Table 4-10 Loop Prompts - Honeywell VRX180 User Manual

Programming Function Blocks and Features
Loop Menu Items
Table 4-10 alphabetically describes every loop menu item. See Table 4-2 for additional prompts.
Prompt
APPROACH HIGH
APPROACH LOW
AUTO/MAN SELECT
CHG ACTION INPUT
CONTROL ACTION
DISCR VS KEY SEL
DUAL TUNING SEL
94

Table 4-10 Loop Prompts

Range/Selections
Enter a value 0.1 to 100 or
OFF.
Enter a value 0.1 to 100 or
OFF.
OFF, discrete parameter, 0, 1
OFF, discrete parameter, 0, 1
Reverse (REV) or Direct (DIR)
Acting Control.
OFF, discrete parameter, 0, 1
OFF, discrete parameter, 0, 1
Video Recorder – User Manual
Definition
This function affects the process variable approach to set
point when the process variable value is less than the set
point value. The value entered is the percent of span
deviation from set point at which a recalculation of the
loop integral value will occur. Enter a starting value equal
to the proportional band value (1/gain value) x 100 if Gain
is used, or OFF at initial configuration. The value may be
altered Online for final loop tuning. This function is useful
for batch startup from a "cold" condition to control
excessive overshoot when set point is reached.
Affects the process variable approach to set point when
the process variable value is greater than the set point
value.
This parameter takes the place of the Auto/Man button
when the DISCR VS KEY SEL discrete is ON (1).
AUTO/MAN SELECT = ON(1) = Manual mode
AUTO/MAN SELECT = OFF (0) = Automatic mode
When DISCR VS KEY SEL is OFF(0), AUTO/MAN SEL
has no effect.
Change Action Input. Selects the opposite control action
from that selected for the control action (see CONTROL
ACTION). Control action is opposite when the discrete
value is ON or "1".
When Reverse Acting Control is selected, the loop output
will increase as the process variable becomes less than
set point, and will decrease as it becomes greater than
the set point. When Direct Acting Control is selected, the
output action is opposite.
Discrete vs. Keyboard select. When this discrete is ON
(1), the Auto/Man and Set point buttons are disabled; their
functioning is transferred to the AUTO/MAN SELECT and
SETPOINT SELECT discretes. See AUTO/MAN SELECT
and SETPOINT SELECT. Status changes made by
AUTO/MAN SELECT and SETPOINT SELECT will remain
when DISCR VS KEY SEL is OFF (0).
When ON(1), selects the second set of tuning constants
(#2). A bumpless transfer (integral term adjusted)
calculation will be made on transition.