Error management
Original instructions
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Principle
This section describes the error recording and notification routines of
function blocks in the Conditioning, Controller, Output Processing and setpoint processing families.
Most function blocks in these families are provided with a STATUS output word.
Each bit of the STATUS parameter can be used for notifying an error, an alarm or some information. The meaning of the first 8 bits of the STATUS word is the same for all function blocks. The meaning of the subsequent bits (bits 8 to 15) is different for each function block.
Status word
The following table shows the meaning of the bits common to all the function blocks in the first byte of the STATUS word. Further information can be found in the description of each function block.
Bit
Meaning
Type
Bit 0 = 1
Error in a calculation with floating point values (e.g. calculation of the square root of a negative number)
Error
Bit 1 = 1
An unauthorized value being recorded on a floating point input can be caused by the following:
  • the value is not a floating point value
  • the value is infinite (e.g. the result of a calculation previously enabled to the function block)
Error
Bit 2 = 1
Division by zero with calculation in floating point values
Error
Bit 3 = 1
Capacity overflow during floating point value calculation
Error
Bit 4 = 1
An input parameter is outside the zone. The value internally used by the function block is capped.
Warning or information
(Note 1)
Bit 5 = 1 (Note 2)
The main output of the function block has reached the lower threshold
Information
Bit 6 = 1 (Note 2)
The main output of the function block has reached the upper threshold
Information
Bit 7 = 1
The lower and upper threshold of the input parameter zone are identical
Error
Note 1 (input parameter)
NOTE: If the value originates from a parameter zone with derived data types (typically the PARA parameter), a warning message is given because of the capping and bit 4 is set to 1. If the value originates from a simple type of inputs, no warning message is given, but bit 4 of the STATUS word is set to 1.
Note 2 (thresholds)
NOTE: If the upper and lower threshold parameters of an output have been invented (e.g. out_min ≥ out_max), the function block switches the output to the lowest value (i.e. auf out_max).