
Excel 10 W7751B,D,F VAV II Controllers
FEATURES
- Uses Echelon LonWorks® network (E-Bus) protocol.
- Free Topology Transceiver (FTT) high speed 78 kilobit
communications network.
- Compliant with VAV Device Object Type number 8010 functional
LonMark® profile.
- Capable of stand-alone operation, but can also use E-Bus
network communications.
- 120 controllers per Q7750A Excel 10 Zone Manager.
- Easy user access to the E-Bus network communications jack.
- Designed for Pressure Independent or Pressure Dependent
Single or Dual Duct Variable Air Volume (VAV) and
Constant Volume Air Terminal Unit control.
- Uses a Microbridge air flow sensor with patented dual
integral restrictor design.
- Easy user access to air flow sensor inputs.
- Provides Proportional Integral Derivative (PID) temperature
control.
- Energy saving setpoint reset for electrical demand limit
control.
- Floating or modulating hot water or three-stage electric
heat.
- Series or induction fan control.
- Provides patented nonlinear floating algorithm for velocity
control loops.
- Individual zone pressurization for supply and exhaust
control.
- Factory configured via EEPROM with critical user parameter
default values.
- Supports motion sensor interface for enhanced energy
savings.
- Supports Terminal Regulated Air Volume (TRAV) concept.
- Supports pressurize and depressurize, night purge, and
morning warm-up sequences.
- Both plastic housing and controller module wiring subbase
are UL 94-5V rated (W7751D,F).
GENERAL
The W7751B,D,F are Variable Air Volume (VAV) Controllers in
the Excel 10 family product line. These VAV systems provide pressure independent or
pressure dependent air flow control and series or induction fan control using single and
dual duct applications. VAV systems generally provide cool air only to the zones. The
W7751 controllers provide additional outputs that control VAV box reheat coils. The
heaters can be staged electric or modulating hot water. Supply and exhaust pressurization
control are provided on a zone basis.
DESCRIPTION
The W7751B,D,F are Variable Air Volume (VAV) Controllers in
the Excel 10 family product line. These VAV systems provide pressure independent or
pressure dependent air flow control and series or induction fan control using single and
dual duct applications. VAV systems generally provide cool air only to the zones. The
W7751 controllers provide additional outputs that control VAV box reheat coils. The
heaters can be staged electric or modulating hot water. Supply and exhaust pressurization
control are provided on a zone basis.
SPECIFICATIONS
Models
W7751B: The W7751B is implemented on a snap track
compatible Printed Wiring Board (PWB). Terminal blocks are used to make connections to the
digital input terminals (13 through 17) the wall module terminals (19 through 25) and the
communications terminals 29 and 30. Connection for access provided by plugging the
connector into the communications jack. Digital outputs, earth 24 Vac power connections
are made with (6.35 mm) quick connects.
W7751D: The W7751D uses a two-piece construction controller
module and an internally wired Field wiring 14 to 22 AWG (2.0 to 0.34 mm conduit, connects
to the terminal blocks on subbase. The controller module plugs into subbase.
W7751F: The W7751F uses a two-piece construction controller
module and an externally wired Field wiring 14 to 22 AWG (2.0 to 0.34 mm connected to the
terminal blocks on the top external edges of the subbase. The controller plugs into the
prewired subbase. See Table Control techniques supported.
Single Duct Applications: See Table 2.
| Heating and Cooling |
Fan |
Up to three stages of
electric or hot water heat
Floating hot water heat
Pulse Width Modulated (PWM) heat
Floating damper output |
no fan
induction fan (Parallel Temperature or Fan
(PWM Fan)
series fan (Series Fan) |
Other
Important Control Features |
Three setpoint
sets for heating and cooling.
OccupiedNormal hours or if bypass
invoked from wall module during unoccupied hours.
StandbyEnergy saving period during
occupied hours, invoked by motion detector.
UnoccupiedOff hours.
Supply, exhaust pressurization control are
provided on a zone basis. |
Table 2. Single Duct Application (Pressure Independent
| Damper Control Only |
| Damper Control, 1, 2, or 3 Stages Reheat |
| Damper Control, 1 Stage Peripheral Heat |
| Damper Control, Floating or PWM Reheat |
| Damper Control, Floating or PWM Peripheral
Reheat |
| Damper Control, Floating or PWM Reheat Plus
Floating or PWM Peripheral Heat* |
| Return Flow Tracking |
Staged Heat Options:
Reheat
Standard, stepped (1, 1 and 2, 1
and 2 and 3)
Binary (1, 2, 1 and 2)
Peripheral Heat
1 stage only |
Fan Options**:
Series
(Induction fan):
Parallel***
Temperature
Flow
PWM fan
None |
Modulating Heat Options (Reheat and
Peripheral)
Floating
Pulse Width Modulation (PWM) |
* If both Reheat and peripheral heat are used in the same
application:
Both must be same output type such that both are staged,
floating or staged PWM (all PWM actuators must use the same time-based mode parameters).
The first and second stage ordering is selectable between;
stage 1 - reheat, stage 2 peripheral or stage 1 - peripheral, stage 2 reheat
** All single duct applications support series fan,
(Induction fan): parallel temperature and fan flow or PWM
fan for operations or no fan.
NOTE: PWM fan actuator temperature controls just the
opposite of a VAV damper actuator such that an increase in air flow gives a decrease in
fan speed.
*** Parallel fan options: Standard - controlled by
temperature and acts as a form of reheat. Flow - adds return air from the plenum to ensure
minimum discharge flow.
Dual Duct Applications
See Table 3.
Input/Output:
See Tables 4 and 5.
Table 3. Dual Duct Applications
| These applications require two VAV
Controllers and two ML6161 direct-coupled damper actuators per zone |
| Dual Duct, Pressure Independent, with flow
mixing, with cold and hot duct flow pickups (uses a satellite Excel 10 for the hot duct) |
| Dual Duct, Pressure Independent, without flow
mixing, with cold and hot duct flow pickups (uses a satellite Excel 10 for the hot duct) |
| Dual Duct, Pressure Independent, constant
volume, with cold and hot duct flow pickups (uses a satellite Excel 10 for the hot duct) |
| These applications require
one VAV Controller and one or two ML6161 direct-coupled damper actuator per area supplied
by the VAV box |
| Dual Duct, Pressure Independent, with cold
duct pickup only |
| Dual Duct, Pressure Independent, constant
volume, with discharge pickup only, Flow sensor in discharge air. The temperature control
loop controls the cool damper position and the flow controls adjust the heating damper
position |
| Dual Duct, Pressure Independent, discharge
pickup, no mixing |
| Dual Duct, Pressure Dependent, with flow
mixing |
| Dual Duct, Pressure Dependent, without flow
mixing |
Table 4. VAV II Controller Inputs
Analog inputs -
4 total |
| Space temperature sensor (fixed location) -
T7770A,B,C,D or T7780A Digital Display Wall Module (DDWM) |
| Air flow pressure sensor (fixed location) -
Microbridge 0-2 inw (0 to 0.5 kPa) velocity pressure sensor |
Configurable analog input options (any two
unique items from the following)
Space temperature setpoint from T7770B,D 55 to 85°F (13 to 29.5°C) -
9846 to 1290 ohms
Discharge Air temperature sensor
Type RTD
Supported Sensors: C7770A1006,
C7031B1033, C7031C1031, C7031D1062, C7031F1018, C7031J1050, C7031K1017
Supply Air Temperature
Type RTD
Supported Sensors: C7770A1006,
C7031B1033, C7031C1031, C7031D1062, C7031F1018, C7031J1050, C7031K1017 |
Digital inputs -
5 total |
| Wall Module Bypass Pushbutton- Momentary DI
(fixed location) |
| Hardware test (fixed location) |
Configurable digital input options (up to
three unique items from following)
| Window open- (contact closed = window closed) |
| Occupancy switch- (contact closed = room
occupied; contact open = room unoccupied) |
| Heat/cool change over- (contact closed =
heat) |
| Monitoring input- ( contact closed = input on
or closed-reportable on network) |
|
Table 5. VAV II Controller
Digital outputs
| Configurable digital output options (8
total): |
| Floating damper open |
| Floating damper closed |
Reheat types:
| Reheat (floating) valve open |
| Reheat (floating) valve closed PWM** |
Three stage binary control:
| *Stage 1 (output 1) |
| *Stage 2 (output 2) |
| *Stage 3 (both outputs 1 and 2) |
|
| Fan
Series
(Induction fan):
Parallel
Temperature
Flow
PWM fan |
| Auxiliary contact (On when occupied, Off when
unoccupied or Standby)
Normal (On/Off digital)
Pulsed (requires one pair open and closed) |
| Network (up to 2 outputs commanded from the
network) Normal (On/Off
digital)
Pulsed (requires two outputs) |
| * Staged reheat coils are disabled if air
flow is less than one half of reheat air flow setpoint. ** All PWM actuators must use the same time-based mode parameters. |
Triac Outputs:
Power ratings: 20 Vac to 30 Vac at 25mA MIN to 500mA MAX
current for any voltage, W7751B has a MAX current of 400mA.
NOTE: Triacs sink current to the 24 Vac common (terminal 10
on the W7751B model or terminals 2 and 4 on the W7751D,F models. The controller and all
Triac loads must be wired to the same 24 Vac source.
IMPORTANT
If non-Honeywell motors, actuators, or transducers are to
be used with Excel 10 Controllers, Triac compatibility must be verified (see previous
NOTE).
Power Supply:
24 Vac with a valid range of 20 to 30 Vac at 50/60 Hz.
Power Consumption (no load):
10 VA maximum at both 50 and 60 Hz.
CPU:
Motorola or Toshiba 3150 Neuron® processor,
containing three eight bit CPUs. Each Neuron has a unique 48-bit network identification
number.
Memory Capacity:
The W7751B,D,F VAV Controllers uses a 64K by 8 ROM/PROM,
512 bytes of EEPROM and 2K of RAM.
Differential Pressure Range:
0 to 2.0 inw (0 to 0.5 kPa) maximum for the onboard flow
sensor.
Specified Sensing Temperature Range:
20 Kohm NTC sensor temperature range of 45 to 99°F (7 to
37°C) with an allowable control setpoint range from 50 to 90°F (10 to 32°C) when
initiated from the network and 55 to 85°F (13 to 29°C) when configured and connected to
a T7770, T7780A DDWM or C7770A Air temperature Sensor.

Communications:
The W7751 uses an FTT transformer-coupled communications
port with manchester encoded data being presented to controllers and devices on the E-Bus
at 78 kilobits per second (kbs) via Echelon® communication protocol. Using the
transformer-coupled communications interface offers a much higher degree of common
mode-noise rejection while assuring dc isolation. The E-Bus is insensitive to polarity,
eliminating installation errors due to miswiring.
The maximum E-Bus network length up to 5000 ft (1524m). For
E-Bus network lengths greater than 5000 ft (1524m),see form 74-2865 E-Bus Wiring
Guidelines.
The maximum number of nodes per E-Bus segment is 60.
Approved cable type for E-Bus communications wiring is
Level IV 22 AWG (0.34mm 2 ) plenum or nonplenum rated unshielded, twisted pair, solid
conductor wire.
LonMark® Functional Profile
W7751 Controllers support the LonMarkâ Functional Profile
number 8010 VAV Controller, version 1.0 (see Fig. 1).
Mounting Options:
The W7751B is a snaptrack compatible PWB. The W7751D
Subbase can be mounted to standard four by four inch and five by five inch junction boxes
and also be snapped to 35 by 7.5 mm (1-3/8 by 9/32 in.) EN 50 022 DIN rail. The W7751F
Subbase can be mounted in a ring cabinet or wall mounted and also be snapped to 35 by 7.5
mm (1-3/8 by 9/32 in.) EN 50 022 DIN rail. The W7751D,F Subbases provide the slotted hole
pattern for the R7450 series IRC devices (118 by 87 mm).

Dimensions (H/W/D):
W7751B: 3-1/4 x 9.0 in. (83 x 229 mm).
W7751D,F: 5-21/32 x 5-21/32 x 2-11/32 in. (144 x 144 x 60 mm).
Environmental Ratings:
Operating Temperature: 32 to 125°F (0 to 51.7°C).
Shipping Temperature: -40 to 150°F (-40 to 65.5°C).
Relative Humidity:
5% to 95% noncondensing.
Vibration:
Rated V2 Level compliant
Approval Bodies:
The W7751 is listed under UL 916 (E87741) and is also listed by cUL (E87741). The
W7751B,D,F models meet FCC part 15 class B requirements (the W7751B meets class B with a
ferrite clamp-on). Without the ferrite clamp-on the W7751B meets Class A requirements. The
W7751B must be enclosed in a metal cabinet to meet class A and B requirements. For
CE requirements the W7751B,D,F models meet CISPR22B (the W7751B meets CISPR22B with a
ferrite clamp-on and must be enclosed in a metal cabinet).
Accessories:
- Excel 10 T7770 Wall Modules.
- T7780A DDWM.
- Excel 10 C7770A Air Temperature Sensor.
- Excel 10 Q7750A FTT Zone Manager.
- Excel 10 Q7751A,B Router.
- Excel 10 Q7752A,B Serial Interface Adapter.
- Excel 10 Connector Cable 205979 from the Excel 10 Q7752A
Serial Interface Adapter to Excel 10 Controller or Wall Module.
- 209541B Excel 10 Termination Module.
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