Festo IFB05-03 Manual page 115

5. Diagnosis and error treatment
Program STL:
STEP
IF
THEN CFM 54
WITH
WITH
STEP
IF
AND
=
THEN JMP TO
OTHERWISE
Basic program
CALL FN54 (44, 23)
44
IF @Q0 AND $10 THEN...:I
Fig. 5/16: Example of program with Festo field bus
Festo P.BE−VIFB5−03−EN en 0503e
Example
Interrogation and evaluation of the diagnostic byte of a field
bus slave.
Field bus address
Processor system address:
Interrogation:
Solution
(1)
"Read status byte terminal 23
NOP
"Function module – call in CZE 4
C44 "CFM 44 in CFA
C23 "Address of field bus slave
(2)
"Bit no. 4 set in status byte?
(FU32 "CFM return parameter
$10) "Condition: Bit no. 4 = 1
K$10
V_error (3) "Jump to subprogram "Error"
NOP
:I Read status byte terminal 23 via CFM
Condition: Bit no. 4 = 1
23
4
With faults of V
inputs
(Bit no. 4) is to be branched
in the program.
With bit−by−bit masking
of the return parameter,
the contents will be
evaluated
(HEX10 = 0001.0000).
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