Honeywell VRX180 Manuale Utente

 

Table 7-9  Tune Loop Prompts (continued) 

RESET #1 

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 setpoint. Bumpless manual to automatic 
transfer is canceled when proportional only control is 
selected. 

RATE #1 

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.) 

PROP. BAND #2 

 

See GAIN #1 

RESET #2 

 

See RESET #1 

RATE #2 

 

See RATE #1 

MANUAL RESET 

-100 to +100 

This feature functions only when OFF is configured for the 
loop’s RESET parameter. Enter a value equal to the desired 
loop output when the process variable is at setpoint. This 
allows correction of output to account for load changes to 
bring the process variable up to setpoint. 

SUPPRESS 

OVERSHOOT 

YES, NO 

This parameter set to YES limits overshoot of the Setpoint 
(SP) by the Process Variable (PV) after a disturbance in the 
process such as a load or SP change. Through fuzzy logic, 
the working SP of the control loop is dynamically modified by 
the control algorithm to reduce or eliminate overshoot. 

PRETUNE 

 

Pretune calculates optimum values for a loop's Proportional 
Band/Gain, Reset and Rate by analyzing the reaction of the 
loop to a  "step change" in setpoint or output.  After these 
new tuning values have been calculated you have the option 
of applying (installing) or not applying them to a preselected 
tune set of the loop. You can pretune a loop while another 
loop is pretuning. 

SET TIMEBASE 

5 MIN, 15 MIN, 30 MIN,  
1 HR, 2 HR, 4 HR 

Enter the timebase for the time axis of the tuning trend 
display.