Siemens Simatic S7-400 - Manual (Page 579)

Diagnostic Data of the Signal Modules
B-5
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Bytes 4 to 8 of the SM 421; DI 16 24 VDC
Byte 4
7 6 0 5 4 3 2 1
Byte 5
7 0
Channel type B#16#70: digital input
Number of diagnostics bits that the module
outputs per channel: 8 bits long
Byte 6
7 0
Number of channels of the same
type in one module: 16 channels
Byte 7
7 6 0
Channel error, channel 0
Channel error, channel 1
Channel error, channel 6
Channel error, channel 7
5 4 3 2 1
...
0
Byte 8
7 6 0
Channel error, channel 14
Channel error, channel 15
5 4 3 2 1
...
Channel error, channel 8
Channel error, channel 9
Figure B-3 Bytes 4 to 8 of the Diagnostic Data of the SM 421; DI 16 x 24 VDC
Bytes 9 to 24 of the SM 421; DI 16 24 VDC
Data record 1 with bytes 9 to 24 contains the channel-specific diagnostic data. The
figure below shows the assignment of the diagnostic byte for a channel of the
module.
7 6 0
Sensor supply missing
5 4 3 2 1
0 0
Configuring/parameter assignment error
Wire break
0 0 0
Figure B-4 Diagnostic Byte for a Channel of the SM 421; DI 16 x 24 VDC