Bit assignment
Technical manual LioN-Link BusHead EtherNet/IP™
Release 1.1 04/2016
7.1 Input data – Assembly instance
101
45
7 Bit assignment
The LioN Link BusHead uses assembly instances to exchange cyclical I/
data. The BusHead supports:
Assembly instance
101
for inputs and
Assembly instance
100
for outputs.
The BusHead provides 2 bytes of input 2 bytes of output data. These data act
as status and control bytes for special functions (diagnose acknowledge,
transmission of acyclical parameter data, etc.). In process data transmission,
the device first transmits the analog data and then the digital data. The
process image from or to the controller is always composed wordwise (word
alignment). The device always transmits analog word data in Little-Endian
format.
7.1
Input data – Assembly instance 101
The following example shows the input data mapping. The BusHead
composes the process image for the input data based on the following rules:
All analog input data (word alignment)
All digital input data (word alignment, a byte is transmitted as a word)
BusHead status data (2 bytes)
All diagnostic data, depending on the setting:
– 2 blocks (2 × 4 bytes = 8 bytes) or
– 6 blocks (6 × 4 bytes = 24 bytes)
The following example shows the input data mapping:
Byte
Data
0
UEM630 Ch. 1, Analog in low byte
1
UEM630 Ch. 1, Analog in high byte
2
UEM630 Ch. 2, Analog in low byte
3
UEM630 Ch. 2, Analog in high byte
Table 9:
Input data – Assembly instance 101
