Festo CPX-FVDA-P2 Original Instructions Manual page 18

General safety instructions
Term/abbreviation
PROFIsafe
PROFIsafe address
PROFIsafe monitoring
time
Process image
P-switch (high-side
switch)
18
Meaning
Safety-related bus profile for PROFIBUS and PROFINET that, in conjunction
with PROFIsafe-compliant devices (F-Host and F-Device) facilitates 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 (
– Time monitoring
In the event of errors, the F-Device can automatically trigger predefined
safety measures. Due to the consecutive numbering, the recipient can
check whether they have received all the messages in the right order.
For this purpose, the F-Host and the F-Device are equipped with their own
state machines, which are synchronised using a control and status byte.
Correct synchronisation is monitored by including counter values in the
CRC signature calculation.
In order to identify the addressee of a message, each PROFIsafe-enabled
device or module has its own unique PROFIsafe address. The PROFIsafe
address is specified in the configuration program and set via the DIL switch
on the PROFIsafe-enabled device or module. Configuration errors are auto-
matically detected by comparing the target and actual configuration.
Monitoring time for safety-related communication between F-Host and F-
Device
The process image is part of a controller's 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.
Switch in the 24 V current path of an output channel.
Each output channel has a 24 V and a 0 V current path between which the
load is switched. With the CPX-FVDA-P2, these current paths are switched
together and at the same time, although independently of each other.
The P-switch switches the 24 V current path and the M-switch switches the
0 V current path of the output channel. Both switches (P-switch and M-
switch) must be closed in order for voltage to be applied to the load.
For the CPX-FVDA-P2, the P-switch and M-switch of an output channel are
controlled by different micro controllers for safety reasons.
PROFIsafe address)
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Festo — CPX-FVDA-P2 — 2018-10b