Diagnostics Of Sm 338; Pos-Input - Siemens SIMATIC Manual

7.4.6

Diagnostics of SM 338; POS-INPUT

Introduction
The SM 338 provides diagnostics messages, i.e. it always provides all diagnostics messages
without user intervention.
Reactions to a diagnostic message in
Actions initiated by diagnostic messages:
● The diagnostic message is entered in the diagnosis of the module and forwarded to the
CPU.
● The SF LED on the module is lit.
● If you have set "Enable Diagnostic Interrupt" in
interrupt and calls OB 82.
Reading diagnostic messages
You can read detailed diagnostic messages using SFCs in the user program (refer to section
Diagnostics data of SM 338; POS-INPUT (Page 596)).
You can view the cause of the error in the module diagnostics data in
STEP 7
Diagnostic message using the SF LED
The SM 338 indicates errors at its SF LED (group error LED.) The
SF LED lights up when the SM 338 generates a diagnostic message. It goes dark after all
error states are cleared.
The SF LED also lights up to indicate external errors (short-circuit at the encoder supply),
regardless of the CPU operating state (at POWER ON.)
The SF LED lights up temporarily at startup, during the self test of SM 338.
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
7.4 Position decoder module SM 338; POS-INPUT; (6ES7338-4BC01-0AB0)
STEP 7
Online Help.)
Other signal modules
STEP 7 , the system triggers a diagnostic
STEP 7
(refer to the
509