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Appendix | EtherCAT Documentation
capaNCDT 6500
A 5.1.5 EtherCAT State Machine
The EtherCAT® state machine is implemented in each EtherCAT®. Directly after switch-
ing on the capaNCDT 6500, the state machine is in the “Initialization“ state. In this state,
the master has access to the DLL information register of the slave hardware. The mail-
box is not yet initialized, i.e. communication with the application (sensor software) is
not yet possible. During the transition to the pre-operational state, the Sync Manager
channels are configured for the mailbox communication. In the „Pre-Operational“ state,
communication via the mailbox is possible, and it can access the object directory and
its objects. In this state, no process data communication occurs. During the transition to
the „Safe-Operational“ state, the process-data mapping, the Sync Manager channel of
the process inputs and the corresponding FMMU are configured by the master. Mailbox
communication continues to be possible in the „Safe-Operational“ state. The process
data communication runs for the inputs. The outputs are in the „safe“ state. In the „Oper-
ational“ state, process data communication runs for the inputs as well as the outputs.
Initialization
Pre-Operational
Operational
Safe-Operational
Fig. 48 EtherCAT State Machine
A 5.1.6 CANopen over EtherCAT
The application level communication protocol in EtherCAT is based on the communica-
tion profile CANopen DS 301 and is designated either as “CANopen over EtherCAT” or
CoE. The protocol specifies the object directory in the sensor, as well as the communi-
cation objects for the exchange of process data and acyclic messages. The sensor uses
the following message types:
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Process Data Object (PDO). The PDO is used for the cyclic I/O communication, there-
fore for process data.
-
Service Data Object (SDO). The SDO is used for acyclic data transmission.
The object directory is described in the chapter CoE Object Directory.
A 5.1.7 Process Data PDO Mapping
Process Data Objects (PDOs) are used for the exchange of time-critical process data be-
tween master and slaves. Tx PDOs are used for the transmission of data from the slaves
to the master (inputs), Rx PDOs are used to transmit data from the master to the slaves
(outputs); not used in the capaNCDT 6500. The PDO mapping defines which application
objects (measurement data) are transmitted into a PDO. The capaNCDT 6500 has a Tx
PDO for the measuring data. The following measurements are available as process data:
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Counter
Measurement counter (32 Bit)
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Channel 1
Displacement Channel 1
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Channel 2
Displacement Channel 2
-
Channel 3
Displacement Channel 3
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Channel 4
Displacement Channel 4
-
Channel 5
Displacement Channel 5
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Channel 6
Displacement Channel 6
-
Channel 7
Displacement Channel 7
-
Channel 8
Displacement Channel 8
Summary of Contents for capaNCDT 6500
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