Introduction
Almost all CANopen masters from Beckhoff offer the so-called CAN interface. The CAN interface is a Layer-2 implementation of the CAN interface. It enables any desired CAN telegrams to be received and transmitted. The higher-level protocol is not important here, i.e. all CAN-based protocols can be used; however the protocol part must then be implemented in the PLC.
The CAN interface consists of a buffer that is processed cyclically. The buffer can contain 1 to 32 data telegrams.
The transmit buffer (Tx) contains the data to be transmitted and the receive buffer (Rx) the data that have been received. 11-bit or 29-bit messages can be received or transmitted, depending on the CAN master. The buffer is processed with the cycle time of the task. With a buffer size of 10, therefore, a maximum of 10 CAN telegrams can be transmitted or received per task cycle.
11-bit identifier, also known as "Base Frame Format" (CAN 2.0A)
29-bit identifier, also known as "Extended Frame Format" (CAN 2.0B)
CAN interface – supported functions
| CAN2.0A | CAN2.0B | CAN FD | Fast | Optimized | Time Stamp2 | |
|---|---|---|---|---|---|---|---|
EL6751 | ✔ | ✔ | - | - | ✔ | ✔3 | - |
EL6751 | ✔ | ✔ | - | ✔ | ✔ | ✔ | - |
EL6753 | ✔ | ✔ | ✔ | - | - | ✔3 | ✔ |
CCAT | (✔)4 | ✔ | - | - | - | ✔ | ✔ |
CX1500-M510 | ✔ | ✔ | - | - | - | - | - |
FC510x, | ✔ | ✔ | - | - | - | - | - |
FC532x, | ✔ | ✔ | ✔ | - | - | ✔ | ✔ |
1) | not in 29-bit mode, not with Transaction Number |
2) | only in 29-bit mode and with Transaction Number |
3) | only in 29-bit mode |
4) | covered by the 29-bit ID option |
5) | in preparation |
 | CCAT What is CCAT? Which Beckhoff products is it backed by? The CCAT interface is the Beckhoff company's current CAN implementation and is used by the Beckhoff PCI-Express cards and the onboard interfaces of the Beckhoff Embedded PCs. These are, for example, the following products and only available for the CANopen Master: |