Siemens SIRIUS 3RK3 Equipment Manual page 301

Note
Substitute values on failure of a slave
Depending on the AS‑i master used, on failure of the AS-i bus or CTT2 slave different substitute
values are generated by the master and transferred to the controller (0x7FFF or 0x0000). This
must be considered in the programming of the controller because otherwise messages will be
interpreted that are not present. The same applies to the freely interconnectable protocol data
(SLOT3_ASI#xx-Sy.z).
If the corresponding master is used, the input data are checked word by word for the value
0x7FFF. If the value 0x7FFF is received, the value 0x0000 must be used in the program.
The corresponding substitute value response can be taken from the documentation of the
master.
The data in the MSS are not affected by this. The substitute value 0x00 is always generated in this
case.
Control data:
Through a simulated AS-i slave with a CTT2 channel, an AS-i master or a controller connected to
it can write data to the safety relay. The following data can be written to the safety relay through
the cyclic CTT2 data transmission channel:
Byte Process data block "control data device"
Description
0 Reset
0
0 1 ... 1 7 Reserved=0
2 ... 7 SLOT3_ASI#xx-Q2.0
0 7
SLOT3_ASI#xx-Q7.7
xx: AS-i address
SIRIUS 3RK3 Modular Safety System
Equipment Manual, 07/2020, NEB926253002000/RS-AC/006
Description
[->]: On pos. edge 0 -> 1, the command is
executed once.
[0,1]:constant value: does not cause
command processing
[0]: fix
‑
7.6 Diagnosis using AS-Interface (CTT2 protocol)
Note
Device commands
Master call (CTT2 protocol) from AS-i
master to simulated non-safety-related
AS-i slave (CTT2) of the MSS 3RK3
Diagnostics / service
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