Справочник Пользователя для Honeywell W7750A
EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER
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INDOOR AIR QUALITY (IAQ) OVERRIDE
The Excel 10 W7750 Controller supports an IAQ override
feature that upon detection of poor air quality in the space,
allows the economizer dampers to be opened above the
standard minimum position setting to a value set in
EconIAQPos. Two different methods of detecting poor air
quality are supported, The first is by using an IAQ switch
device connected to a digital input on the W7750 Controller,
where a contact closure indicates poor air quality and initiates
the IAQ override mode. The second, which is only available
on the W7750B,C is through an analog input that connects to
a CO
feature that upon detection of poor air quality in the space,
allows the economizer dampers to be opened above the
standard minimum position setting to a value set in
EconIAQPos. Two different methods of detecting poor air
quality are supported, The first is by using an IAQ switch
device connected to a digital input on the W7750 Controller,
where a contact closure indicates poor air quality and initiates
the IAQ override mode. The second, which is only available
on the W7750B,C is through an analog input that connects to
a CO
2
Sensor (0 to 10V). The measured value of CO
2
from
this sensor (0 to 2000 ppm) is compared to the setpoint
IAQSetpt. When the CO
IAQSetpt. When the CO
2
level is higher than the setpoint (800
PPM), the IAQ override is initiated. The IAQSetpt hysteresis is
50 PPM, IAQ override is deactivated at a CO
50 PPM, IAQ override is deactivated at a CO
2
level less than
750 PPM.
When the W7750 Controller is in the COOL mode during an
IAQ override, it is possible for the heating outputs to be
activated. This can occur if the outdoor air temperature is cold
enough to cause the discharge air temperature to drop below
the DaTempLoLim setpoint when the dampers open to the
EconIAQPos position, and the IaqUseHeat flag is set. If this
situation occurs, the heating is controlled to maintain the
discharge air temperature at 1°F (0.65°C) above the
DaTempLoLim setpoint.
IAQ override, it is possible for the heating outputs to be
activated. This can occur if the outdoor air temperature is cold
enough to cause the discharge air temperature to drop below
the DaTempLoLim setpoint when the dampers open to the
EconIAQPos position, and the IaqUseHeat flag is set. If this
situation occurs, the heating is controlled to maintain the
discharge air temperature at 1°F (0.65°C) above the
DaTempLoLim setpoint.
FREEZE STAT
Upon receiving a contact closure, the W7750 control
algorithm will close the outdoor air damper and open the hot
water and chilled water valves (if available) to the full open
position as a safety precaution. If manual-reset operation is
desired, the Freeze Stat device must provide the physical
pushbutton, which the operator presses, to reset the system
after a freeze condition has occurred.
algorithm will close the outdoor air damper and open the hot
water and chilled water valves (if available) to the full open
position as a safety precaution. If manual-reset operation is
desired, the Freeze Stat device must provide the physical
pushbutton, which the operator presses, to reset the system
after a freeze condition has occurred.
DISCHARGE AIR LOW LIMIT CONTROL
If the discharge air temperature falls below the user-settable
discharge air low limit setpoint (DaTempLoLim), an alarm is
issued, and the outdoor air damper is driven below the
minimum position setting until the discharge temperature is up
to the low limit. If necessary, the damper can go completely
closed even during Occupied mode operation. As the
discharge temperature warms up, the economizer modulates
open until the minimum position setting is reached. At this
point, the low limit alarm is cleared.
discharge air low limit setpoint (DaTempLoLim), an alarm is
issued, and the outdoor air damper is driven below the
minimum position setting until the discharge temperature is up
to the low limit. If necessary, the damper can go completely
closed even during Occupied mode operation. As the
discharge temperature warms up, the economizer modulates
open until the minimum position setting is reached. At this
point, the low limit alarm is cleared.
ECONOMIZER ENABLE/DISABLE CONTROL
The W7750 Controller has inputs to determine if the outdoor
air is suitable to augment cooling. The economizer dampers
can be enabled/disabled for using outdoor air as the first
stage of cooling based on one of ten allowable strategies:
air is suitable to augment cooling. The economizer dampers
can be enabled/disabled for using outdoor air as the first
stage of cooling based on one of ten allowable strategies:
1.
Digital Input Enable/Disable—contact closure enables
economizer.
economizer.
2.
Outdoor Temperature—when the outdoor temperature
is less than OaEconEnTemp, then the outdoor air is
suitable to augment cooling.
is less than OaEconEnTemp, then the outdoor air is
suitable to augment cooling.
3.
Outdoor Enthalpy, Type A—when the outdoor
enthalpy meets the H205 type A requirements, the
outdoor air is suitable to augment cooling.
enthalpy meets the H205 type A requirements, the
outdoor air is suitable to augment cooling.
4.
Outdoor Enthalpy, Type B—when the outdoor
enthalpy meets the H205 type B requirements, the
outdoor air is suitable to augment cooling.
enthalpy meets the H205 type B requirements, the
outdoor air is suitable to augment cooling.
5.
Outdoor Enthalpy, Type C—when the outdoor
enthalpy meets the H205 type C requirements, the
outdoor air is suitable to augment cooling.
enthalpy meets the H205 type C requirements, the
outdoor air is suitable to augment cooling.
6.
Outdoor Enthalpy, Type D—when the outdoor
enthalpy meets the H205 type D requirements, the
outdoor air is suitable to augment cooling.
enthalpy meets the H205 type D requirements, the
outdoor air is suitable to augment cooling.
7.
Differential Temperature—the difference between
outdoor temperature and return air temperature is
compared to DiffEconEnTemp to determine whether
outdoor air or return air is more suitable for use to
augment mechanical cooling.
outdoor temperature and return air temperature is
compared to DiffEconEnTemp to determine whether
outdoor air or return air is more suitable for use to
augment mechanical cooling.
8.
Single Calculated Enthalpy—the calculated outdoor
enthalpy in btu/lb is compared to the enthalpy setpoint
(OaEnthEn) in btu/lb, and the outdoor temperature is
compared to the outdoor temperature limit setpoint
(OaEconEnTemp) for a high limit. The compared
difference determines whether outdoor air is suitable for
use to augment mechanical cooling.
enthalpy in btu/lb is compared to the enthalpy setpoint
(OaEnthEn) in btu/lb, and the outdoor temperature is
compared to the outdoor temperature limit setpoint
(OaEconEnTemp) for a high limit. The compared
difference determines whether outdoor air is suitable for
use to augment mechanical cooling.
9.
Differential Enthalpy, Either Sensed or Calculated—
the difference between outdoor enthalpy and return air
enthalpy determines whether outdoor air or return air is
more suitable to augment mechanical cooling. When
enthalpy sensors are configured, they are used for
comparing enthalpy. If no enthalpy sensors are
available, then enthalpy is calculated using outdoor and
return air humidity and temperature sensors. The
switching differential is fixed at 1.0 mA for enthalpy
sensors, and 0.25 btu/lb for calculated enthalpy.
the difference between outdoor enthalpy and return air
enthalpy determines whether outdoor air or return air is
more suitable to augment mechanical cooling. When
enthalpy sensors are configured, they are used for
comparing enthalpy. If no enthalpy sensors are
available, then enthalpy is calculated using outdoor and
return air humidity and temperature sensors. The
switching differential is fixed at 1.0 mA for enthalpy
sensors, and 0.25 btu/lb for calculated enthalpy.
NOTE:
If no return temperature sensor is configured,
space temperature is used to calculate return
air enthalpy.
space temperature is used to calculate return
air enthalpy.
10.
Network Enabled—the network input DestEconEnable
controls the enabling and disabling of the economizer.
When using the network input, select Econo Enable
Type: No Economizer in E-Vision. The network input
has priority over the other nine economizer control
selections.
controls the enabling and disabling of the economizer.
When using the network input, select Econo Enable
Type: No Economizer in E-Vision. The network input
has priority over the other nine economizer control
selections.
Appendix C. Complete List of Excel 10
W7750 Controller User Addresses.
W7750 Controller User Addresses.
See Table 18 for W7750 Controller User Address table
numbers and point types.
numbers and point types.
The User Address Index following Table 18 lists the User
Addresses alphabetically and gives the page number where
the Address is located in each Table Number/Point Type.
Addresses alphabetically and gives the page number where
the Address is located in each Table Number/Point Type.
After Table 18 there is an alphabetical list of Mappable User
Addresses and Table Numbers. Following this is an
alphabetical list of Failure Detect User Addresses and Table
Numbers.
Addresses and Table Numbers. Following this is an
alphabetical list of Failure Detect User Addresses and Table
Numbers.
Table 18. Excel 10 W7750 Controller User
Address Point Types.
Table Number
Point Types
Table 20
Input/Output
Table 21
Control Parameters
Table 22
Energy Management Points
Table 23
Status Points
Table 24
Calibration Points
Table 25
Configuration Parameters
Table 26
L
ON
M
ARK
/Open System Points
Table 27
Direct Access and Special Manual Points
Table 28
Data Share Points