EtherNet/IP adapter functionality
10
3
EtherNet/IP adapter functionality
3.1
Message Server
The EtherNet/IP stack in the BG02-EIP provides EtherNet/IP adapter functionality. No outbound
connection capability or outbound UCMM client services are implemented. The following “Level 2”
adapter class functionality is provided:
-
UCMM Message Server
-
Class 3 Message Server for up to 32 class 3 connections (limit configurable)
-
Class 1 Message Server for up to 31 class 1 connections (limit configurable)
The Class 1 message timing resolution is 1 ms. The minimum allowed Requested Packet Interval (RPI)
is 20ms!
3.2
Process Data Mapping
Process data is exchanged by reading/writing assembly instance 103, attribute 3 (as defined by the
standard). The size of the attribute data is fixed 384 bytes (for reading and writing). The actual size of
the process data image is defined in the KE’s PLC assignment table and copied into the CIP object
buffer. However, the actual process data image is mapped to a fixed area in the CIP assembly object
(reserved range is byte 0…239, i.e. max 240 bytes). The rest of the area (bytes 240…383) is reserved
for status data. Please see the following figure for the general layout (note: “In” refers to PLC writing
to BG02, “Out” refers to PLC reading from BG02):
Byte[0]
Byte [1]
… Byte [239] Byte[240]
…
Byte[383]
In
process data (to KE)
unused (should be zero)
[0]
[1]
[239]
Out
process data (from KE)
diagnostics data
[0]
[1]
[239]
[0]
*…+
There is no need to configure the SMpdp module inside the KE/SE to always transmit 240 bytes, just
use as much data as is required for the process. The BG02 automatically adjusts its configuration to
