![Anybus CompactCom 40 EtherNet/IP Network Manual Download Page 189](http://html1.mh-extra.com/html/anybus/compactcom-40-ethernet-ip/compactcom-40-ethernet-ip_network-manual_2948758189.webp)
Doc.Id. HMSI-27-212
Anybus CompactCom 40 EtherNet/IP
Doc.Rev. 1.5
Appendix C
C. Message Segmentation
C.1 General
Category
: Extended
The maximum message size supported by the Anybus CompactCom 40 is 1524 bytes. If the host appli-
cation implements a data message size of 1524 bytes, a message will always fit into one segment. The
host application can implement a shorter data message size (255 bytes for backwards compatibility with
the 30-series).
No service requires messages larger than what is supported by the Anybus CompactCom 40 series 1524
bytes messaging interface. If this interface is used by the application, it allows very basic segmentation
handling. The first segment bit (FS) and the last segment bit (LS) shall always be set in each segmented
command or response. In the Anybus CompactCom 40 series, some commands in the Socket Interface
Object (page 109) and in the EtherNet/IP Host Object (161) use segmentation.
If a shorter message size is implemented, segmentation has to be used, setting the FS bit in the first seg-
ment of the message sent, and setting the LS bit in the last segment sent.
The segmentation protocol is implemented in the message layer and must not be confused with the frag-
mentation used on the serial host interface. Consult the general Anybus CompactCom 40 Software De-
sign Guide for further information.
The module supports 20 simultaneous segmented messages.