Honeywell VRX180 user manual Function Generator Prompts

Programming Function Blocks and Features

Function Generator

This CV type can be used to characterize a valve (Figure 4-8) or an input signal (Figure 4-9). You enter a custom curve of up to 19 segments (20 X,Y coordinates). The input is compared with the X values and its corresponding Y value becomes the output CVn OV. Interpolation between coordinates is straight line. See Figure 4-7.

If the input value is outside the range of X values, the nearest X value is used, the output will be clamped to the corresponding Y value and the displayed output value will flash.

Y6
Y5
Y3, Y4
Y1, Y2
X1	X2	X3	X4	X5	X6

Figure 4-7 Function Generator Curve

Table 4-33 describes the Function Generator prompts. See Table 4-2 for additional prompts.

Table 4-33 Function Generator Prompts

Prompt	Range/Selections	Definition
RANGE LOW	OFF or number	Enter the output’s lower display limit. Output is not clamped
		or flashed when it exceeds this limit. Default value is Y1
		value.
RANGE HIGH	OFF or number	Enter the output’s lower display limit. Output is not clamped
		or flashed when it exceeds this limit. Default value is Y1
		value.
INPUT	OFF, analog parameter,	This value will be compared with the X values of the curve.
	number	The corresponding Y value will be the CV output.
X1, Y1, X2, Y2…X20,	OFF or number	Use these prompts to plot a curve using 2 to 20 X,Y
Y20		coordinates. X values must increase as Xn increases.
FEEDBACK	OFF, analog parameter,	For valve characterization, select AO# BC to propagate the
	number	back calculation (BC) value from a downstream Analog
		Output. Also, program the upstream loop’s feedback with
		this CV’s back calculation value (CV# BC). See Figure 4-8.
		Attention: If feedback is programmed to an analog
		parameter or a number, the X and Y values must define a
		curve that is not bell shaped or complex. That is, all Y values
		must be increasing or decreasing.

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