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Video Recorder – User Manual 239
Table 7-11 Pretune STOPPED Prompts (continued)
Prompt Range/Selections Definition
OUTPUT SIZE -100 to +100 Appears if loop is in Manual. Enter the largest change in
output (+ or -), in engineering units, that the process will
tolerate. The pretune will initiate and analyze this output
change.
SP STEP SIZE -100 to +100 Appears if loop is in Auto. Enter the largest change in
setpoint (+ or -), in engineering units, that the process will
tolerate. The pretune will initiate and analyze this setpoint
change.
START
Select to start the pretune function. See Before Starting
Pretune below.
Before Starting Pretune
Before starting Pretune, configure/adjust the loop as follows:
Auto/Manual: Either mode is acceptable. Changing the loop mode after starting pretune will abort the
pretune, causing an error message to appear.
Process Variable: Adjust setpoint or output to bring the process variable to normal operation range.
Adjusting or switching setpoints or output after starting pretune will abort the pretune, causing an error
message to appear.
Gain/Proportional Band, Reset: Use known good settings. Or, set Gain = 1.0 (PB = 100), Reset = 1.0
and place loop in Manual mode.
Rate: Optional. If OFF, pretune will not calculate a Rate.
Suppress Overshoot: Set to OFF. Pretune may detect changes to the working setpoint and abort. Turn
this setting back on after pretune is complete.
After Starting Pretune
After starting the pretune, do not change/adjust the loop mode, loop output, loop setpoint, or operating
mode. If you do, the pretune will abort. See Pretune Abort Messages later in this section.
Pretune IDENTIFYING & CALCULATING menus
During IDENTIFYING and CALCULATING status, a TUNE indicator appears on all primary displays (not
on menus) for the loop being pretuned.
Table 7-12 Pretune IDENTIFYING & CALCULATING Prompts
Prompt Definition
STATUS Status Identifying or Calculating. This is a read-only prompt.
PV Current process variable value of the loop being tuned. This
is a read-only prompt.
OUTPUT Current output value of the loop being tuned. This is a read-
only prompt.