Temperature Compensated Start; Carrier Comfort Network (Ccn) R Configuration - Carrier 48LC 04 Controls, Start-Up, Operation And Troubleshooting

II.FN = 2 (Always)
The indoor fan operation for II.FN =2 is the same as the operation
when IA.FN =1, except the algorithm is not limited to the occupied
periods only. The fan can be triggered on when the space is
occupied or unoccupied.

Temperature Compensated Start

This logic is used when the unit is in the unoccupied state. The
control will calculate early Start Bias time based on Space
Temperature deviation from the occupied cooling and heating set
points. This will allow the control to start the unit so that the space
is at conditioned levels when the occupied period starts. This is
required for ASHRAE 90.1 compliance. A space sensor is required
for non-linkage applications.
Setting Up the System
The settings for temperature compensated start can be found in the
local display under ConfigurationUNIT.
ITEM EXPANSION
TCS.C Temp.Cmp.Strt.Cool Factr
TCS.H Temp.Cmp.Strt.Heat Factr
Temp Comp Strt Cool Factr (TCS.C)
This is the factor for the start time bias equation for cooling.
Temp Comp Strt Heat Factr (TCS.H)
This is the factor for the start time bias equation for heating.
NOTE: Temperature compensated start is disabled when these
factors are set to 0.
Temperature Compensated Start Logic
The following conditions must be met for the algorithm to run:
S Unit is in unoccupied state.
S Next occupied time is valid.
S Current time of day is valid.
S Valid space temperature reading is available (sensor or CCN
network).
The algorithm will calculate a Start Bias time in minutes using the
following equations:
If (space temperature > occupied cooling set point)
Start Bias Time = (space temperature – occupied cooling set
point)* TCS.C
If (space temperature < occupied heating set point)
Start Bias Time = (occupied heating set point – space
temperature)*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, the fan is started and the 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 Economizer Free Cool mode is active when
temperature compensated start begins, the Unoccupied Free Cool
mode will be stopped.
NOTE: The maximum minutes Start Bias can be is 180.
Carrier Comfort Network (CCN)
It is possible to configure the ComfortLink control to participate as
an element of the Carrier Comfort Network (CCN) system directly
from the local display. This section will deal with explaining the
various programmable options which are found under the CCN
sub-menu in the Configuration mode.
The major configurations for CCN programming are located in the
local displays at ConfigurationCCN. See Appendix A.
RANGE UNITS CCN POINT
0 - 60 min TCSTCOOL
0 - 60 min TCSTHEAT
R Configuration
CCN Address (CCN.A)
This configuration is the CCN address the rooftop is assigned.
CCN Address (CCN.B)
This configuration is the CCN bus the rooftop is assigned.
CCN Baud Rate (BAUD)
This configuration is the CCN baud rate.
CCN Time/Date Broadcast (BRODB.TIM)
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 (BRODB.OAT)
If this configuration is set to ON, the control will periodically
broadcast its outside-air temperature at a rate of once every 30
minutes.
Global Schedule Broadcast (BRODB.GS)
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 (BRODB.ACK)
If this configuration is set to ON, then when any broadcasting is
done on the bus, this device will respond to and acknowledge.
Only one device per bus can be configured for this option.
Schedule Number (SCH.OSCH.N)
This configuration determines what schedule the control may
follow.
SCH.N = 0 The control is always occupied.
SCH.N = 1 he control follows its internal
T
time schedules. 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 T he control is either set up to
receive to a broadcasted time
schedule set to this number or
the control is set up to
broadcast its internal time
schedule (B.GS) to the network
and this is the global schedule
number it is broadcasting. If this
is the case, then the control still
follows its internal time
schedules.
Accept Global Holidays? (SCH.OHOL.G)
If a device is broadcasting 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 (SCH.OOV.TL)
This configuration allows the user to decide how long an override
occurs when it is initiated. 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 (SCH.O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.
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