United Technologies Carrier Weathermaker 48A2, Controls, Start-Up, Operation, Service, And Troubleshooting

Page: 73 / 208

73
TEMPERATURE COMPENSATED START LOGIC — The
following conditions must be met:
• Unit is in unoccupied state.
• Next occupied time is valid.
• Current time of day is valid.
• Valid space temperature reading is available (sensor or
DAV-Linkage).
The algorithm will calculate a Start Bias time in minutes us-
ing the following equations:
If (space temperature > occupied cooling setpoint)
Start Bias Time = (space temperature – occupied cooling
setpoint)* TCS.C
If (space temperature < occupied heating setpoint)
Start Bias Time = (occupied heating setpoint – space tem-
perature)* TCS.H
When the Start Bias Time is greater than zero the algorithm
will subtract it from the next occupied time to calculate the new
start time. When the new start time is reached, the Temperature
Compensated Start mode is set ( Operating Modes

MODE

T.C.ST ), the fan is started and unit controlled as in an occupied
state. Once set, Temperature Compensated mode will stay on
until the unit goes into the Occupied mode. The Start Bias
Time will be written into the CCN Linkage Equipment Table if
the unit is controlled in DAV mode. If the Unoccupied Econo-
mizer Free Cool mode is active ( Operating Modes

HVAC =
“UNOCC FREE COOL”) when temperature compensated
start begins, the Unoccupied Free Cool mode will be stopped.
Carrier Comfort Network ® (CCN) System —
It
is possible to configure the Comfort Link control to participate
as an element of the Carrier Comfort Network (CCN) system
directly from the local display. This section will deal with ex-
plaining the various programmable options which are found
under the CCN sub-menu in the Configuration mode.
The major configurations for CCN programming are locat-
ed in the local displays at Configuration

CCN . See Table 71.
CCN Address ( CCNA ) — This configuration is the CCN ad-
dress the rooftop is assigned.
CCN Bus Number (
CCNB ) — This configuration is the CCN
bus the rooftop is assigned.
CCN Baud Rate (
BAUD ) — This configuration is the CCN
baud rate. For units equipped with the optional UPC, the CCN
Baud Rate must be set to 9600.
CCN Time/Date Broadcast (
TM.DT ) — If this configuration
is set to ON, the control will periodically send the time and date
out onto the CCN bus once a minute. If this device is on a CCN
network then it will be important to make sure that only one
device on the bus has this configuration set to ON. If more than
one time broadcaster is present, problems with the time will
occur.
NOTE: Only the time and date broadcaster can perform
daylight savings time adjustments. Even if the rooftop is stand
alone, the user may want to set this to ON to accomplish the
daylight/savings function.
CCN OAT Broadcast (
OAT.B ) — If this configuration is set
to ON, the control will periodically broadcast its outside-air
temperature at a rate of once every 30 minutes.
CCN OARH Broadcast (
ORH.B ) — If this configuration is
set to ON, the control will periodically broadcast its outside air
relative humidity at a rate of once every 30 minutes.
CCN OAQ Broadcast (
OAQ.B ) — If this configuration is set
to ON, the control will periodically broadcast its outside air
quality reading at a rate of once every 30 minutes.
Global Schedule Broadcast (
G.S.B ) — If this configuration is
set to ON and the schedule number ( SCH.N ) is between 65 and
99, then the control will broadcast the internal time schedule
once every 2 minutes.
CCN Broadcast Acknowledger (
B.ACK ) — If this configura-
tion is set to ON, then when any broadcasting is done on the
bus, this device will respond to and acknowledge. Only one de-
vice per bus can be configured for this option.
Schedule Number (
SCH.N ) — This configuration determines
what schedule the control may follow.
SCH.N = 0 The control is always occupied.
SCH.N = 1 The control follows its internal time sched-
ules. The user may enter any number
between 1 and 64 but it will be overwritten
to “1” by the control as it only has one
internal schedule.
SCH.N = 65-99 The control is either set up to receive to a
broadcasted time schedule set to this num-
ber or the control is set up to broadcast its
internal time schedule ( G.S.B ) to the net-
work and this is the global schedule number
it is broadcasting. If this is the case, then the
control still follows its internal time sched-
ules.
Accept Global Holidays? ( HOL.T ) — If a device is broad-
casting the time on the bus, it is possible to accept the time yet
not accept the global holiday from the broadcast message.
Override Time Limit (
O.T.L ) — This configuration allows
the user to decide how long an override occurs when it is initi-
ated. The override may be configured from 1 to 4 hours. If the
time is set to 0, the override function will become disabled.
Timed Override Hours (
OV.EX ) — This displays the current
number of hours left in an override. It is possible to cancel an
override in progress by writing “0” to this variable, thereby
removing the override time left.
Table 71 — CCN Configuration
* For units equipped with optional UPC, the CCN Baud Rate must be set to 3.
ITEM EXPANSION RANGE UNITS POINT DEFAULT
CCN CCN CONFIGURATION
CCNA CCN Address 1 - 239 CCNADD 1
CCNB CCN Bus Number 0 - 239 CCNBUS 0
BAUD CCN Baud Rate 1 - 5 CCNBAUDD 3*
BROD CCN BROADCST DEFINITIONS
TM.DT CCN Time/Date Broadcast ON/OFF CCNBC On
OAT.B CCN OAT Broadcast ON/OFF OATBC Off
ORH.B CCN OARH Broadcast ON/OFF OARHBC Off
OAQ.B CCN OAQ Broadcast ON/OFF OAQBC Off
G.S.B Global Schedule Broadcst ON/OFF GSBC Off
B.ACK CCN Broadcast Ack'er ON/OFF CCNBCACK Off
SC.OV CCN SCHEDULES-OVERRIDES
SCH.N Schedule Number 0 - 99 SCHEDNUM 1
HOL.T Accept Global Holidays? YES/NO HOLIDAYT No
O.T.L Override Time Limit 0 - 4 HRS OTL 1
OV.EX Timed Override Hours 0 - 4 HRS OVR_EXT 0
SPT.O SPT Override Enabled ? YES/NO SPT_OVER Yes
T58.O T58 Override Enabled ? YES/NO T58_OVER Yes
GL.OV Global Sched. Override ? YES/NO GLBLOVER No