Acyclical communication
77/98
SmartWire-DT Gateway | EU5C-SWD-ETHERCAT
DOC140901UM01EN | Revision 1 | English | 2015-03 | Released | Public
© Hilscher 2015
Note:
If no answer from the SWD slave has yet arrived at the gateway,
the
State
element (state of the response) has the value
1
(= „in progress“)
and the
Data
element (payload data) is omitted.
10.2.3
Example of a read request
10.2.3.1
Activating read request
In case the EtherCAT
®
master wants to read the error counter (SWD Index
127) of the 5
th
SmartWire-DT slave (slave address 5), and the expected
response should be no longer than 120 Bytes, the
SDO Download
Request
sent to the gateway looks as follows (gateway has Node ID
3
in
this example):
Syntax
Header
Data
Address
Object
index
Sub
index
Size
Slave
Address
SWD
Index
Request
Type
Length Job
ID
Reserved
Bytes
0x03 0x2200
0x01 0xA
0x05 0x7F
0x01 0x78
0x01 0x00
,
0x00
,
0x00
,
0x00
,
0x00
Table 22: Example SDO Download Request for a read request
10.2.3.2
Querying the state of the read request
Querying the state of the read request
The
SDO
Upload Request
sent by the EtherCAT
®
master to the gateway
looks as follows:
Syntax
Address
Object index
Sub index
0x03 0x2200
0x02
Table 23: Example SDO Upload Request for a read request
Answer of the gateway in case of an unfinished read request
If the gateway has not yet received the answer from the SWD slave, the
SDO Upload Confirmation
sent by the gateway to the EtherCAT
®
master
looks as follows:
Syntax
Header
Data
Address Object
index
Sub
index
Size
Slave
Address
SWD
Index
Request
Type
Length Job
ID State
Error Code
0x03 0x2200
0x02 0xA
0x05 0x7F
0x01 0x00
0x01 0x01
0x00000000
Table 24: Example SDO Upload Confirmation for an unfinished read request