178
APPENDIX C — VFD INFORMATION
On variable air volume units with optional VFD, the supply fan
speed is controlled by a 3-phase VFD. The VFD is located in
the supply fan section behind a removable panel. The VFD
speed is controlled directly by the ComfortLink controls
through a 4 to 20 mA signal based on a supply duct pressure
sensor. The VFD has a display, which can be used for service
diagnostics, but setup of the building pressure and control loop
factors should be done through the scrolling marquee display.
The VFD is powered during normal operation to prevent con-
densation from forming on the boards during the off mode and
is stopped by driving the speed to 0 (by sending a 4 mA signal
to the VFD).
The A Series units use ABB VFDs. The interface wiring for the
VFDs is shown in Fig. A. The VFD connects through an isolation
board to the 4 to 20 mA RCB board. Terminal designations are
shown in Table A. Configurations are shown in Table B.
Table A — VFD Terminal Designations
Table B — VFD Configurations
TERMINAL FUNCTION
U1
V1
W1 Three-Phase Main Circuit Input Power Supply
U2
V2 Three-Phase AC Output to Motor, 0 V to
W2 Maximum Input Voltage Level
X1-11 (GND)
X1-12 (COMMON) Factory-supplied jumper
X1-10 (24 VDC)
X1-13 (DI-1) Run (factory-supplied jumper)
X1-10 (24 VDC) Start Enable 1 (Factory-supplied jumper). When
X1-16 (DI-4) opened the drive goes to emergency stop.
X1-2 (AI-1)
X1-3 (AGND) Factory wired for 4 to 20 mA remote input
PARAMETER GROUP PARAMETER TITLE PARAMETER INDEX CARRIER DEFAULT
Start-Up Data
LANGUAGE 9901 ENGLISH
APPLIC MACRO 9902 HVAC Default
MOTOR CTRL MODE 9904 SCALAR: FREQ
MOTOR NOM VOLT 9905 460v
MOTOR NOM CURR 9906 *TBD*
MOTOR NOM FREQ 9907 *60 Hz*
MOTOR NOM SPEED 9908 1750 rpm
Start/Stop/Dir
EXT1 COMMANDS 1001 DI-1
DIRECTION 1003 REVERSE
Analog Inputs
MINIMUM AI1 1301 20.0 %
MAXIMUM AI1 1302 100.0 %
Relay Outputs
RELAY OUTPUT 1 1401 STARTED
RELAY OUTPUT 2 1402 RUN
RELAY OUTPUT 3 1403 FAULT (-1)
System Controls
RUN ENABLE 1601 NOT SELECTED
START ENABLE 1 1608 DI-4
OVER RIDE
CONST SPEED 1201 3 (DI3)
CONST SPEED 1 1202 60 Hz
STOP FUNCTION 2102 COAST
Accel/Decel
ACCELER TIME 1 2202 30.0s
DECELER TIME 1 2203 30.0s
MOTOR SWITCHING FREQ 2606 8 kHz
To Next Page
Loading...
