Yokogawa EJX930A - Manual (Page 80)

A1-3
IM 01C25T02-01E
A1.3 Line-segment Factor Determination Section
When the mode is AUTO and no bit in BLOCK_ERR is set, the "gradient" and "intercept" of a line passing
through two points that are considered line-segment approximation values are determined.
A1.3.1 Conditions for Configuring Valid Coefficients (CURVE_X, CURVE_Y)
No write error is generated with respect to the settings in CURVE_X and CURVE_Y. However, a configuration
error occurs in the following cases:
1. "+INFINITY" has been configured for X1 or Y1.
2. "–INFINITY" has been configured for each X or Y.
3. The values of CURVE_X are not increasing in a monotone manner (X1 < X2 < ... < X20 < X21).
(If SWAP_2 is off, it is acceptable if the values of CURVE_Y do not increase or decrease in a monotone
manner.)
4. The values of CURVE_Y are not increasing or decreasing in a monotone manner when SWAP_2 is on.
If a configuration error occurs, the Block Configuration Error bit in BLOCK_ERR is set, causing the mode to
change to O/S.
Example of the case where SWAP_2 is off:
Y
Output
Y6
(High limit)
Y1
(Low limit)
X1 X2 X3 X4 X5 X6 X7 =INFINITY X
Input
FA0103.ai
Figure A1.3 Example of Curve (SWAP_2 = off)
The range of CURVE_X: X1 to X6 (X7 and above are invalid because "+INFINITY" has been configured for
X7* 1 .)
The X1 to X6 values always increase in a monotone manner (X1 < X2 < X3 < X4 < X5 < X6).
If an input value is smaller than X1, it is set to Y1.
If an input value is larger than X6, it is set to Y6.
The range of CURVE_Y: Y1 to Y6
It is acceptable if the Y1 to Y6 values do not increase in a monotone manner.
However, if the setting of SWAP_2 is changed from off to on, the values of CURVE_Y must increase or
decrease in a monotone manner. Thus, if a value of CURVE_Y does not increase or decrease in a monotone
manner in this setting, the mode changes to O/S, causing the Block Configuration Error bit in BLOCK_ERR to
be set.
*1: For any points of the curve that are not used, configure "+INFINITY" for all of them.