Carrier 48/50PM C16-28 - Manual (Page 71)

71
Main Base Board (MBB)
See Fig. 40 and Table 23. The MBB is the center of the
ComfortLink
t control system. It contains the major portion of the
operating software and controls the operation of the unit. The
MBB continuously monitors input/output channel information
received from its inputs and from the Economizer Control Board
(ECB). The MBB receives inputs from thermistors and transducers.
The MBB also receives the Current Sensor inputs for compressors
and other discrete or digital inputs. The MBB reads space
temperature (SPT) from either a T-55, T-56 or T-58 device and
space temperature offset (SPTO) from a T-56 device. See
Field-Installed Accessories section. The MBB controls 9 relays.
NOTE: The Main Base Board (MBB) has a 3-position instance
jumper that is factory set to ‘1.’ Do not change this setting.
CEPL130346-01
STATUS
LEN
J1 J2
J4
J3
J5
J6
J7 J8 J9
J10
CCN
RED LED - STATUS GREEN LED -
LEN (LOCAL EQUIPMENT NETWORK) YELLOW LED -
CCN (CARRIER COMFORT NETWORK)
INSTANCE JUMPER (SET TO 1)
C07026
Fig. 40 − Main Base Board (MBB)
48/50PG and PM