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Leuze electronic GmbH + Co. KG
MA 238
i
14
Service interface
The service interface can be accessed once the MA 238
i
housing cover has been removed and features
a 9-pin Sub-D connector (male). A crossed RS 232 connection cable is required to make the RxD, TxD
and GND connections.
Figure 4.3: Connecting the service interface to a PC/terminal
4.5
Fieldbus systems
Various product variants of the MA 2xx
i
series are available for connecting to different fieldbus systems
such as PROFIBUS DP, PROFINET-IO, DeviceNet and Ethernet or EtherCAT.
4.5.1 EtherCAT
General information on EtherCAT
EtherCAT is an Ethernet-based fieldbus initiated by the Beckhoff corporation. The EtherCAT Technology
Group (ETG) is the official standardization partner of the IEC working groups.
EtherCAT has been an IEC standard since 2005.
• IEC 61158: Protocols and services
• IEC 61784-2: Communication profiles for the specific device classes
All EtherCAT-specific communication mechanisms are described in detail in the standards mentioned
above. This technical description will describe parts of the IEC standard if this assists general under
-
standing.
EtherCAT topology
EtherCAT permits a multitude of topologies such as line, tree, ring, star and combinations of these. The
bus or line structure known from the fieldbuses is thus also available for EtherCAT.
Telegrams are sent on a wire pair in the "processing direction" from the master to the slave. The EtherCAT
device processes the frames only in this direction and passes them on to the subsequent device until the
telegram has passed through all devices. The last device sends the telegram back to the master on the
second wire pair in the cable in the "forward direction". Here, the EtherCAT always forms a logical ring
structure regardless of the topology installed.
From an Ethernet point of view, an EtherCAT bus segment is nothing more than a single, large Ethernet
participant which sends and receives Ethernet telegrams. Within the "participant", however, there is a
multitude of EtherCAT slaves rather than one single Ethernet controller with a downstream micro-
processor.
ATTENTION!
For the service PC to function, the RS 232 parameters must be the same as those of the MA.
The Leuze standard setting of the interface is 9600bd, 8N1 and STX, data, CR, LF.
5 GND
3 TxD
2 RxD
GND 5
TxD 3
RxD 2
1
1
PC/terminal
COM interface
MA 238
i
Service interface