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APPENDIX D — VFD INFORMATION
On units equipped with optional supply fan and/or exhaust
fan VFDs, the fan speed is controlled by a 3-phase VFD. The
supply fan VFD is located in the supply fan section behind an
access door. The exhaust fan VFD is located on the back wall
of the unit return section.
The N Series units use ABB VFDs. The VFDs communi-
cate to the ComfortLink MBB over the local equipment net-
work (LEN). The VFD speed is controlled directly by the
ComfortLink controls over the LEN. The interface wiring for
the VFDs is shown in Fig. A and the terminal designations are
shown in Table A. The VFD has a keypad display panel that
can be used for Service Diagnostics and setting the initial VFD
parameters required to allow the VFD to communicate on the
LEN. Additional VFD parameters are set by the ComfortLink
controls and sent to the VFD over the LEN at power up of the
VFD. The VFD faults can be reset with the VFD keypad or
through the ComfortLink controls (Alarms
R.CUR =Yes).
Table B outlines the VFD parameters required to initialize
communication over the ComfortLink LEN. These parameters
must be set correctly for any communications to occur. These
parameters come preset from the factory. If the VFD is
replaced, these parameters must be set at the initial power up of
the drive. This can be accomplished by running the Carrier As-
sistant through the VFD keypad (see START-UP WITH THE
CARRIER ASSISSTANT section), or setting each of the pa-
rameters individually.
After the parameters in Table B have been set, the Com-
fortLink controls configure the additional parameters listed in
Tables C and D automatically. These parameter configurations
are sent to the VFD at every power up. The parameters listed in
Table C have corresponding ComfortLink configurations
(Configuration
IAQ
S.VFD and Configuration
IAQ
E.VFD). The parameters in Table D are hard-coded to be set as
listed.
After configuration Tables C and D have been sent to the
VFD, the drive continues to send and receive information from
the ComfortLink controls. This information is outlined in Ta-
bles E and F. Table E lists the information the VFD sends to the
ComfortLink controls, and Table F lists the information the
ComfortLink controls send to the VFD. These tables are updat-
ed at every scan the ComfortLink controls perform of the LEN.
This occurs approximately once every second.
Table A — VFD Terminal Designations
TERMINAL FUNCTION
U1 Three-Phase Main Circuit Input Power Supply
V1
W1
U2 Three-Phase AC Output to Motor, 0 V to Maximum Input Voltage Level
V2
W2
X1-11 (GND) Factory-supplied jumper
X1-12 (D-COM)
X1-10 (+24 V) Factory-supplied jumper
X1-13 (DI-1)
X1-10 (+24 V) Start Enable 1 (Factory-supplied jumper). When opened the drive goes to emergency stop.
X1-16 (DI-4)
X1-28 (SCR) Factory wired for local equipment network LEN communication
X1-29 (B+)
X1-30 (B-)
X1-31 (AGND)
X1-32 (SCR)
+24 V
GND
DCOM
DI-1
DI-2
DI-3
DI-4
DI-5
DI-6
SCR
B(+)
A(-)
AGND
SCR
10 11 12 13 14 15 16 17 18 28 29 30 31 32
LEN connection from ComfortLink
Terminal X1
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