Function Blocks
Function Block Reference Guide
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2.15 CARB Function Block,
continued
Configuration Parameters,
continued
Table 2-11 General Tab Configuration Parameters
Properties Group
Parameter
Index#
Parameter Description
Value or Selection
Block
Order
N/A
Execution Order
Read Only. See “Configure’ Menu,
”Execution Order” to change.
Tag Name
8 character tag name
Descriptor
Block Desriptor
Control
Algorithm
N/A
Control Algorithm
Note: In PID B, step
changes in setpoint will
not bump the output;
the output will slew
tosmoothly to the new
value.
In PID A, a step change
in setpoint will result in
a step change in output
.
PID A
- is normally used for 3
mode control. The output can
be adjusted somewhere
between 100% and 0%. It
applies all three control
actions -Proportional(P),
Integral(I), and Derivative(D) -
to the error signal.
PID B
- Unlike the PID-A
equation, the controller gives
only an integral response to a
setpoint change, with no
effect on the output due to the
Gain or Rate action, and
gives full response to PV
changes.
DUPA -
like PIDA but
provides an automatic
method to switch tuning
constant sets for Heat/Cool
applications.
DUPB -
like PIDB but
provides an automatic
method to switch tuning
constant sets for Heat/Cool
applications.
ATTENTION
With PID B
or DUPB selection, you
will
not
be allowed to set
RESETor RPM to 0.00 (OFF).
Reset must be enabled.
Direction
N/A
Control Action
DIRECT
- PID action causes
output to
increase
as process
variable increases.
REVERSE
- PID action
causes output to
decrease
as
process variable increases.
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