Honeywell VRX180 user manual Before Starting Pretune, After Starting Pretune, Pretune below

		Online Operation Using Menus
	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.

Video Recorder – User Manual 239