Depassivation Block Fb 255 - Siemens SIMATIC S5 Manual

Blocks
6.1.7

Depassivation Block FB 255

Defective sensors and actuators are often the cause of passivation of I/O modules. If you can
rectify the faults in PLC RUN, FB 255 allows passivation to be revoked; the depassivated I/O
module is then referenced again by the PLC.
You may only call FB 255 in the cyclic part of the program (OB 1). FB 255 must not be called in time-
controlled or interrupt-driven program parts.
When assigning the FB 255 parameters, you must specify the following:
• a bit which initiates depassivation in the event of an edge change from 0 to 1
• a datum in KF format with the signal group for the I/O module to be depassivated
• a byte for FB 255 messages
Calling and assigning parameters
Parameter Meaning
SIGR Signal group
DEPA Depassivation bit
(positive edge)
PAFE Message byte
Note
Before depassivating the I/O module of a signal group with FB 255, you must branch to
a subroutine in your control program. You must evaluate all the variables required for
the process in this subroutine and if necessary update or initialize them
6-14
Assignment
D KF
I BI I0.0 to 127.7
F2.0 to 199.7
Q0.0 to 125.7
Q BI 00 = Depassivation successful
H
11 = Signal group has not been
H
configured or passivated
21 = Signal group can no longer
H
be passivated (error no
longer in error DB)
31 = Depassivation has not been
H
tested
41 = FB 255 parameters wrongly
H
assigned
51 = No signal group has been
H
passivated
DO = Depassivation being
H
executed now
2...28
Name
S5-115F Manual
STL
: SPA FB 254
: DEPASS
: SIGR
: DEPA
: PAFE
EWA 4NEB 811 6149-02