Packing digital signals
EtherCAT Terminals generally always require 1 full byte for process data. 1 full byte for process data is also assigned for EtherCAT Terminals, which effectively only have a process data size of 2 or 4 bits.
In order to fill 1 byte completely, the 2- or 4-channel EtherCAT Terminals can be packed. Please ensure that these EtherCAT Terminals are connected successively and that 1 byte is not exceeded.
The entry EL1xxx or EL2xxx in the GSD file is used for this purpose. The EtherCAT Terminals to be packed have the entry EL1xxx (pack) or EL2xxx (pack). These EtherCAT Terminals then have no data. The data are added to the preceding terminals in the byte.
Example:
Three EL1002 (each with 2 channels) are connected consecutively. In this example one EL1xxx can be configured and two EL1xxx (pack).
The process data for these EtherCAT Terminals then are as follows:
First EL1002: | x.0 and x.1 |
Second EL1002: | x.2 and x.3 |
Third EL1002: | x.4 and x.5 |
Requirements
- The EtherCAT Terminals must be connected consecutively.
Pack digital signals as follows:
- 1. Right-click on Box 1 (GSD) (EK3100) on the left in the tree view.
- 2. Click on Add New Item in the context menu.
The Insert Module window appears.
- 3. Select the terminal EL1xxx.
The EtherCAT Terminal is added in TwinCAT. - 4. Then select the terminal EL1xxx (pack) and enter the value "2" under the option Multiple.
- Three EL1002 EtherCAT Terminals were added in TwinCAT. The data of the two EL1xxx (pack) are added to the preceding EtherCAT Terminal in the byte.
In the example a further EL1002 can be connected to fill the byte. Or other 2-channel input terminals can be used. It is important that they have the same mapping. It is also possible to mix 2-channel and 4-channel EtherCAT Terminals, as long as 1 byte is not exceeded.