Festo EMCA-EC-67 CO Series, Описание

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3 EtherCAT with FHPP
Festo – EMCA-EC-C-HP-EN – 2017-11e – English 63
3.8.2 SDO Read command (SDO upload)
Using the SDO read command, the controller can access parameter data (Value) of the CoE object dir­
ectory CoE OD in the EMCA acyclically and can read them. Every request is confirmed by the EMCA with
a answer.
Controllers EMCA
SDO upload/Upload SDO ... request
(SDO read command)
Request
Answer
SDO upload/Upload SDO ... response
CoE OD
Object
Value
Fig. 3.8 Access procedure: Reading out parameter data
The SDOservice supports the following SDO read commands:
SDO Service Description
SDO upload expedited request Read para­
meter data
(upload)
1 … 4 bytes of us­
age data (expedi­
ted)
Request (request)
SDO upload expedited response Answer (response)
SDO upload normal request 5 … 1,406 bytes of
usage data (nor­
mal)
Request (request)
SDO upload normal response Answer (response)
Upload SDO segmented request 1,407 … n bytes of
usage data
1)
(seg­
mented)
Request (request)
Upload SDO segmented response Answer (response)
1) The usage data are fragmented into packages, each of max. 7 bytes.
Tab. 3.43 SDO Services: Read out parameter data
Note
The answer (upload ... response) from the EMCA must be waited for in any event!
The next SDO request cannot be transmitted until the EMCA has answered the read
command.