Communication protocol 113Process Data Objects (PDO)Process Data Object (PDO) is used for time critical process dataexchange. PDO transmissions can be controlled by an internaltimer, by remote requests or by the received Sync message. Foreach PDO the transmission mode of the PDO as well as thedefault mappings of the application objects are described in theObject Dictionary. The adapter module supports also configurationof the PDOs with drive parameters.The adapter module supports a maximum of three PDOs in bothdirections. By default only Tx PDO1 and Rx PDO1 are enabled(valid) and Tx/Rx PDO6 and Tx/Rx PDO21 are disabled (not valid).PDO mapping defines which application objects (parameters) aretransmitted within a PDO. PDO mappings of the adapter modulecan be changed in the Pre-operational state (variable objects).Transmission of the enabled (valid) PDOs is possible only in theOperational state.Each PDO can contain up to 8 bytes of process data. In ACS355,the first mapping entries of Tx/Rx PDO1 and Tx/Rx PDO6 are fixedand cannot be changed. The length of the PDOs and mappingentries of the PDOs are configurable.The mapping entries of the PDOs can be configured throughCANopen objects or from the drive with fieldbus configurationparameters. The configuration location is selected from the drivewith parameter 04 CONF LOC of the fieldbus configuration groupA (group 1) (parameter 51.04 in ACS355, ACSM1, ACS850 andACS880).When mapping through CANopen objects, the PDO length must beset to zero before the mapping entries can be changed.
