Honeywell SmartVFD HVAC MR4 User Manual page 154

HVAC A
PPLICATION
MULTI-PUMP USE
A motor/motors are connected/disconnected if the PID controller is not able to keep the process
value or feedback within the defined bandwith around the setpoint.
Criteria for connecting/adding motors (also see Figure 24):
• Feedback value outside the bandwidth area.
• Regulating motor running at a "close-to-max" frequency (-2Hz)
• Conditions above are fulfilled for a time longer than the bandwidth delay
• There are more motors available
Motor 2
Motor 3
Criteria for disconnecting/removing motors:
• Feedback value outside bandwidth area.
• Regulating motor running at a "close-to-min" frequency (+2 Hz)
• Conditions above are fulfilled for a time longer than the bandwidth delay
• There are more motors running than the regulating one.
M3.14.2 I
NTERLOCK FUNCTION
Interlocks can be used to tell the Multi Pump system that a motor is not available e.g. because
of the motor is removed from the system for maintenance or bypassed for manual control.
Enable this function to use the interlocks. Choose the needed status for each motor by digital
inputs (parameters M3.5.1.26 to M3.5.1.29). If the input is closed (TRUE) the motor is available
for the Multi Pump system, otherwise it will not be connected by the Multi Pump logic.
Bandwidth Setpoint
Feedback
Figure 24.
Delay
Drive is running at maximum
or close to maximum frequency
Honeywell
• 82
100K24.fh11
ON
OFF
ON
OFF