PROFIBUS
CX8030 / CX8031
78
Version: 1.6
Diagnosis type
Description
Related to the station
Messages relating to the general readiness of a
device for operation such as over-temperature or
under-voltage
Related to the module
These messages indicate that diagnostic signals are
pending within a specific I/O sub range of the device
(e.g. an 8 bit output module)
Related to the channel
Here the cause of an error is related to a single input/
output bit (channel), such as a short circuit on output
2
The Beckhoff PROFIBUS slaves from the IPxxxx-B310, IL230x-B310 and IL230x-C310 series support the
PROFIBUS DP diagnostic functions. Assessment of the diagnostic data by means of the controller depends
on the support for the PROFIBUS master. Please refer to the device manuals for the master interfaces for
details of how to handle the diagnosis.
Sync and Freeze Mode
In addition to the user data traffic related to the device, which is automatically dealt with by DPM1, a DP
master has the option of sending control commands to one DP slave, to a group of them or to all of them at
the same time. These control commands are transmitted as multicasts. These control commands can be
used to specify the sync and freeze operating modes, in order to synchronize the DP slave. They permit
event-controlled synchronization of the DP slaves.
The DP slaves start
sync mode
when they receive a sync control command from the assigned DP master.
In this operating mode, the outputs of all the addressed DP slaves are frozen at their current values. In the
following user data transmissions, the DP slaves store the output data, but the output states themselves
nevertheless remain unchanged. Only when the next sync control command is received from the master the
stored output data is switched through to the outputs. Sync operation is ended with an unsync control
command.
A freeze control command similarly causes the addressed DP slaves to enter
freeze mode
. In this operating
mode the states of the inputs are frozen at their current value. The input data is only updated again when the
DP master has sent the next freeze control command to the devices concerned. Freeze operation is ended
with an unfreeze command.
System behavior
The system behavior is also standardized in PROFIBUS DP, so that devices can to a large extent be
interchanged. It is largely determined by the operating condition of the DPM1. This can either be controlled
locally, or over the bus by the project design device.
The following three principal conditions are distinguished:
Operation mode
Description
Stop
There is no data traffic between the DPM1 and the
DP slaves. The Bus Coupler only addresses the Bus
Terminals once after the power has been switched on
(none of the I/O LEDs are lit).
Clear
The DPM1 reads the input information from the DP
slaves, and maintains the outputs of the DP slaves in
a safe state (depending on the reaction to fieldbus
errors, the green I/O LED is lit and the outputs are
set).
Operate
The DPM1 is in a data transfer phase. In the course
of cyclic data traffic the inputs of the DP slaves are
read and the output information is transmitted to the
DP slaves (the green I/O LED is lit).
The DPM1 sends its local status at a configurable time interval using a multicast command cyclically to all
the DP slaves that have been assigned to it. The reaction that the system has to the occurrence of an error
during the DPM1's data transfer phase, such as the failure of a DP slave, is specified in the
Auto-Clear
