Lenze DDS System bus CAN for PLC - Manual (Page 21)

System bus (CAN) for Lenze PLC devices
General information
2−9
l
PLC−Systembus EN 2.0
2.6.2 Sync telegram for cyclic process data
For the transmission of cyclic process data, a specific telegram − the sync telegram − is required for
the synchronisation.
The sync telegram which has to be generated by a different node initiates the transmission process
for the cyclic process data of the PLC and at the same time is the trigger point for the data acceptance
of the cyclic process data received in the PLC:
Sync telegram Sync telegram
CAN1_OUT CAN1_IN
1. 2. 3. 4.
Fig. 2−4 Synchronisation of the cyclic process data by a sync telegram (without considering the asynchronous data)
1. After a sync telegram has been received, the cyclic process output data (CAN1_OUT) are sent
by the PLC if "respond to sync" has been activated.
2. When the transmission process has been completed, the cyclic process input data (CAN1_IN)
are received by the PLC.
3. The data acceptance in the PLC is effected with the next sync telegram.
4. All further telegrams (e. g. for parameters or event−controlled process data) are accepted in an
asynchronous manner by the PLC after transmission has been completed.
Tip!
The response to a sync telegram is configured via the following codes:
·
for CAN1_OUT via C0366. ( ^ 3−7)
·
for XCAN1_OUT ... XCAN3_OUT via C2375. ( ^ 4−7)
·
for FIF−CAN1_OUT via C2466. ( ^ 5−7)
·
for CANaux1_OUT via C2466. ( ^ 5−7)
Also the telegrams of CAN2_OUT and CAN3_OUT can be transferred after a sync telegram, the
parameterisation of this function is carried out via the CAN_Management SB.
( ^ 7−20)