Siemens SIRIUS 3RK3 - Failure of an AS-I Slave; Failure of the AS-I Bus

6.5.8.2 Failure of an AS-i slave
The AS‑i master cyclically scans all AS‑i addresses to ascertain whether new slaves have been
added. These scans are detected and evaluated by the AS-i monitor functionality. In this way, the
MSS 3RK3 can determine what slaves are on the bus and can independently detect the absence
of an AS‑i slave on the bus or the absence of the monitored AS‑i subnet.
Substitute value on missing slave/erroneous code sequence
If the MSS 3RK3 detects that a con󹪝gured AS‑i slave is missing, or that a safety-related AS‑i slave
is transmitting an erroneous code sequence, the logic processing at the relevant terminals
continues with the substitute value "0" for the terminals a󹪜ected.
It is possible to ascertain which slaves are missing or defective by reading out the actual status
of the AS-i slaves by online diagnostics in Safety ES.
Note
If the missing or defective AS‑i slave is a device that is not contained in the con󹪝guration of the
MSS 3RK3, there is no response.
Recovery of an AS-i slave
When the removed safety-related AS‑i slave (identical code sequence) is reinserted or when a
non-safety-related slave is plugged in with the corresponding slave pro󹪝le, work is resumed with
the received process value.
For the monitoring elements (e.g., EMERGENCY STOP), a startup test is required on recovery of
the safety-related slaves if any have been parameterized in the function element.
6.5.8.3 Failure of the AS-i bus
Entering safety mode even without the AS-i bus
When the system enters safety or test mode, if it is detected that the AS-i bus is not running or
is missing completely, the system enters safety mode nevertheless. This can take up to 30 s. In
this case, the process values of all con󹪝gured AS-i slaves are assigned the substitute value "0."
Operation
6.5 Connecting to the AS-i master via AS-Interface
SIRIUS 3RK3 Modular Safety System
Equipment Manual, 07/2020, NEB926253002000/RS-AC/006 233