32
BACnet Network Operation
The SystemVu™ 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 de-
fault setting is BACnet and the Default BACnet Baud rate is
76800. These setting are found on the SETTINGS NET-
WORK 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 Table 15 for
assistance.
Before connecting to the BACnet system, determine the sys-
tem requirements and use the following guide to configure the
BACnet settings. Then power the controller down, connect to
the BACnet MS/TP network, and locate the controller.
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 control-
ler from 0 to 99 and then power down and connect to the net-
work. The router will find and send the network number to the
controller and the controller will set it device ID with the net-
work 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 be-
fore. Then connect to the network and write the device ID to
the controller at the MAC address previously set. The control-
ler 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.
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 signify a warning of some sort or the im-
properly functioning circuit can restart without human interac-
tion. 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 re-
set 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 proper-
ly 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 shut-
down fault for that particular circuit. Once activated, the shut-
down fault can only be cleared via an alarm reset.
However, circuits with strikes will be given an opportunity to
reset 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 count-
er 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 CONFIGURA-
TIONS ALARM RELAY). Setting a configuration to YES
will result in the alarm output relay to energize when that par-
ticular 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 SystemVu™ 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 16 starting on
page 38). 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 12.
Complete Unit Stoppage
There are several conditions that can cause a complete unit
stoppage, including:
• A fault is active which causes the unit to shut down.
• Cooling and heating loads are satisfied.
• Programmed occupancy schedule.
• General power failure.
• Tripped 24-volt transformer circuit breakers.
•Blown fuse or circuit breakers
• Unit is turned off through the network.
Restart Procedure
Before attempting to restart the machine, check the faults and
alerts list to determine the cause of the shut down. If the shut-
down fault for a particular control function has occurred, deter-
mine and correct the cause before allowing the unit to run un-
der its own control again. When there is a problem, the unit
should be diagnosed in Service Test mode. The faults must be
reset before the control function can operate in either Normal
mode or Service Test mode.
Faults and Alerts
VIEWING AND CLEARING UNIT ALARMS
Presence of active alarms will be indicated on the SystemVu
display by the Alarm Status lights. When alerts are active, the
yellow “ALERT” light will be lit. When faults are active, the
red “FAULT” light will be lit. When the unit is operational,
then green “RUN” light will be lit. The SystemVu controller
standby screen will be updated with the active alarms for easy
access. Presence of active alarms may also be signaled on the
Alarm Output terminals. Each alarm may also be broadcast on
the CCN network. Active alarms and past alarm history can be
reviewed and cleared via the local display or a network device.
The following menu locations are used for the local display.
Table 15 — BACnet and i-Vu Settings
BACNET ID
AUTO/
MANUAL
i-VU AUTO
SCHEME
HOW DEVICE
IS DERIVED
MAC
RANGE
Manual ON or OFF
Local display BACnet ID-BACNet
writes not allowed
0-127
Auto OFF
Device ID Prefix + Mac - BACnet
writes allowed
0-99
Auto ON
Device ID Prefix + MAC (prefix
updated by color cache) - BACnet
writes not allowed
0-99
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