Automatic control function programming manual ladder language

General Purpose Functions
6.17 Search for the Value of a Word rchw
Syntax
rchw(&source, w, step, n)
&source: Search start address.
w: Value of the word to be searched for.
step: Value of the search step in bytes.
n: Maximum number of search steps.
Search, with a step, for the first occurrence of word w starting from address &source.
The step can be positive or negative.
Positive step: The search is made by increasing addresses.
Negative step: The search is made by decreasing addresses.
Return code
Value found
Positive number equal to the number of steps made to the first occurrence.
Positive step: Return code = (occurrence address - &source)/step
Negative step: Return code = (&source - occurrence address)/(-step)
Value not found
-1: Value not found
Programming error causing a CPU fault
Access to a prohibited address:
- &source parameter error,
- &source+step*n outside authorised area.
6.18 Search for the Value of a Long Word rchl
Syntax
rchl(&source, l, step, n)
&source: Search start address.
l: Value of the long word to be searched for.
step: Value of the search step in bytes.
n: Maximum number of search steps.
Search, with a step, for the first occurrence of long word l starting from address &source.
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