Siemens SIMATIC S7-400 Reference Manual page 399

You enable a parameter by setting a logical "1" at the corresponding bit.
Table A-4
Byte 4
Byte 5
Substitute value
Byte 6
Substitute value
Only for 6ES7 421-7BH0x-0AB0
1
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
Data record 1 for parameters of digital input modules
Byte Bit
7
6
5
4
3
2
1
0
7
6
1
5
4
3
2
1
0
7
6
1
5
4
3
2
1
0
A.2 Parameters of digital input modules
On falling edge at channel 15
On falling edge at channel 14
On falling edge at channel 13
On falling edge at channel 12
On falling edge at channel 11
On falling edge at channel 10
On falling edge at channel 9
On falling edge at channel 8
Enable substitute value 1 on channel 7
Enable substitute value 1 on channel 6
Enable substitute value 1 on channel 5
Enable substitute value 1 on channel 4
Enable substitute value 1 on channel 3
Enable substitute value 1 on channel 2
Enable substitute value 1 on channel 1
Enable substitute value 1 on channel 0
Enable substitute value 1 on channel 15
Enable substitute value 1 on channel 14
Enable substitute value 1 on channel 13
Enable substitute value 1 on channel 12
Enable substitute value 1 on channel 11
Enable substitute value 1 on channel 10
Enable substitute value 1 on channel 9
Enable substitute value 1 on channel 8
Parameter sets of signal modules
Meaning
399