Specifications

Fieldbus Communications Support
64
31004624 8/2009
Input and Output Data Exchange
The application of the INTERBUS bit packing rules to the sample island
(see page 78) assembly (in the Applications Example chapter) will result in 4 words
of output data and 10 words of input data. The tables that follow show how digital
data is bit packed for optimization, and how data, status, and echo output data (from
outputs) appear in the PLC as the same data type (digital input data). In these
tables, N refers to the island node number. That is, N1 represents the first
addressable node (module) on the sample island bus, N2 the second, and so forth.
Output Data Exchange
The following table shows how the 4 words of the sample island (see page 78)
assembly output data process image are organized after applying the bit packing
rules:
Input Data Exchange
The following table shows how the 10 words of the sample island (see page 78)
assembly output data process image are organized after applying the bit packing
rules (the first word contains the NIM status):
Bit Number
Word 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 NIM control word
2 empty (set to 0) N6 output data N4 output data N2 output data
3 N8 (channel 1) analog output data
4 N8 (channel 2) analog output data
Bit Number
Word 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 NIM status
2 N3 input status N3 input data N2 output
status
N2 output
echo
N1 input
status
N1 input
data
3 empty (set
to 0)
N5 input data N4 output status N4 output echo
4 empty (set to 0) N6 output echo N5 input status
5 empty (set to 0) N6 output status
6 N7 (channel 1) analog input data
7 empty (set to 0) N7 (channel 1) analog input status
8 N7 (channel 2) analog input data
9 N8 (channel 1) analog output status N7 (channel 2) analog input status
10 empty (set to 0) N8 (channel 2) analog output status