Honeywell W7750A User Manual
EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER
74-2958—1
26
available through Honeywell, or directly from the
manufacturer, Mamac Systems (see Table 11 for ordering
information).
manufacturer, Mamac Systems (see Table 11 for ordering
information).
Fig. 17 depicts a typical W7750 System with modulating
heating valve using a pneumatic valve actuator. Also see Fig.
36 for wiring an MMC325 Pneumatic Transducer to a
W7750A,B,C Controller and Fig. 37 for wiring a RP7517B
Pneumatic Transducer to a W7750C Controller.
heating valve using a pneumatic valve actuator. Also see Fig.
36 for wiring an MMC325 Pneumatic Transducer to a
W7750A,B,C Controller and Fig. 37 for wiring a RP7517B
Pneumatic Transducer to a W7750C Controller.
NOTE:
When choosing the pneumatic pressure range, make
sure that the close-off pressure is 2 to 3 psi greater
than that of the spring range. When using a spring
range of 5 to 10 psi with 10 psi as the closed posi-
tion, do not use the 0 to 10 psi model of the MMC325
Transducer; use the 0 to 20 psi transducer as the
recommended selection.
sure that the close-off pressure is 2 to 3 psi greater
than that of the spring range. When using a spring
range of 5 to 10 psi with 10 psi as the closed posi-
tion, do not use the 0 to 10 psi model of the MMC325
Transducer; use the 0 to 20 psi transducer as the
recommended selection.
Fig. 17. Modulating heat with pneumatic valve actuator.
MIXED-OUTPUT-TYPE CONTROL
The W7750B,C Controller provides control for mixed-output-
types of applications such as PWM heating and staged
cooling control occurring simultaneously with Series 60
Floating Economizer Damper Control.
types of applications such as PWM heating and staged
cooling control occurring simultaneously with Series 60
Floating Economizer Damper Control.
Occupancy Sensor
Excel 10 W7750 Controllers provide a digital input for
connection to an occupancy sensor. This is a device, such as
a passive infrared motion detector, that contains a dry contact
(see following NOTE) closure to indicate whether or not
people are present in the space. The Excel 10 W7750
Controller expects a contact closure to indicate the space is
Occupied. See Fig. 27 through 35 in Application Step 4,
Prepare Wiring Diagrams, for details on wiring connections.
connection to an occupancy sensor. This is a device, such as
a passive infrared motion detector, that contains a dry contact
(see following NOTE) closure to indicate whether or not
people are present in the space. The Excel 10 W7750
Controller expects a contact closure to indicate the space is
Occupied. See Fig. 27 through 35 in Application Step 4,
Prepare Wiring Diagrams, for details on wiring connections.
The control algorithm in the Excel 10 Controller uses the
occupancy sensor, if configured, to determine the Effective
Occupancy (see Table 5) mode of operation. If the Time Of
Day (TOD) schedule indicates an Occupied state, and the
occupancy sensor contact is closed, the Effective Occupancy
mode is Occupied. However, if the TOD schedule indicates an
Occupied state and the occupancy sensor contact is open,
occupancy sensor, if configured, to determine the Effective
Occupancy (see Table 5) mode of operation. If the Time Of
Day (TOD) schedule indicates an Occupied state, and the
occupancy sensor contact is closed, the Effective Occupancy
mode is Occupied. However, if the TOD schedule indicates an
Occupied state and the occupancy sensor contact is open,
then the Effective Occupancy mode is STANDBY. The
temperature control algorithm is then controlled to the
STANDBY Cooling and Heating Setpoints.
temperature control algorithm is then controlled to the
STANDBY Cooling and Heating Setpoints.
If the occupancy sensor is not configured, a local controller
can be put in the STANDBY mode only by either a one-to-one
association of the occupancy sensor from another Excel 10
Controller to the local controller, or by receiving the STANDBY
mode signal via the L
can be put in the STANDBY mode only by either a one-to-one
association of the occupancy sensor from another Excel 10
Controller to the local controller, or by receiving the STANDBY
mode signal via the L
ON
W
ORKS
Bus.
NOTE:
The Excel 10 Controller has limited power available
(only 9 mA at 4.8 volts) for checking the digital inputs
for contact closures. It is very important that the
device used contains high quality, noncorroding
contacts with resistivity that does not degrade; that
is, increase over time. Use noble metal (such as gold
or silver), or pimpled or sealed contacts to assure
consistent, long-term operation.
(only 9 mA at 4.8 volts) for checking the digital inputs
for contact closures. It is very important that the
device used contains high quality, noncorroding
contacts with resistivity that does not degrade; that
is, increase over time. Use noble metal (such as gold
or silver), or pimpled or sealed contacts to assure
consistent, long-term operation.
The recommended devices for use with the Excel 10 W7750
Controllers are the EL7628A1007 Ceiling Mounted Infrared or
the EL7680A1008 Wall Mounted Wide View Infrared
Occupancy Sensors. If ultrasonic sensors are required, the
EL7611A1003 and the EL7612A1001 Occupancy Sensors are
recommended. An EL76XX Power Supply/Control Unit is
required for use with these occupancy sensors. The
EL7630A1003 can power up to four sensors, and is multi-
tapped for several line voltages. The EL7621A1002 can
power three sensors and it connects to 120 Vac line voltage.
The EL7621A1010 can also power three sensors but it
connects to 277 Vac line voltage.
Controllers are the EL7628A1007 Ceiling Mounted Infrared or
the EL7680A1008 Wall Mounted Wide View Infrared
Occupancy Sensors. If ultrasonic sensors are required, the
EL7611A1003 and the EL7612A1001 Occupancy Sensors are
recommended. An EL76XX Power Supply/Control Unit is
required for use with these occupancy sensors. The
EL7630A1003 can power up to four sensors, and is multi-
tapped for several line voltages. The EL7621A1002 can
power three sensors and it connects to 120 Vac line voltage.
The EL7621A1010 can also power three sensors but it
connects to 277 Vac line voltage.
Window Open/Closed Digital Input
A digital input is also provided for detecting whether a window
in the space was opened. The Excel 10 W7750 Controller can
be connected to a dry contact (see the following NOTE and
Fig. 27 through 35 in Application Step 4. Prepare Wiring
Diagrams, for details) or a set of contacts wired in series (for
monitoring multiple windows) to verify that the window(s) are
closed. The algorithm expects a contact closure to indicate
the window is closed. If an open window is detected, the
algorithm changes the mode of operation to
FREEZE_PROTECT, which shuts down the control functions,
and watches for low space temperature conditions. The frost
protection setpoint is 46.4
in the space was opened. The Excel 10 W7750 Controller can
be connected to a dry contact (see the following NOTE and
Fig. 27 through 35 in Application Step 4. Prepare Wiring
Diagrams, for details) or a set of contacts wired in series (for
monitoring multiple windows) to verify that the window(s) are
closed. The algorithm expects a contact closure to indicate
the window is closed. If an open window is detected, the
algorithm changes the mode of operation to
FREEZE_PROTECT, which shuts down the control functions,
and watches for low space temperature conditions. The frost
protection setpoint is 46.4
°
F (8
°
C), and the frost alarm occurs
at 42.8
°
F (6
°
C).
NOTE:
(This is the same NOTE as in the Occupancy Sensor
section.) The Excel 10 has limited power available
(only 9 mA at 4.8 volts) for checking the digital inputs
for contact closures. It is very important that the
device used contains high quality, noncorroding
contacts with resistivity that does not degrade; that
is, increase over time. Use noble metal (such as gold
or silver), or pimpled or sealed contacts to assure
consistent, long-term operation.
section.) The Excel 10 has limited power available
(only 9 mA at 4.8 volts) for checking the digital inputs
for contact closures. It is very important that the
device used contains high quality, noncorroding
contacts with resistivity that does not degrade; that
is, increase over time. Use noble metal (such as gold
or silver), or pimpled or sealed contacts to assure
consistent, long-term operation.
Wall Module Options
As previously discussed, there are four basic varieties of the
T7770 Wall Modules and two of the T7560 Digital Wall Module
(see the Product Names and the Construction sections). Also,
a T7770 and T7560 Wall Modules can be shared among two
or more W7750s. The control algorithm must be given this
wall module information when configuring the W7750 (see
Excel E-Vision User’s Guide, form 74-2588).
T7770 Wall Modules and two of the T7560 Digital Wall Module
(see the Product Names and the Construction sections). Also,
a T7770 and T7560 Wall Modules can be shared among two
or more W7750s. The control algorithm must be given this
wall module information when configuring the W7750 (see
Excel E-Vision User’s Guide, form 74-2588).
VALVE
PNEUMATIC
ACTUATOR
ACTUATOR
PNEUMATIC
TRANSDUCER
TRANSDUCER
MMC325
M
1
1
PNEUMATIC MAIN OR BRANCH LINE MUST BE 1/4 IN. (6 MM)
OR LARGER TUBING. A MINIMUM OF 6 FT (1.8M) OF TUBING
IS NEEDED IN A BRANCH LINE.
OR LARGER TUBING. A MINIMUM OF 6 FT (1.8M) OF TUBING
IS NEEDED IN A BRANCH LINE.
MIXED
AIR
AIR
HEAT
COIL
COIL
DISCHARGE
AIR
AIR
+
FAN
FAN
STARTER
M17495
T7560A,B OR T7770