Honeywell VRX180 Manuale Utente

 

Table 4-10   Loop Prompts (continued) 

IN DECIMAL 

POSITION 

Select decimal position 

Used for all input parameters of the loop. 

INTERACTIVE 

YES, NO 

Select interactive (YES) or noninteractive (NO) for the control 
algorithm operation.  Interactive causes the Gain, Rate, and 
Reset terms to interact to make up the proportional term of 
the algorithm (similar to analog controllers).  In noninteractive 
the proportional term is simply related to Gain. 

LATCHING 

YES, NO 

Select the desired action required after a failure to the 
failsafe status. 

When the loop’s PV or Set point #2 fails, the downstream 
function block activates its failsafe (See Table 9-3, Default 
condition column).  If latching = YES, when the failure is 
corrected the operator must take specific action to cancel 
these failsafe measures and return the loop to normal 
operation.  (See Table 9-3 for action needed.)  If latching = 
NO, when the failure is corrected the loop will automatically 
return to normal operation with no action needed by the 
operator. 

MANUAL OFF 

OFF, discrete parameter, 0, 
1 

When this discrete input goes ON (1) it causes the control 
output to go off. 

MANUAL RESET 

-100 to +100 

This feature functions only when OFF is entered for RESET. 
Enter a value equal to the desired loop output when the 
process variable is at set point. This allows correction of 
output to account for load changes to bring the process 
variable up to set point. 

OUTPUT LOW LIM & 

OUTPUT HIGH LIM 

OFF or number 

For cascade primary loop, set to PV LOW LIMIT and PV 
HIGH LIMIT of the cascade secondary loop, respectively. 

OUTPUT TRACKING 

0-100%, Analog parameter, 
OFF 

This will be the loop's output value when the FORCE 
REMOTE MAN input to the loop is high (1). See Force 
Remote Man. 

PROCESS 
VARIABLE 

OFF, analog parameter, 
number 

Process variable for the loop. 

PROP BAND#1 & 

PROP BAND#2 

 

See GAIN#1 OR GAIN#2 

PV LOW LIMIT &   

PV HIGH LIMIT 

OFF or number 

Enter the high and low limits for the process variable being 
controlled. Loop tuning parameters are based on the span 
selected by the high and low limit values. 

PV TRACKING 

PV, OFF 

A selection of Process Variable (PV) will cause Set point #1 
of the control loop to track the process variable when the 
loop is in Manual mode. A transfer to Automatic mode will 
maintain the tracked set point value as the working set point 
of the loop unless the loop was operating from Set point 2 
prior to the transfer to Manual.