Honeywell VRX180 - Manual (Page 111)

Programming Function Blocks and Features
Video Recorder – User Manual 97
Table 4-10 Loop Prompts (continued)
Prompt Range/Selections Definition
RATE#1 &
RATE#2
0.02-10.00 minutes Modifies the loop output based on the rate of change of the
process variable. The output is modified by a value that
assumes the rate of change of the process variable will
continue for the time period specified. Enter a starting value
or OFF at the time of configuration. The value may be altered
Online for final loop tuning. For loops with dual tuning, Rate 1
is the rate for the first set of tuning parameters. Rate 2 is for
the second set. (Variable Rate1 is available by programming
a constant's Destination with RT. Program Constants, Section
4.16.)
RESET#1 &
RESET#2
0.005-99.99 repeats/minute Determines the period of time for a repeat of the proportional
gain output. Enter a starting value at initial configuration. The
value may be altered Online for final loop tuning. For loops
with dual tuning, Reset 1 is the time for the first set of tuning
parameters. Reset 2 is for the second set. (Variable Reset1
is available by programming a constant's Destination with RS.
See Program Constants, Section 4.16.)
A value of OFF may be entered to allow proportional-only
control. When turned off, the manual reset value determines
the loop output at set point. Bumpless manual to automatic
transfer is canceled when proportional only control is
selected.
RESET LIMIT OFF or 100 to 200%. This value restricts the calculated integral value of the loop
during Cold Start or on a manual-to-automatic transfer.
RATIO BIAS Enter a bias value to be used in calculating the working set
point of the ratio control loop. This is essentially a value that
will be added to the product that results when RATIO
SETPOINT is multiplied by the ratio loop’s wild variable input
value. For example, in the fuel-air ratio control scenario
introduced in the RATIO SETPOINT section, suppose fuel
flow is the wild variable that measured to be 60. With the
RATIO SETPOINT prompt set to 0.5, the result will be 30
when the RATIO SETPOINT is multiplied by the fuel flow. If
the RATIO BIAS prompt is then set to 10, the actual set point
that the ratio loop will use to control air flow will be 30 + 10 =
40.
To make a ratio control loop’s working set point equal to:
(RATIO SETPOINT x Wild Variable value) + RATIO BIAS
the loop’s working set point must be toggled to SP2 using the
“SP (Set Point select)” key while viewing the loop’s ON LINE
display. Refer to Figure 4-1.