F(x) discontinuity (step) [CHECK 031]

F(x) discontinuity (step) in Module 1,01,02 Block 1001 at S2 X value of 1.000

This message means that there is a step discontinuity in an F(x) function. This can lead to unexpected results if it is not intentional.

The function generator can legitimately give discontinuous results. Sometimes, as in the case of "dead bands" this is intentional. When the input is in a particular range, the output is set to an arbitrary value (often 0.0) because the sensor simply is not workable at that range.

In physical processes, discontinuities are rare. In most F(x) blocks with discontinuities, there is actually an error, often a result of typographical mistakes.

Example:

F(x) discontinuity (step) in Module 1,16,06 Block 4216 at S8 X value of 460.000.
( S2, S3)        439.0          0.0
( S4, S5)        440.0        150.0
( S6, S7)        460.0        150.0
( S8, S9)        460.0        143.0
(S10,S11)        480.0        143.0
(S12,S13)        480.0        143.0

The F(x) graph looks like this:

Fc001 discontinuity.png

This message shows a potential error in the system configuration, although most such errors prove to be harmless. It should be reviewed and hidden, unless it shows an issue that should be addressed.

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