Honeywell W7750A User Manual
EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER
74-2958—1
56
Fig. 45. LED and Bypass pushbutton operation.
STANDBY MODE (StatusOcySen)
The digital input for an occupancy sensor (usually a motion
detector or possibly a time clock) provides the controller with a
means to enter an energy-saving Standby mode whenever
people are not in the room. Standby mode occurs when the
scheduled occupancy is Occupied, and the occupancy sensor
detects no people currently in the room (digital input contacts
Closed means people are in the room, and contacts Open
means the room is Unoccupied). When in Standby mode, the
Excel 10 W7750 Controller uses the Standby Cooling Setpoint
for cooling (CoolStbySpt), or the Standby Heating Setpoint for
Heating (HeatStbySpt) as the Actual Space Temperature
Setpoint. The occupancy sensor signal can also be a network
input from another L
detector or possibly a time clock) provides the controller with a
means to enter an energy-saving Standby mode whenever
people are not in the room. Standby mode occurs when the
scheduled occupancy is Occupied, and the occupancy sensor
detects no people currently in the room (digital input contacts
Closed means people are in the room, and contacts Open
means the room is Unoccupied). When in Standby mode, the
Excel 10 W7750 Controller uses the Standby Cooling Setpoint
for cooling (CoolStbySpt), or the Standby Heating Setpoint for
Heating (HeatStbySpt) as the Actual Space Temperature
Setpoint. The occupancy sensor signal can also be a network
input from another L
ON
W
ORKS
Bus device, so that no physical
sensor is required at the receiving W7750 Controller.
IMPORTANT
When the W7750 Controller is in Standby mode, the
economizer minimum position setting is not
observed. This means the fresh air dampers will go
fully closed if there is no call for cooling.
economizer minimum position setting is not
observed. This means the fresh air dampers will go
fully closed if there is no call for cooling.
CONTINUOUS UNOCCUPIED MODE
This mode is entered when a wall module is configured with a
Bypass pushbutton that was pressed for four to seven
seconds causing the wall module LED/LCD to blink. This
mode can also be entered via a network command
(ManualOcc set to Unoccupied). If the controller is in this
mode, it reverts to the Unoccupied setpoints for temperature
control, and the economizer does not observe its minimum
position setting. The controller remains in this mode
indefinitely until the Bypass pushbutton is pressed to exit the
mode or a network command is sent to clear the mode. A
configuration parameter is available to disable wall-module
initiation of Continuous Unoccupied mode (OvrdType).
Bypass pushbutton that was pressed for four to seven
seconds causing the wall module LED/LCD to blink. This
mode can also be entered via a network command
(ManualOcc set to Unoccupied). If the controller is in this
mode, it reverts to the Unoccupied setpoints for temperature
control, and the economizer does not observe its minimum
position setting. The controller remains in this mode
indefinitely until the Bypass pushbutton is pressed to exit the
mode or a network command is sent to clear the mode. A
configuration parameter is available to disable wall-module
initiation of Continuous Unoccupied mode (OvrdType).
OCCUPANCY MODE AND MANUAL OVERRIDE ARBITRATION
The W7750 has multiple sources for occupancy schedule
information and, therefore, it employs an arbitration scheme to
determine the current actual mode. Time-of-day (TOD)
schedule status comes from two sources, a configured digital
input for OccTimeClock or the DestSchedOcc network input
received from a central control. If the digital input source is
configured, it has highest priority and determines the
Occupancy mode. This digital input is either ON (shorted =
occupied), OFF (open = unoccupied), or not active (not
configured); otherwise, the status is determined by the
DestSchedOcc input from the network source. The
DestSchedOcc has three possible states, occupied,
unoccupied or standby.
information and, therefore, it employs an arbitration scheme to
determine the current actual mode. Time-of-day (TOD)
schedule status comes from two sources, a configured digital
input for OccTimeClock or the DestSchedOcc network input
received from a central control. If the digital input source is
configured, it has highest priority and determines the
Occupancy mode. This digital input is either ON (shorted =
occupied), OFF (open = unoccupied), or not active (not
configured); otherwise, the status is determined by the
DestSchedOcc input from the network source. The
DestSchedOcc has three possible states, occupied,
unoccupied or standby.
Manual Override Status can be derived from three sources
and governed by two selectable arbitration schemes. The two
schemes are:
•
and governed by two selectable arbitration schemes. The two
schemes are:
•
Network Wins or Last-in Wins, as set in OvrdPriority.
The three sources of manual override status are:
DestManOcc -
Has possible states: Occupied,
Unoccupied, Bypass, Standby and Not
Assigned (not active). This input source
has the highest priority in determining
manual override status for a Network
Wins arbitration scheme, and in the
event there is more than one source
change at a time in the Last-in Wins
arbitration scheme. Here, bypass
initiates a self-timed bypass of the
control unit and expires upon
completion of the defined timed period.
The controller then treats the bypass
status of this input as Not Assigned until
the next change in status.
Unoccupied, Bypass, Standby and Not
Assigned (not active). This input source
has the highest priority in determining
manual override status for a Network
Wins arbitration scheme, and in the
event there is more than one source
change at a time in the Last-in Wins
arbitration scheme. Here, bypass
initiates a self-timed bypass of the
control unit and expires upon
completion of the defined timed period.
The controller then treats the bypass
status of this input as Not Assigned until
the next change in status.
M8483A
RESET
NOT ASSIGNED
(LED OFF)
PRESS FOR ONE
TO FOUR SECONDS
TO FOUR SECONDS
BYPASS OCCUPIED
(LED ON)
BYPASS
TIMEOUT
TIMEOUT
PRESS FOR FOUR
TO SEVEN SECONDS
TO SEVEN SECONDS
PRESS FOR LESS
THAN ONE SECOND
THAN ONE SECOND
UNOCCUPIED
(LED BLINK)
PRESS FOR LESS THAN ONE SECOND
PRESS FOR MORE THAN SEVEN SECONDS