Fault Types, Causes, And Corrective Measures - Siemens SIMATIC S7 Functional Safety Manual

6.2.2

Fault types, causes, and corrective measures

The "Fault types, causes, and corrective measures" table below lists the messages of the
S7-1200 fail-safe SMs. These messages are displayed in the TIA Portal under "Online &
diagnostics" > "Diagnostics" > "Diagnostic buffer". When you highlight an individual text line
in the diagnostic buffer, the Event ID for that text item is displayed, along with module
identity and location that generated the message. You may need to expand the window to
see all information.
Table 6- 6 Fault types, causes, and corrective measures
Event ID Diagnostic mes-
sage
0x0001 Short-circuit
0x0005 Overtemperature
0x004D PROFIsafe
communication
error (CRC)
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA
Fail-safe signal Description
module
SM 1226 F-DQ A channel problem
4 x 24 VDC has been detected
where either the P
terminal or M termi-
nal is at an unex-
pected potential.
All
Overtemperature
•
at microcomputer
Overtemperature
•
at I/O
All Transmission error in
data message frame:
Data inconsistent
(CRC (cyclic redun-
dancy check) error)
Fail-Safe signal module (SM) diagnostics
Possible causes Corrective measures
Short-circuit of the Eliminate the short-circuit.
output
Short-circuit be- Eliminate the short-circuit.
tween channels with
different signals
Output overload Eliminate the overload.
"Maximum readback Increase "Maximum read-
time switch on test" back time switch on test" if
value is configured permissible.
too small
Short-circuit of out- Eliminate the short-circuit.
put to M
Defective output Replace the fail-safe signal
driver module (SM).
Shutdown due to Check the ambient tem-
violation of high perature. Once the fault
temperature limit has been eliminated, the
value in the module power must be switched off
case and on.
Communication
•
interference be-
tween the fail-safe
•
CPU and the fail-
safe signal module
(SM) (for example,
due to electromag-
netic interference in
excess of limits or
sign-of-life monitor-
ing error)
6.2 Fault diagnostics
1
Check the communica-
tions connection.
Eliminate the interfer-
ence.
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