Operating instructions

Dedicated fan features
Extends BMS capacity
When integrated into the BMS
network, all the HVAC Drive I/O points
are available as remote I/O to extend
the capacity of the BMS. For example,
room temperature sensors (Pt1000/
Ni1000) can be directly connected.
With the VLT® Sensor Input Card
option the motor is protected from
overheating in the bearings and
windings. The individual sensor tem-
perature is visible as a read out in the
display or by fi eld bus.
Resonance Monitoring
By pressing a few buttons on the
Local Control Panel the drive can be
set to avoid frequency bands at which
connected fans create resonances in
the ventilation system. This reduses
vibration noise and wear on
equipment.
Stairwell Pressurisation
In the event of fi re, the VLT® HVAC
Drive can maintain a higher level of
air pressure in stairwells than in other
parts of the building and ensure that
fi re escapes remain free of smoke.
Lower AHU costs
The VLT® HVAC Drive is fi tted with a
built-in Smart Logic Controller and
four auto tune PID controllers and can
control air handling functions with
fans, valves and dampers. The build
ing management’s DDC tasks are
redused and valuable data points (DP)
are free for other use.
User-friendly, distributed
intelligence and reduced
power consumption are bene-
fi cial for fan applications.
Velocity-to-fl ow conversion
The VLT® HVAC Drive is able to
convert velocity pressure sensor
values into fl ow values. Operators can
therefore set the drive up to provide a
fi xed fl ow or fi xed diff erential fl ow.
This way both comfort and energy
consumption are optimized. Using a
pressure sensor instead of a fl ow
sensor saves money.
Intelligent AHU functions
The VLT® HVAC Drive handles logical
rules and inputs from sensors, real-
time functionality, and time-related
actions. This enables the HVAC Drive
to control a wide range of functions,
including:
■ Weekend and working-day
operations
■ Cascaded P-PI for temperature
control
■ Multi-zone “3” control
■ Flow balancing between fresh
and outlet air
■ Belt monitoring
Fire Override Mode
Fire Override Mode prevents the
VLT® HVAC Drive from stopping for
self-protecting reasons. In this mode
it will continue vital fan operation
regardless of control signals, warnings
or alarms.
4 x PID controller
(Individual set points/feed backs)
■ 1 PID for closed loop control
of the motor connected to the
drive
■ 3 PID for external closed loop
control of HVAC equipment
■ Auto-tuning of all 4 PID loops
■ Eliminates the need for
other controllers
■ Provides fl exibility for the BMS
and reduces the load on the
central BMS
The drive controller uses an input
sensor that measures pressure,
temperature, or other variables to
change the speed on the motor
connected to the VLT® HVAC Drive,
by adjusting the output frequency
to match the varying load.
The additional 3 PID controllers
can be used for external sensors
(i.e. pressure, temperature, fl ow) to
control heating/cooling coil valves,
outside/return/exhaust dampers
or other external HVAC
components.
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