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 11 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 | ✔ | ✔ | - | ✔ | ✔ | ✔ | - |
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: |