump 1
Pump 2
Pump 3
SJE ®

CONTROLLER OPERATION

Lag 1 Lag 2
Pump 2 Pump 3
Pump 3 Pump 1
Pump 1 Pump 2
Next Pump Assignment
Lead
Pump 2
Pump 3
Pump 1
11 VFDC-3000 Controller User Manual
Lag 1 Lag 2
Pump 3 Pump 1
Pump 1 Pump 2
Pump 2 Pump 3