Linkage; Carrier Comfort Network R (Ccn) Operation; Bacnet Network Operation; Alarm Handling - Carrier 48LC Series Controls, Start-Up, Operation And Troubleshooting

referred to as start bias time, or bias time. The algorithm to
calculate this bias time is called Temperature Compensated Start.
This is required for ASHRAE 90.1 compliance. When temperature
compensated start is running (TCS ACTIVE?) the control uses the
occupied set points to control the space.
When Temperature compensated start is enabled (ADAPTIVE
TCS?), no other configuration parameters are needed for this
algorithm, because the algorithm will automatically adjust the Bias
Time based on the data collected during the period of last time
optimal start. The inputs to the calculation algorithm includes space
temperature, unoccupied set points, occupied set points, outdoor air
temperature, and supply air temperature. Bias time is changed
dynamically per RTU operation.
When Temperature compensated start is disabled (ADAPTIVE
TCS?), the control will use the User Temperature compensated
Start bias time (USER TCS BIASTIME) in determining when to
start controlling to the occupied set points. If the User Temperature
compensated Start bias time (USER TCS BIASTIME) is set to
zero, the control will switch to the occupied setpoints at the time of
occupancy.

Linkage

The SystemVut controller will support 3Vt, VAV and VVT
zoning system on a CCN system or Open VVT and VAV systems
on a BACnet MS/TP System. All that is required is to configure
the Open or 3V Master zone to use the SystemVu rooftop unit as
its airsource. The SystemVu control will need to be configured for
the proper network protocol (BAS PROTOCOL) and set for Space
Sensor Control (UNIT CTRL TYPE). The SystemVu controller
will reply to the zoning system and change its operating parameters
to meet the demand of the zoning system. Status of this process can
be viewed in the airside linkage tab of the property pages in the
R
i- -Vu application or by viewing the linkage maintenance table
with a CCN tool.
Carrier Comfort Network
The SystemVu controller can be configured to connect to a CCN
system. The SystemVu controller has one RS- -485 BMS port that
can be configured from the local display for BACnet or CCN. The
BMS configuration parameters
SETTINGSNETWORK SETTINGS submenu. The first
configuration is the BMS system for CCN systems change this
configuration from BACnet to CCN then set the CCN BAUD rate,
the bus and element number and you will be able to find the
controller with any CCN tool then upload the CCN tables in the
controller for use by the tool.

BACnet Network Operation

The SystemVut controller is ready to connect to BACnet. The
SystemVu controller has one RS- -485 BMS port that can be
configured from the local display for BACnet or CCN. The default
setting is BACnet and the Default BACnet Baud rate is 76800. These
setting are found on the SETTINGSNETWORK SETTINGS sub
menu of the local display. There are four other settings for i- -Vu
compatibility and for setting the device ID and MAC address of the
controller. See the table below for assistance.
Before connecting to the BACnet system determine the system
requirements and use the following guide to configure the BACnet
settings. Then power the controller down, connect to the BACnet
MS/TP network and you are ready to discover your controller.
R
For i- -Vu systems with auto addressing desired the controller is
already set with the defaults from the factory ready to connect to
this type of system; just set the MAC address of the controller from
0 to 99 and then power down and connect to the network. The
router will find and send the network number to the controller and
the controller will set it device ID with the network base appended
by the Mac address.
For i- -Vu and other BACnet systems when it is required to send the
device ID to the controller change the ALC/i- -Vu auto ID scheme to
no and set the MAC address from 0 to 99 like before. Then connect to
R (CCN) Operation
can be found in
the network and write the device ID to the controller at the MAC
address you set. The controller will accept and retain the device ID
written to the device Id property of the object ID.
To manually set the device ID from the local display set the BACnet
auto/manual to manual. This allows use of the full range of 1 to 127
for the MAC address and set the device ID in the BACnet ID
selection of the local display. It can only be set from the local display
and will not accept a write to the device ID property in the object ID.
BACnet ID I---Vu Auto
Auto/Manual Scheme
Manual ON or OFF
Auto OFF
Auto ON

Alarm Handling

There are a variety of different alerts and faults in the system, the term
alarm is used to reference alerts and faults. Alerts are indicated by
AXXX (where XXX is the alert number) on the display and generally
R
signify a warning of some sort or the improperly functioning circuit
can restart without human interaction. If an fault occurs, indicated by
FXXX (where XXX is the fault number), a major function of the unit
is inoperable or the damaged circuit will generally not restart without
an alarm reset via the display or CCN.
The response of the control system to various alerts and faults depends
on the seriousness of the particular alert or fault. In the mildest case, an
alert does not affect the operation of the unit in any manner. An alert
can also cause a "strike." A "striking" alert will cause the circuit to
shut down for 15 minutes. This feature reduces the likelihood of false
alarms causing a properly working system to be shut down incorrectly.
If three strikes occur before the circuit has an opportunity to show that
it can function properly, the circuit will strike out, causing the
shutdown fault for that particular circuit. Once activated, the shutdown
fault can only be cleared via an alarm reset.
However, circuits with strikes will be given an opportunity to reset
the
their strike counter to zero. As discussed above, a strike typically
causes the circuit to shut down. Fifteen minutes later, that circuit will
once again be allowed to run. If the "troubled" circuit runs
continuously for a user defined time (SETTINGSUNIT
CONFIGURATIONSCOOLINGSTRIKE CLEAR TIME) with
no detectable problems the strike counter will be reset to zero. Default
value is 5 minutes.
Alarm Relay Output
The alarm relay output is a configurable normally open 24- -VAC
output defaulted to relay 11 on the Main Base Board (MBB) TB2
connector. Selection of which alerts and faults will result in closing of
the alarm relay may be set in the Alarm Relay Configuration
(SETTINGS UNIT CONFIGURATIONSALARM RELAY).
Setting a configuration to YES will result in the alarm output relay to
energize when that particular condition is in an alarm state. Setting a
configuration to NO will result in no action by the alarm output relay
for that particular condition.
NOTE: An accessory filter switch can be used along with the
alarm relay output function to indicate dirty filter service need. See
the Troubleshooting section for more information on viewing,
diagnosing, and clearing alerts and alarms.

TROUBLESHOOTING

The SystemVut display shows actual operating conditions of the unit
while it is running. If there are alarms or there have been alarms, they
will be displayed in either the active faults, active alerts, or the history
alarm list (see Table 13 starting on page 34). Service Test mode allows
proper operation of the compressors, fans, and other components to be
checked while the unit is not operating. See Service Test (on page 11).
28
How Device is derived
Local display BACnet Id---BACNet
Writes not allowed
Device Id Prefix + Mac --- BACnet
writes allowed
Device Id Prefix + MAC (prefix updat-
ed by color cache) --- BACnet writes
not allowed
MAC
range
0---127
0---99
0---99