34
Configuring the PROFIBUS-DP network
Section 2-6
Example
For the PROFIBUS-DP Gateway Unit, the I/O modules for two E5ZN devices,
and two E5_N devices have been selected, see figure above. The E5ZN
devices have Compoway-F addresses 1 and 2, the E5_N devices have Com-
poway-F addresses 3 and 5. Address 4 is not used in this example.
Watchdog Settings
Apart from the I/O module selection, the Configuration tab also contains the
settings for two other parameters.
1.
Enable Watchdog Control
This parameter will enable/disable the monitoring of the Master-Slave
communication in the slave device. If enabled, the slave will stop I/O data
exchange with the Master, if the Master has not sent any request message
to the slave, within the configured Watchdog time. Furthermore, the slave
will
• switch its outputs to a known state.
• signal its change of state in a diagnostics message, the next time the
Master addresses the slave.
• request re-parameterization from the Master, before resuming I/O
data exchange.
If disabled, the slave will remain in data exchange, even if the Master is not
communicating, thus maintaining its outputs in the latest known state,
based on the last I/O data exchange message.
2.
Watchdog Interval
This value is the watchdog time-out related to the Master-Slave communi-
cation time out.
Note
Enabling the Watchdog Control is highly recommended for safe operation of
the network.
!Caution
In the current version of CX-Profibus, the watchdog value for each of the
slave devices is overruled by the value determined by the Master DTM.
Therefore, changing the value in the Generic Slave DTM has no effect.
2-6-3
Setting Parameters
The parameters are sent by the Master unit to the slave device prior to estab-
lishing I/O data exchange. The slave device will reject incorrect parameters
and not establish I/O data exchange, unless the parameters are changed.
In general there will be two types of parameters.
• Common Parameters
Most of the slave devices require at least the common parameters. These
parameters apply to the whole slave device.
• Module Parameters
Modular slaves often apply parameters related to a specific I/O module,
e.g. the physical slave device consist of a number of hardware modules,
each defining an amount of I/O data, requiring its I/O module selection
and requiring its own parameters.
Example
The Parameter tab of the PROFIBUS-DP Gateway Unit is shown in the figure
below. It lists the parameters for the selected temperature controller the
E5ZN-Extended 2 Channel 11WI/3WO. The parameter captions are listed in
the left column and the options can be set in the right column. In order to
change settings, double-click the required parameter row with the left mouse
button. Depending on the parameter type, either a drop-down list will become
available for selection or a value can be entered.
