Festo SFC-DC series, Manual

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B. Supplementary information
B−3
Festo P.BE−SFC−DC−IO−EN en 0801a
B.1 The Command Interpreter (CI)
The commands implemented in the Command Interpreter of
the SFC−DC are based in respect of their content on the Ob
jects standardized by CANopen (CiA Draft Standard 402):
Group 1xxx
Device description
Group 2xxx Festo commands
Group 6xxx Commands as per CANopen
The CiA Draft Standard 402: deals with the concrete imple
mentation of CANopen in drive controllers.
Object directory The total of all parametrizing and control possibilities is re
ferred to as the Object directory. Access can be made to the
Object directory of the controller via Service Data Objects
(SDO). SDOs are used for normal parametrizing of the con
troller. Access to the SDOs is always made from the higher−
order controller (host). A clear number (index, subindex) is
assigned to each Object.
Access procedure The higher−order controller sends the controller either a write
command (WRITE) in order to modify a parameter of the Ob
ject directory, or a read command (READ) in order to read out
a parameter.
For each command the higher−order controller receives a
reply which either contains the value read or, in the case of a
write command, serves as an acknowledgement. The trans
ferred value (1, 2 or 4 data bytes) depends on the data type
of the Object to be read or written.
As from version 1.10, the firmware of the SFC−DC offers the
possibility of simulating SDO access with CI commands via
the RS232 interface.