Справочник Пользователя для Honeywell W7750A
EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER
74-2958—1
52
Occasionally, the PID parameters require tuning to optimize
comfort and smooth equipment operation. This applies to the
W7750A,B,C Controllers.
comfort and smooth equipment operation. This applies to the
W7750A,B,C Controllers.
CVAHU Controllers are configured by E-Vision with default
values of PID parameters as shown in Appendix C Table 21. If
different values for these parameters are desired, Table 13
values of PID parameters as shown in Appendix C Table 21. If
different values for these parameters are desired, Table 13
lists some recommended values to use as a starting point.
These recommended values are based on past experience
with the applications and in most cases do not require further
adjustment.
These recommended values are based on past experience
with the applications and in most cases do not require further
adjustment.
Table 13. Recommended Values For PID Parameters.
If the PID parameters require adjustment away from these
values, use caution to ensure that equipment problems do not
arise (see CAUTION below). If any change to PID control
parameters is made, the adjustments should be gradual. After
each change, the system should be allowed to stabilize so the
effects of the change can be accurately observed. Then
further refinements can made, as needed, until the system is
operating as desired.
values, use caution to ensure that equipment problems do not
arise (see CAUTION below). If any change to PID control
parameters is made, the adjustments should be gradual. After
each change, the system should be allowed to stabilize so the
effects of the change can be accurately observed. Then
further refinements can made, as needed, until the system is
operating as desired.
CAUTION
If large or frequent changes to PID control parameters
are made, it is possible to cause equipment problems
such as short cycling compressors (if the stage
minimum run times were disabled in User Addresses
DisMinClTime or DisMinHtTime). Other problems that
can occur include wide swings in space temperature
and excessive overdriving of modulating outputs.
are made, it is possible to cause equipment problems
such as short cycling compressors (if the stage
minimum run times were disabled in User Addresses
DisMinClTime or DisMinHtTime). Other problems that
can occur include wide swings in space temperature
and excessive overdriving of modulating outputs.
If adjustment of PID parameters is required, use the following.
In the items that follow, the term, error, refers to the difference
between the measured space temperature and the current
actual space temperature setpoint.
In the items that follow, the term, error, refers to the difference
between the measured space temperature and the current
actual space temperature setpoint.
— The Proportional Gain (also called Throttling Range)
determines how much impact the error has on the output
signal. Decreasing the Proportional Gain amplifies the
effect of the error; that is, for a given error, a small
Proportional Gain causes a higher output signal value.
signal. Decreasing the Proportional Gain amplifies the
effect of the error; that is, for a given error, a small
Proportional Gain causes a higher output signal value.
— The Integral Gain (also called Integral Time) determines
how much impact the error-over-time has on the output
signal. Error-over-time has two components making up its
value: the amount of time the error exists; and the size of
the error. The higher the Integral Gain, the slower the
control response. In other words, a decrease in Integral
Gain causes a more rapid response in the output signal.
signal. Error-over-time has two components making up its
value: the amount of time the error exists; and the size of
the error. The higher the Integral Gain, the slower the
control response. In other words, a decrease in Integral
Gain causes a more rapid response in the output signal.
— The Derivative Gain (also called Derivative Time)
determines how much impact the error rate has on the
output signal. The error rate is how fast the error value is
changing. It can also be the direction the space
temperature is going, either toward or away from the
setpoint, and its speed—quickly or slowly. A decrease in
Derivative Gain causes a given error rate to have a larger
effect on the output signal.
output signal. The error rate is how fast the error value is
changing. It can also be the direction the space
temperature is going, either toward or away from the
setpoint, and its speed—quickly or slowly. A decrease in
Derivative Gain causes a given error rate to have a larger
effect on the output signal.
— The Control Band is used only for discharge temperature
control of modulating outputs, which includes controlling
the economizer dampers, and heating and cooling valves
using Cascade Control. The Control Band dictates the
span through which the discharge temperature must travel
to cause the output signal to go from fully closed to fully
open. Also, 10 percent of the Control Band value is the size
of the deadband around the setpoint where no actuator
motion occurs. For example, if controlling a cooling valve
with Cascade Control enabled and with the discharge
temperature within 0.1 X DaTempClCtrlBd of the discharge
setpoint, there is no change in the current valve position.
The smaller the Control Band, the more responsive the
control output. A larger Control Band causes more sluggish
control. Be careful not to set the Control Band too low and
cause large over or under shoots (hunting). This can
happen if the space or discharge sensors or wiring are in
noisy environments and the value reported to the controller
is not stable (such that it bounces). The Control Band is
used only in modulating control, and has no purpose when
staged control is configured.
the economizer dampers, and heating and cooling valves
using Cascade Control. The Control Band dictates the
span through which the discharge temperature must travel
to cause the output signal to go from fully closed to fully
open. Also, 10 percent of the Control Band value is the size
of the deadband around the setpoint where no actuator
motion occurs. For example, if controlling a cooling valve
with Cascade Control enabled and with the discharge
temperature within 0.1 X DaTempClCtrlBd of the discharge
setpoint, there is no change in the current valve position.
The smaller the Control Band, the more responsive the
control output. A larger Control Band causes more sluggish
control. Be careful not to set the Control Band too low and
cause large over or under shoots (hunting). This can
happen if the space or discharge sensors or wiring are in
noisy environments and the value reported to the controller
is not stable (such that it bounces). The Control Band is
used only in modulating control, and has no purpose when
staged control is configured.
Appendix B. Sequences of Operation.
This Appendix provides the control sequences of operation for
the models of the Excel 10 W7750 CVAHU Controller. The
W7750A,B,C Controllers can be configured to control a wide
variety of possible equipment arrangements. Table 14 and 15
(copied from Tables 3 and 4) summarize the available options.
This Appendix provides a more detailed discussion of these
options.
the models of the Excel 10 W7750 CVAHU Controller. The
W7750A,B,C Controllers can be configured to control a wide
variety of possible equipment arrangements. Table 14 and 15
(copied from Tables 3 and 4) summarize the available options.
This Appendix provides a more detailed discussion of these
options.
Equipment Configuration
Heat
Prop.
Gain
Heat
Integ.
Gain
Integ.
Gain
Heat
Deriv.
Gain
Deriv.
Gain
Heat
Control
Band
Control
Band
Cool
Prop.
Gain
Prop.
Gain
Cool
Integ.
Gain
Integ.
Gain
Cool
Deriv.
Gain
Deriv.
Gain
Cool
Control
Band
Control
Band
Econ
Control
Band
Control
Band
Single Stage
2
3000
0
10
2
3000
0
10
10
Two Stages
3
2000
0
10
3
2000
0
10
10
Three Stages
4.5
1500
0
10
4.5
1500
0
10
10
Four Stages
6
1000
0
10
6
1000
0
10
10
Series 60 Modulating (Floating)
2
750
0
10
2
750
0
10
10
PWM Modulating
2
900
0
10
2
900
0
10
10