MOVIDRIVE
®
PROFIBUS DFP11A
19
The PROFIBUS-DP
Interface
3
3.2
Ident Number
Each DP master and DP slave must have an individual identification number assigned to them by
the PROFIBUS User Group so that the units connected to the bus can be uniquely identified. When
the PROFIBUS-DP master is started, it compares the Ident Numbers of the connected DP slaves
with those specified by the user. User data transfer is activated once the DP master has ascertained
that the connected station addresses and unit types (Ident Numbers) agree with those specified.
This process provides a high degree of security against configuration errors.
01072AEN
Fig. 16: Ident Number of the MOVIDRIVE
®
family
The Ident Number is defined as an unsigned 16-bit number (Unsigned16). The PROFIBUS User
Group has specified the Ident Number 5100hex (24576dec) for the MOVIDRIVE
®
range of drive
inverters (Fig. 16).
3.3
Watchdog Timer
Each DP slave must have a watchdog timer so it can detect a failure of the DP master or the com-
munications link. If no data are transferred between the DP master and DP slave within the speci-
fied timeout period, the slave must automatically switch its outputs to a safe state.
The MOVIDRIVE
®
drive inverter maps the timeout period which is defined when the DP master is
configured to parameter P791 Fieldbus Timeout (Fig. 25). This parameter consequently reflects the
currently configured timeout period. If the watchdog timer is not active, the parameter will have a
value of 650.00 seconds.
01228AEN
Fig. 17: A fieldbus timeout period of 200 ms configured in the DP master
When the timeout period expires, the drive inverter invokes the fault response specified beforehand
in parameter P831 Timeout Response. This means the response of the drive inverter when the bus
goes down can be adapted to that of the drive application. For example, conveyor belts can con-
tinue to run at the most recent valid setpoint speed or brought to a stop very quickly.
Expiry of the timeout period is indicated on the option pcb by the red BUS FAULT LED. At the same
time, the drive inverter also indicates an error in the 7-segment display, which is displayed as Error
Fieldbus Timeout in the MX_SHELL user interface on your PC (Fig. 17). Depending on the specified
fault response, the drive inverter may have to be reset to restore its normal status.
E
Q
MOVIDRIVE
Ident number: 6000
or 24576
®
hex
dec