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Festo — CPX-F8DE-P — 2022-10d
Safety
Term/abbreviation
Meaning
PROFIsafe
Safety-related bus profile for PROFIBUS and PROFINET IO that, in con-
junction with PROFIsafe-compliant devices (F-Host and F-Device), facili-
tates correct and reliable transmission of safety messages.
Mechanisms for safe transmission and error detection:
–
CRC signatures (data integrity test)
–
consecutive numbering of the safety messages,
–
address checking
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PROFIsafe address
–
time monitoring.
In the event of errors, the F-Device can automatically trigger predefined
safety measures. The consecutive numbering enables the recipient to
check that all messages are received in the right order.
For this purpose, the F-Host and the F-Device have their own state
machines, which are synchronised using a control and status byte.
Correct synchronisation is monitored by incorporation of counter values
in the calculation of the CRC signature.
PROFIsafe address
In order to identify the addressee of a message, every PROFIsafe-ena-
bled device or module has its own unique PROFIsafe address. The PRO-
FIsafe address is specified in the configuration program and set via the
DIL switch on the PROFIsafe-enabled device or module. Configuration
errors are automatically detected by comparing the target and actual
configuration.
PROFIsafe monitoring time Monitoring time for safety-related communication between F-Host and
F-Device.
Process image
The process image is part of the controller system memory. At the
start of the cyclical program, the signal states of the input modules
are transferred to the process image for the inputs. At the end of the
cyclical program, the process image for the outputs are transferred to
the output modules as the signal state.
Process error
The monitored sensor signals have taken an invalid combination.
Cross circuit
Accidental electrical connection between signals. Cross circuits falsify
the signal and cause loss of the safety function.
Cross-circuit monitoring
Function that detects possible cross-circuiting in the circuits connected
to the device and that sets a safe mode for the device and/or for the
input channel affected. This can be implemented by
è
cycle monitoring and/or discrepancy monitoring.