Instruction Manual

Data Structures and Expressions
A-4
Tags assigned by the firmware, their data types, and their descriptions are listed in a
Table A1.
Reserved Tags
Tag Data
Type
Description
ACTIVE_FLG Boolean
This controller is controlling the process. It is not a reserve
controller.
BIAS Real Bias auxiliary for PID ratio and bias subfunctions.
CD Real
Derivative gain as calculated so far during this scan. It is
initialized at the start of each scan from the loop auxiliary
CRATE.
CGAIN Real Loop proportional gain auxiliary.
CI Real
Integral gain as calculated so far during this scan. It is
initialized at the start of each scan from the loop auxiliary
CGAIN.
CP Real
Proportional gain as calculated so far during this scan. It is
initialized at the start of each scan from the loop auxiliary
CGAIN.
CRATE Real Loop derivative gain auxiliary.
CRESET Real Loop integral gain auxiliary.
DEV Real Loop deviation auxiliary.
HOLD-TIME Real,
Minutes
Length of time the sequence control function is held in
the current batch state.
(FNC #40)
H_FLG Boolean
Horn flag. This Boolean is set true whenever an alarm
becomes active and is reset to false when the acknowledge
button is pressed. It may also be set to false by the user's
configuration.
LOCAL_ONLY Boolean
When true, host write-tag commands are rejected unless
"local" is true (in the command). Note: the host must have
"local" on to turn LOCAL_ONLY off. This tag may be
controlled by the LOI to prevent inadvertent updates by the
central operator.
MANUAL-RESET Real
Manual reset as calculated so far during this scan. It is