PDO Mapping

As already explained, all 8 data bytes of a CAN message are available for the transmission of process data. As there is no additional protocol information, the data format has to be agreed between the sending (producer) and the receiving party (consumer). This is done by the so-called PDO mapping.

If a fixed mapping is used, the process data are arranged in a pre-defined order within the PDO message. This arrangement is predetermined by the device manufacturer and cannot be changed. If variable mapping is used, the process data can be arranged as desired within the PDO message. For this purpose, the address, consisting of index and sub-index, as well as the size (number of bytes) of an object directory entry are entered into the mapping object.