Lenze DDS System bus CAN for PLC - Manual (Page 31)

System bus (CAN) for Lenze PLC devices
General information
2−19
l
PLC−Systembus EN 2.0
2.8 Free CAN objects
If many nodes are connected to the system bus (CAN), it may occur that the CAN objects
(CAN1_IO ... CAN3_IO) which are fixedly integrated in the PLC are not sufficient for the
communication intended, and further CAN objects are required.
By using the functions/function blocks of the LenzeCanDrv.lib function library, so−called "free CAN
objects" can be added to the fixedly integrated CAN objects.
( ^ 10−2)
Characteristics of the free CAN objects
Free CAN objects
User data per object 1 ... 8 byte
Intended use Transmission of parameter and process data
Transmission modes
·
Event−controlled transmission
·
Time−controlled transmission
·
Time−controlled transmission with superimposed event control
·
Forced transmission
Range for identifiers Transmission and reception identifiers can be allocated in the range of 0 ... 2047, but they have to differ from the
identifiers of the integrated CAN objects.
Note!
The free CAN objects are processed via a so−called transmit request memory by the operating
system, i. e. the transmission process is not carried out immediately when the L_CanPdoTransmit
FB is called, but is effected in a delayed manner.
( ^ 10−8)
The transmission and reception jobs of the free CAN objects are not linked to the process image.