Honeywell W7750A Manual De Usuario
EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER
74-2958—1
58
Fig. 47. Setpoint ramping parameters with setpoint
calculation.
During the COOL recovery period, the setpoint changes at a
rate in degrees per hour relative to the outdoor air
temperature. If there is no outdoor air temperature sensor
available, the MinClRamp is used as the recovery rate.
rate in degrees per hour relative to the outdoor air
temperature. If there is no outdoor air temperature sensor
available, the MinClRamp is used as the recovery rate.
See Fig. 48 for the various setpoints.
Fig. 48. Setpoint ramping parameters with ramp rate
calculation.
NOTES: The setpoint used during the COOL recovery period
is similar to the heat mode in Fig. 46, except the
slope of the line reverses for cooling.
slope of the line reverses for cooling.
Recovery ramping applies between scheduled heat-
ing or cooling setpoint changes from UNOCCUPIED
to STANDBY, UNOCCUPIED to OCCUPIED, and
STANDBY to OCCUPIED. Scheduled setpoint
changes from OCCUPIED to UNOCCUPIED or
OCCUPIED to STANDBY do not use a ramped set-
point, but instead, use a step change in setpoint.
Recovery ramps begin before the next scheduled
occupancy time and are ramped from the setpoint for
the existing scheduled occupancy state to the set-
point for the next occupancy state.
ing or cooling setpoint changes from UNOCCUPIED
to STANDBY, UNOCCUPIED to OCCUPIED, and
STANDBY to OCCUPIED. Scheduled setpoint
changes from OCCUPIED to UNOCCUPIED or
OCCUPIED to STANDBY do not use a ramped set-
point, but instead, use a step change in setpoint.
Recovery ramps begin before the next scheduled
occupancy time and are ramped from the setpoint for
the existing scheduled occupancy state to the set-
point for the next occupancy state.
FAN OPERATION
The W7750 supply fan can be controlled in one of two
different ways. In Continuous Fan mode, the fan runs
whenever the controller is in Occupied mode. When in
different ways. In Continuous Fan mode, the fan runs
whenever the controller is in Occupied mode. When in
Standby or Unoccupied modes, the fan cycles on with a call
for cooling (or heating if the FanOnHtMode parameter is set).
In Intermittent Fan mode, the fan cycles on with a call for
cooling (or heating if the FanOnHtMode parameter is set), and
cycles off when the space temperature control is satisfied.
for cooling (or heating if the FanOnHtMode parameter is set).
In Intermittent Fan mode, the fan cycles on with a call for
cooling (or heating if the FanOnHtMode parameter is set), and
cycles off when the space temperature control is satisfied.
The fan control supports an optional (Proof of Air Flow) digital
input, that allows monitoring of the supply fans status. If the
fan is commanded on, the Proof of Air Flow digital input is
checked up to three times to verify that the fan is running after
an initial delay of FanOnDelay seconds (user-settable). If the
fan fails to start the CVAHU must be reset by first cycling
CVAHU power. If this does not work, set DestManMode to
Manual and then back to Enable. After a reset the application
restarts—all outputs switch off and auto control is enabled.
input, that allows monitoring of the supply fans status. If the
fan is commanded on, the Proof of Air Flow digital input is
checked up to three times to verify that the fan is running after
an initial delay of FanOnDelay seconds (user-settable). If the
fan fails to start the CVAHU must be reset by first cycling
CVAHU power. If this does not work, set DestManMode to
Manual and then back to Enable. After a reset the application
restarts—all outputs switch off and auto control is enabled.
Also, the W7750 Controller provides fan-run-on operation that
keeps the fan running for a short time after heating or cooling
shuts off. The amount of time that the fan continues to run is
set in FanRunOnHeat for heating mode and FanRunOnCool
for cooling mode.
keeps the fan running for a short time after heating or cooling
shuts off. The amount of time that the fan continues to run is
set in FanRunOnHeat for heating mode and FanRunOnCool
for cooling mode.
WINDOW SENSOR (StatusWndw)
The digital input for a window contact provides the algorithm
with a means to disable its temperature control activities if
someone has opened a window or door in the room. When a
window is detected to be Open (digital input contacts Open
equals window open), the normal temperature control is
disabled, and the W7750 Controller enters the Freeze Protect
mode. Freeze Protect mode sets the space setpoint to 46.4 °F
(8°C) and brings on the fan and heat if the space temperature
falls below this setpoint. Normal temperature control resumes
on window closure. The Window sensor signal can also be a
network input from another L
with a means to disable its temperature control activities if
someone has opened a window or door in the room. When a
window is detected to be Open (digital input contacts Open
equals window open), the normal temperature control is
disabled, and the W7750 Controller enters the Freeze Protect
mode. Freeze Protect mode sets the space setpoint to 46.4 °F
(8°C) and brings on the fan and heat if the space temperature
falls below this setpoint. Normal temperature control resumes
on window closure. The Window 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.
SMOKE CONTROL
The Excel 10 W7750 Controller supports three smoke-related
control strategies:
control strategies:
1.
Emergency Shutdown (all outputs off).
2.
Depressurize (fan on, outdoor air damper closed).
3.
Pressurize (fan on, outdoor air damper open).
The controller is placed in one of these three control states
whenever the W7750 mode becomes
SMOKE_EMERGENCY, which can be initiated via a network
command (DestEmergCmd) or from a local (physically
connected) smoke detector digital input. When in
SMOKE_EMERGENCY mode, the W7750 Controller uses the
control strategy found in SmkCtlMode (one of the three listed
above), and the normal temperature control function is
disabled. If a W7750 local smoke detector trips, the SrcEmerg
network variable (for other L
whenever the W7750 mode becomes
SMOKE_EMERGENCY, which can be initiated via a network
command (DestEmergCmd) or from a local (physically
connected) smoke detector digital input. When in
SMOKE_EMERGENCY mode, the W7750 Controller uses the
control strategy found in SmkCtlMode (one of the three listed
above), and the normal temperature control function is
disabled. If a W7750 local smoke detector trips, the SrcEmerg
network variable (for other L
ON
W
ORKS
Bus devices to receive)
is set to the Emergency state.
DEMAND LIMIT CONTROL (DLC)
When The L
ON
W
ORKS
Bus network receives a high-electrical-
demand signal, the controller applies a DlcBumpTemp amount
to the current actual space temperature setpoint value. The
setpoint is always adjusted in the energy-saving direction.
This means that if the W7750 Controller is in Cooling mode,
the DLC offset bumps the control point up, and when in
Heating mode, bumps the control point down.
to the current actual space temperature setpoint value. The
setpoint is always adjusted in the energy-saving direction.
This means that if the W7750 Controller is in Cooling mode,
the DLC offset bumps the control point up, and when in
Heating mode, bumps the control point down.
OCC setpoint
UN_OCC setpoint
OR
STANDBY setpoint
M10110
AUX HEAT
SETPOINT
SETPOINT
HEAT PUMP
SETPOINT
(FOR COMPRESSORS)
SETPOINT
(FOR COMPRESSORS)
RECOVERY TIME
OCCUPIED TIME
COOL RECOVERY
RAMP RATE
(DEGREES/HOUR)
RAMP RATE
(DEGREES/HOUR)
MaxClRam
MinClRam
OaTempMinClRa
OaTempMaxClRam
OUTDOOR AIR
TEMPERATURE
TEMPERATURE
M10111