Siemens SIMATIC S7 - System Diagnosis Bytes

4-10
SM 338 Equipment Manual
(4) J31069-D401-U1-A0-7618
4.3.1 System Diagnosis Bytes
Note
The contents of the system diagnosis bytes are standardized, and fixed desig-
nations are used. The standa rdized term “channel” corresponds to a sensor
for the SM 338.
The system diagnosis bytes occupy the first 4 byte s of the diagnosis area.
They contain errors occurring at the module level. Their contents are de-
scribed in detail below.
7 0
0
Byte 0
Module malfunction
(Any error was detected.)
Internal error
(e.g., EPROM checksum wrong)
External error (e.g., cable break detected)
Channel error detected
Fault in the 24 V external voltage supply
Module parameters not assigned
Wrong parameters on the module
Module parameters not assigned
Valid parameters have not been transferred since booting took place. The bit
is reset after the correct parameters have been transferred.
Wrong parameters on the module
When accepting parameters, the SM 338 checks their plausibility within cer-
tain limits. A detected error is indicated here and cancelled after valid pa-
rameters have been received.
Module class
Channel information present
7 0
000
Byte 1
0011
Channel information present
The error which occurred on a channel (i.e., sensor) is described in more de-
tail in bytes 4 to 11.
Module errors
Module class,
channel informa-
tion
D
a
t
a
Communic
a
tion with the PLC