Beckhoff FC5101, Документация

Страница: 49 / 100

CANopen Communication
FC5101 and FC5102 49 Version: 2.0
Event Timer
An event timer for transmit PDOs can be specified by sub-index 5 in the communication parameters. Expiry
of this timer is treated as an additional event for the corresponding PDO, so that the PDO will then be
transmitted. If the application event occurs during a timer period, it will also be transmitted, and the timer is
reset.
Fig. 41: Time representation of the event timer
In the case of receive PDOs, the timer is used to set a watchdog interval for the PDO: the application is
informed if no corresponding PDO has been received within the set period. The FC510x / EL6751 can in this
way monitor each individual PDO.
Notes on PDO Parameterization [
}
51]
PDO Mapping
PDO mapping refers to mapping of the application objects (real time data) from the object directory to the
process data objects. The CANopen device profile provide a default mapping for every device type, and this
is appropriate for most applications. Thus the default mapping for digital I/O simply represents the inputs and
outputs in their physical sequence in the transmit and receive process data objects.
The default PDOs for drives contain 2 bytes each of a control and status word and a set or actual value for
the relevant axis.
The current mapping can be read by means of corresponding entries in the object directory. These are
known as the mapping tables. The first location in the mapping table (sub-index 0) contains the number of
mapped objects that are listed after it. The tables are located in the object directory at index 0x1600ff for the
RxPDOs and at 0x1A00ff for the TxPDOs.