Honeywell VRX180 SP DEC Slew Limit, SP LOW Limit & SP, High Limit, SP1 Tracking SP2, None

			Programming Function Blocks and Features
		Table 4-10 Loop Prompts (continued)
	Prompt	Range/Selections	Definition
SP INC SLEW LIMIT &		Enter a number	Working set point slew limits for increasing and decreasing
SP DEC SLEW LIMIT			slew rates. (Variable slew limits are available by
			programming a constant's Destination with IS or DS. See
			Program Constants, Section 4.16.)
SP LOW LIMIT & SP		OFF or number	Limits will be imposed on the working set point value,
	HIGH LIMIT		regardless of source. A set point value above or below the
			limits will be entered into the loop at the limit value. OFF entry
			will assume process variable limits. (Variable limits are
			available by programming a constant's Destination with HS or
			LS. See Program Constants, Section 4.16.)
	SP1 TRACKING	SP2, NONE	A selection of Set point #2 will cause the Set point #1 value to
			be set to the Set point #2 value on a transfer from Set point
			#2 to Set point #1. Set point #1 adjustment may be made
			after the transfer.
	SUPPRESS	YES, NO	This parameter set to YES limits overshoot of the Set point
	OVERSHOOT		(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.

ATTENTION

Regardless of the setting of this SUPPRESS OVERSHOOT selection, overshoot is not suppressed when the process disturbance causes an initial deviation (PV-SP) value between -0.7 and +0.7 engineering units. Consequently, overshoot may not be suppressed in applications which require numerically small control loop PV ranges such as carbon potential where this range is typically 0.0 to 2.0 engineering units.

WILD VARIABLE	Enter an analog input (AIn OV) or calculated value (CVn OV)
	parameter that represents a second input signal applied to
	the ratio control loop whose value will be multiplied by the
	RATIO SETPOINT multiplier. The product of this multiplication
	may be specified as the ratio control loop’s working set point
	and can be biased by specifying a RATIO BIAS value. This
	input parameter is referred to as the “WILD VARIABLE” since
	the ratio loop has no control over its value whatsoever. In the
	fuel-air ratio control examples used in RATIO SETPOINT
	AND RATIO BIAS, fuel flow was for all intents and purposes
	the WILD VARIABLE.
	Note that the typical function block diagram one will use to
	represent a ratio control loop is illustrated in Figure 4-1.

Video Recorder – User Manual 99