AXL E PB DI8 DO8 M12 6M
8430_en_03 17
PHOENIX CONTACT GmbH & Co. KG • 32823 Blomberg • Germany
phoenixcontact.com
14 Sync/freeze mode
The device supports sync and freeze mode.
The functions must be activated by the PROFIBUS master
in the parameter data.
Input and output data is written or read at defined times with
the sync and freeze commands.
If the device receives a sync command from the PROFIBUS
master at any given time, the current OUT process data is
transferred and frozen until the next sync command.
Similarly, the states of the inputs are transferred on the re-
spective freeze command and are frozen until the next
freeze command.
15 Diagnostic alarms
PROFIBUS enables the PROFIBUS device to store diag-
nostic information together with the error location and error
type.
In the default upon delivery the alarms are enabled, how-
ever, they can be disabled with parameters on startup.
An incoming alarm informs the PROFIBUS device that diag-
nostic information has been entered.
When the diagnostic information has been removed, an out-
going alarm is sent to the device.
If at least one piece of diagnostic information is stored, the
SF LED is on. If no diagnostic information is present, the SF
LED is off.
The following PROFIBUS diagnostic messages are indi-
cated by the PROFIBUS device:
– Overtemperature of the device
–Surge voltage of U
S
– Overload of U
S
–Surge voltage of U
A
– Undervoltage of U
A
– Short circuit of U
A
– Short circuit of an output
–Output overload
16 Monitoring
A process data watchdog is integrated into the device to
avoid uncontrolled setting/resetting of outputs in the event of
an error.
If device outputs are set, the controlling process must be
able to access the device.
In the event of an error, e.g., bus cable interrupted or func-
tion error in the controlling process, the device can respond
appropriately via the process data watchdog.
When activating the process data watchdog, it is started by
the first write process and the next write process is expected
within the timeout period. During error-free operation, the
write process is performed during the timeout period and the
watchdog is restarted (triggered).
If there is no triggering during the timeout period, an error oc-
curred. Two responses follow:
– All outputs are set to the configured substitute value.
– The BF LED indicates the corresponding state.
17 Substitute value behavior
If PROFIBUS communication fails or if no valid process data
is received from the PROFIBUS master, all device outputs
are set to the parameterized substitute values.
Reading calls do not trigger the process data
watchdog.
