Siko AG06 - 9.3.4 Process Data Objects (PDOs)

Communication via CAN bus
AG06 Date: 07.02.2018 Art. No. 85674 Mod. status 055/18 Page 39 of 114
9.3.4 Process Data Objects (PDOs)
Process data objects serve for fast exchange of short process data. Process data objects are
transferred event-triggered, cyclically or on request. A maximum of 8 bytes of user data can
be transferred in a PDO.
The exchange of PDOs is enabled in the NMT status Operational only!
The actuator provides 3 Transmit PDOs (process data from the actuator  NMT master) and 3
Receive PDOs (process data from the NMT master  to the actuator). The Receive PDOs,
RPDO1, RPDO3, RPDO4 and the Transmit PDOs, TPDO1, TPDO3 and TPDO4 are supported
according to the Device Profil 'Drives and Motion Control CIA DSP-402 Version 2.0'.
9.3.5 Transmit-PDOs
9.3.5.1 1
st
Transmit PDO (TPDO1)
The first Transmit PDO contains 2 user data bytes on which the status word of the actuator is
mapped.
The Transmit PDO is transferred by the actuator asynchronously as a standard. Together with
the Receive PDO1 on which the control word of the state machine is mapped it forms a
handshake connection (acknowledgement operation) between the higher-order control and
the drive controller.
It is, therefore not recommended to change the transfer type of the TDO1.
The COB-ID of the first Transmit PDO is programmed to 180
h
+ Node-ID by default. The
communication parameters are set via the object 1800
h
(1
st
Transmit PDO parameter).
1
st
Transmit PDO
11/29 Bit Identifier
Byte 1
Byte 2
LSB
MSB
Status word (object 6041
h
)
Table 17: 1
st
Transmit PDO
9.3.5.2 3
rd
Transmit PDO (TPDO3)
The third Transmit PDO contains 6 user data bytes on which the status word and the current
position value of the actuator are mapped.
The Transmit PDO3 is transferred only by a RTR frame (remote transfer request) as a standard,
i. e., a higher-order control must request the TDO3 (polling). Synchronous transfer (value 0 to
240) can be set via the SYNC object or the time-triggered transfer (value 255) by means of a
local cycle (event timer) as an alternative to polling.
The COB-ID of the third Transmit PDO is programmed to 380
h
+ Node-ID by default. The
communication parameters are set via the object 1802
h
(3
rd
Transmit PDO parameter).