Suppress publisher
Applicable: TwinCAT from version 2.11, EL6601 from FW08, EL6614 from FW04
If the EL66xx is operated with a short cycle time and with publishers configured, this can place a high loading on the connected network. For this reason, the EL66xx can be configured in such a way that the transmission of individual publishers can be blocked through the DevCtrl variable. The object 0xF800:02 must be occupied in the CoE (CanOpenOverEtherCAT) for this purpose.
Groups of publisher boxes can be blocked by setting appropriate bits (publisher frames). The topmost 4 bits (the high nibble of high byte) from 0xF800:02 specify the granularity of the groups 1..15, i.e. how many publisher frames are handled together as one group:
The upper 8 bits of DevCtrl (format: 16 bits) then block the transmission of the publisher frames located in the corresponding group in the current cycle.
High byte of DevCtrl :
- 0 = no blocking
- n = each bit in DevCtrl corresponds to a group of n publishers, where n has a value in the range [1..31]
It follows that a maximum of 8 groups of publishers can be blocked.
Sample:
DevCtrl.10 = true and 0xF800:02 = 0x2000 signifies that the third group will be blocked in this PLC cycle. One group consists of 2 publisher frames, which means that in this case all the publisher variables that are located in publisher frames 5 and 6 will not be transmitted.
Notice | |
Suppressing individual publishers The structure of a "publisher" as a publisher box in the System Manager is |
The success achieved in this way can be observed using, for instance, a network monitor such as Wireshark.
 | Changes in the CoE The CoE contents can, if writable, be changed online using the TwinCAT System Manager. However, after the terminal or the EtherCAT system is restarted, this change will no longer be present; default values will apply. As a result, any permanent change must be stored in the terminal's CoE startup list. |
Note: In this documentation, bit counting starts from 0: value.0, value.1, ...