6 How to Program the Low Harmonic Drive
6.1 How to Program the Adjustable Frequency Drive
6.1.1 Parameter Set-up
Group
Title
Function
0-
Operation and Display
Parameters used to program the fundamental functions of the adjustable frequency drive and the LCP
including: selection of language; selection of which variables are displayed at each position in the display
(e.g., static duct pressure or condenser water return temperature can be displayed with the setpoint in
small digits in the top row and feedback in large digits in the center of the display); enabling/disabling
of the LCP keys/buttons; passwords for the LCP; upload and download of commissioned parameters to/
from the LCP and setting the built-in clock.
1-
Load / Motor
Parameters used to configure the adjustable frequency drive for the specific application and motor in-
cluding: open or closed-loop operation; type of application such as compressor, fan or centrifugal pump;
motor nameplate data; auto-tuning of the drive to the motor for optimum performance; flying start
(typically used for fan applications) and motor thermal protection.
2-
Brakes
Parameters used to configure braking functions of the adjustable frequency drive which although not
common in many HVAC applications, can be useful on special fan applications. Parameters including: DC
braking; dynamic/resistor braking and overvoltage control (which provides automatic adjustment of the
deceleration rate (auto-ramping) to avoid tripping when decelerating large inertia fans)
3-
Reference / Ramps
Parameters used to program the minimum and maximum reference limits of speed (RPM/Hz) in open-
loop or in actual units when operating in closed-loop); digital/preset references; jog speed; definition of
the source of each reference (e.g., which analog input the reference signal is connected to); ramp-up
and ramp-down times and digital potentiometer settings.
4-
Limits / Warnings
Parameters used to program limits and warnings of operation including: allowable motor direction; min-
imum and maximum motor speeds (e.g., in pump applications it is typical to program a minimum speed
to approx 30-40% to ensure pump seals are adequately lubricated at all times, avoid cavitation and
ensure adequate head is produced at all times to create flow); torque and current limits to protect the
pump, fan or compressor driven by the motor; warnings for low/high current, speed, reference, and
feedback; missing motor phase protection; speed bypass frequencies including semi-automatic set-up
of these frequencies (e.g., to avoid resonance conditions on cooling tower and other fans).
5-
Digital In / Out
Parameters used to program the functions of all digital inputs, digital outputs, relay outputs, pulse inputs
and pulse outputs for terminals on the control card and all option cards.
6-
Analog In / Out
Parameters used to program the functions associated with all analog inputs and analog outputs for the
terminals on the control card and General Purpose I/O option (MCB101) (note: NOT Analog I/O option
MCB109, see parameter group 26-00) including: analog input live zero timeout function (which, for ex-
ample, can be used to command a cooling tower fan to operate at full speed if the condenser water
return sensor fails); scaling of the analog input signals (for example, to match the analog input to the
mA and pressure range of a static duct pressure sensor); filter time constant to filter out electrical noise
on the analog signal which can sometimes occur when long cables are installed; function and scaling of
the analog outputs (for example, to provide an analog output representing motor current or kW to an
analog input of a DDC controller) and to configure the analog outputs to be controlled by the BMS via a
high level interface (HLI) (e.g., to control a chilled water valve) including ability to define a default value
of these outputs in the event of the HLI failing.
8-
Communication and Options Parameters used for configuring and monitoring functions associated with the serial communications /
high level interface to the adjustable frequency drive
9-
Profibus
Parameters only applicable when a Profibus option is installed.
10-
CAN Fieldbus
Parameters only applicable when a DeviceNet option is installed.
11-
LonWorks
Parameters only applicable when a Lonworks option is installed.
Table 6.1: Parameter Groups
VLT HVAC Low Harmonic Drive Instruction
Manual
6 How to Program the Low Harmonic Drive
MG.16.A1.22 - VLT
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