Pid Control - Honeywell CVL4022ASVAV1 Engineering Manual

SHARE WALL MODULE
An example of sharing wall modules between three VAV
controllers (Wall Module is hard-wired to Controller 1 in the
figure) is shown in Fig. 33. To configure Exhaust Tracking Flow
Control Application in the tool, follow the configurations shown
below (see "Flow balancing" on page 34 for more information
on parameters).
Flow Type
Selected in the
Controller tool
1 FlowNormal
2 Share wall
module
3 Share wall
module
4 Share wall
module
Additionally, Bind nvoShare of VAV number 1, as Source
controller, to the nviShare of VAV number 2 through VAV
number 4, as the Destination controller.
ACCESSORY LOOPS
The AscLon VAV Controller can be configured with up to 2
accessory loops that are used to command outputs based on
an input variable. These loops have many built in features
enabling them to command a wide variety of applications.
31-00083—02
COLD
DUCT
SUPPLY
AIR
FLOW
DISCHARGE
SENSOR
AIR
1 1 1 1 1 1 1 2 2 2 2 2
CVL
3 4 5 6 7 8 9 0 1 2 3 4
CONTROLLER
nvoFLOW
NUMBER 1
TRACK
1 1
1 2 3 4 5 6 7 8 9 0 1 2
FLOW
SENSOR DISCHARGE
AIR
nvoFLOW
TRACK 1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
nvoFLOW
1 1
1 2 3 4 5 6 7 8 9 0 1 2
TRACK
FLOW
DISCHARGE
SENSOR
AIR
1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
CVL
CONTROLLER
nvoFLOW
NUMBER 3
TRACK
1 1
1 2 3 4 5 6 7 8 9 0 1 2
nvoFLOW
TRACK
Fig. 33. Exhaust Tracking Flow Control.
Box Type
Selected in Wall Module
the tool Type
Single Duct Conventional/
TR71-75
Single Duct No Sensor
Single Duct No Sensor
Single Duct No Sensor
T7770
70
SPACE
AIR
TEMP
T7770
FLOW
SENSOR
70
SPACE 1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
CVL
AIR
CONTROLLER
TEMP
NUMBER 2
1 1
1 2 3 4 5 6 7 8 9 0 1 2
T7770
nvoFLOW
TRACK
70
SPACE
AIR
TEMP
The fundamental operation of a control loop compares the
value of the input sensor (measured variable) to the setpoint
and calculates the output using the PID parameters.
Each control loop can configure the primary output as analog
or staged (1 to 3 stages). Each control loop also has an
auxiliary DO for controlling a fan or a pump. Configured
accessory loops run once per second.

PID CONTROL

The actual PID control algorithm is more complex, but can be
explained as follows where:
O = Control signal output. V = Calculated output.
M = Output Bias.
Ep = Proportional Error.
Ep-1 = Ep from the previous iteration. Ei = Integral Error.
Ed = Derivative Error.
Sen = Input sensor value.
SP = Setpoint.
TR = Throttling Range. Ti = Integral Time.
Td = Derivative Time.
O = If (V x 100% + M) < 0% Then 0%
28
EXHAUST
AIR
CVL
CONTROLLER
NUMBER 1
M33872