Festo EMCA-EC-67 CO Series, Description

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3 EtherCAT with FHPP
Festo – EMCA-EC-C-HP-EN – 2017-11e – English 53
3.7 Process data communication
With Process data communication, process data (e.g. setpoint and actual values) are exchanged cyclic­
ally between the EMCA and the network participants (e.g. controller). With each process data frame
that is run through, the process data are read and written to. In the EMCA, the controller for process
data communication is assigned permanently to Sync Managers 2 and 3. Transmission of mapped pro­
cess data objects PDO (Process data objects) takes place via sync channels 2 and 3.
From status “Safe Operational”, EMCA process data communication is enabled. From this status on­
wards, the EMCA transmits current actual values to the controller. When status “Operational” is
reached, incoming process data objects PDO are processed and executed by the EMCA. Synchroniza­
tion of the EMCA can be controlled by Distributed Clocks DC
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Controllers
RxPDO
(transmitted data, e.g. setpoint value)
TxPDO
(received data, e.g. actual value)
EMCA
Process data output
Process data input
RxPDO Mapping
Object 1600
h
… 1603
h
TxPDO Mapping
Object 1A00
h
… 1A03
h
Fig. 3.7 Access procedure via process data objects PDO
3.7.1 PDO Mapping
With PDO mapping, application-specific data sets for data interchange can be created.
Objects for PDO mapping
The following objects are available for mapping the PDO process data objects:
Index Name Page
1600
h
1
st
receive PDO mapping RxPDO1 54
1601
h
2
nd
receive PDO mapping RxPDO2 55
1602
h
3
rd
receive PDO mapping RxPDO3 56
1603
h
4
th
receive PDO mapping RxPDO4 57
1A00
h
1
st
transmit PDO mapping TxPDO1 58
1A01
h
2
nd
transmit PDO mapping TxPDO2 59
1A01
h
3
rd
transmit PDO mapping TxPDO3 60
1A01
h
4
th
transmit PDO mapping TxPDO4 61
Tab. 3.26 Objects for PDO mapping