3process data objects – West Control Solutions KS 800 CANopen Interface Manual User Manual
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KS 800 CAN-Interface
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Process data objects
Max. 4 bytes of usable data can be transmitted between two partners by means of SDOs. The
remaining 4 bytes are used for the command, the index and the subindex. With one PDO, howe-
ver, max. 8 bytes of usable data can be transmitted. Two send and two receive PDOs, which can
be defined as "synchronous PDOs" or as "asynchronous PDOs" via configuration, are supported
by KS800. For instance, the data transfer via the PDOs is purposeful, when controller process
values and status values must be sent to the master dependent of e.g. error messages (change-
of-state). In this case, asynchronous PDOs, which will be sent to the master automatically when
the event occurs on the controller are used. Another example would be cyclic enquiry of process
values by an operating unit. In this case, KS800 can send PDOs by synchronization with a clock
frequency (SYNC-EVENT).
As opposed to SDOs, PDOs are always non-acknowledged services. They can be received by
several units. As already mentioned above, this does not apply to SDOs.
In the KS800 default configuration, one asynchronous send and receive PDO with the following
identifiers are enabled:
COB-ID of the asynchronous receive PDO:
0x200 + node ID
COB-ID of the asynchronous send PDO:
0x180 + node ID
PDO reconfiguration is possible by means of SDO accesses to the following indexes:
default
default COB-ID
Index 1400:
first receive PDO
sync./disabled
300
Index 1401:
second receive PDO
async./enabled
200
Index 1800:
first send PDO
sync./disabled
280
Index 1801:
second send PDO
async./enabled
180
Configuration of the message identifier (COB-ID) as well as PD0 enabling and disabling are done
under subindex 1.
COB-ID (low byte)
data[ 1]
COB-ID (high byte)
data[ 2]
Enable
data[ 4]
(0x00 = enabled, 0x80 = disabled)
Transfer type configuration is under subindex 2.
Transfer type
data[ 1]
(0x01...0x0F = synch, 0xFF = async)
The PDO data contents are described in the following section.
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