Selection of process data
The process data of the EL3356 are set up in the TwinCAT System Manager. The PDOs can be activated or deactivated separately. The ‘Process data’ tab is used for this (visible only if the terminal is selected on the left).

If the terminal is selected in the System Manager (A), the Process data tab (B) shows the PDO selection. The two SyncManagers of the inputs (SM3) and outputs (SM2) can be changed (C). If one of the two is clicked on, the PDO possible for this SyncManager appears underneath it (D). PDOs that are already activated have an activated checkbox in front of them; this is activated by clicking on it.
The process data which then belong to the device are listed underneath it (G). So that the individual bit meanings are visible, e.g. in the Status status word, and can be separately linked (G), ShowSubVariables must be activated in the System Manager (F). The bit position at which the subvariables are located in the status or control word Ctrl) can be taken from the address overview (H) or the following information.
Predefined PDO Assignment
In order to simplify the configuration, typical configuration combinations of process data are stored in the device description. The predefined configurations can be selected in the process data overview. Therefore the function is available only if the ESI/XML files are saved in the system (downloadable from the Beckhoff website).
The following combinations are possible (see also Fig. EL3356 process data selection in the TwinCAT System Manager, E):

- Standard (INT32): [Default setting] load calculation; 32-bit integer load value as final value according to the calculation specifications in the CoE, no further conversion necessary in the PLC
- Standard (REAL): Load calculation; 32-bit floating-point load value as final value according to the calculation specifications in the CoE, no further conversion necessary in the PLC
- 2x AnalogIn (Standard): 2-channel voltage measurement, 32-bit integer voltage value with additional information (under-range, over-range, error, TxPDO Toggle)
- 2x AnalogIn (Compact): 2-channel voltage measurement, 32-bit integer voltage value only