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Digitax ST User Guide

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9.8.1 PDO test mappings

For the purpose of the example this section will follow the steps required
to set up cyclic communications using one RxPDO and two TxPDOs.
These PDOs will consist of the mappings shown in Table 9-2:

Table 9-2 PDO test mappings

It is strongly recommended that the latest firmware be used where
possible to ensure that all features are supported.
Due to the large number of different masters that support CoE, details
cannot be provided for a specific master. Generic support is available
through your supplier or local Emerson Industrial Automation centre.
Before contacting your supplier or local Emerson Industrial Automation
centre for support please ensure you have read Chapter
14

Diagnostics

on page 183 of this manual and have checked that the

SDO/PDO configurations are correct.

9.8.2 EtherCAT XML file

Emerson Industrial Automation provides EtherCAT device description
files (in the form of .xml files). These files provide the master with
information about the EtherCAT interface and drive configuration to aid
with its configuration. These files can be obtained from your local
Emerson Industrial Automation Centre or supplier. They should be
placed in the directory specified by the master e.g. when using TwinCAT
this could be C:\TwinCAT\Io\EtherCAT.

The master may have to be re-started for the file to be loaded.

9.8.3 Configuring the EtherCAT interface for cyclic

communications

Unlike other Emerson Industrial Automation fieldbus communication
protocols, CoE does not require that any module parameters be
changed in order to achieve communications. The baud rate of the
network is fixed and the module is automatically allocated an address.

To check that the ethernet cable connected to the EtherCAT interface on
the drive is connected correctly, look at the LED on the front of the
EtherCAT interface relating to the connector being used, if this light is a
solid green color then a link is established with the master, if this light is
off then check the cabling and also check that the master has started
communications.

In the master, scan the network ensuring that the EtherCAT interface is
connected correctly to the master. If the network is configured correctly
the EtherCAT node(s) should be visible in the PLC master.

Decide on the input / output data you wish to send cyclically (objects
and/or parameters).

Cyclic data is implemented on CoE networks by using "Process Data
Objects" or PDOs. Separate data objects are used for receiving
(TxPDOs - from the slave to the master) and transmitting (RxPDOs -
from the master to the slave) data.

These PDOs contain the cyclic data (objects and/or parameters), the
RxPDOs available are 1, 2, 6 and 22, the TxPDOs available are 1, 2, 3,
6 and 22 (for more information on these PDOs including default
mappings please see section 9.16.2

Figure 9-3 EtherCAT interface PDO configuration

RxPDO1, TxPDO1 and TxPDO6 will need to be enabled in the master.
Once enabled you will need to add mappings to the PDOs.

The format used when mapping objects to PDOs is as follows:

•

Index: Object index number (0x0000)

•

Sub-index: Object sub-index number (0x00)

•

Size: Dependant on the size (in bytes) of the object to be mapped
(range: 1-4)

The format used when mapping drive parameters to PDOs is as follows:

•

Index: menu number

•

Sub-index: 0x00 + parameter number

•

Size: Dependant on the size (in bytes) of the object to be mapped
(range: 1-4)

For example Pr

20.21

would be index 0x2014, sub-index 0x15 and the

size would be 4 (the parameter is a 32-bit signed value).

The values are normally expressed in hexadecimal, so care must be
taken to enter the correct parameter number.

For this example the following objects will need to be set in order to
achieve the mappings of the parameters/objects in the PDOs.

Table 9-3 Cyclic data mapping configuration

The format used to define the value of a mapped object is as follows:
Bit 0 to 7: Length of the mapped object in bits (if a gap, bit length of the
gap).
Bit 8 to 15: Sub-index of the mapped object (if a gap, zero).
Bit 16 to 31: Index of the mapped object (if a gap, zero).

The maximum number of mappings in one PDO is five. There are no
restrictions on the data length of these 5 parameters (i.e. It is possible to
map five, 32-bit parameters in one PDO). It is also possible to use a
maximum of two RxPDOs and two TxPDOs.

RxPDO1

TxPDO1

TxPDO6

Mapping 1

0x6040 (

controlword

)

(16-bits)

0x6041 (

statusword

)

(16-bits)