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DeviceNet (MCW151-DRT-E only)
Section 4-2
Note The names of the input and output areas indicate the direction of I/O from the
perspective of the Master.
Allocating Input and
Output Areas to the
Master
The MC Unit’s input and output areas are allocated to the Unit as a DeviceNet
Slave in the Master’s I/O memory.
■
Fixed Allocation
With fixed allocation, words in the CPU Unit are allocated in the order of node
numbers starting from node 00. The words are divided into an output area and
an input area. The specific words that are allocated depend on the model of
PC being used.
Each node address is allocated one input and one output word. If a Slave
requires more than one input or one output word, then it is assigned more
than one node address. If a Slave requires less than one word, it simply uses
the rightmost bits in the word allocated to it.
The MC Unit will occupy the number of words (number of node numbers) set
for the input and output areas using the external DIP switch pin 7.
For example when the MC Unit has been selected to Mode II and the node
number is set to 5, the input area will occupy the words for nodes 5 through 8
and the output area will also occupy the words for nodes 5 through 8.
■
Free Allocation
A Configurator can be used to allocate a total of 4 blocks, blocks 1 and 2 in
the output area and input blocks 1 and 2 in the input area in any order.
Slaves and blocks can be allocated in any order. The number of words (num-
ber of bytes) that are used depends upon the addresses. The minimum is one
byte and the maximum is 64 bytes (32 words).
Pin 7
Mode
Description
OFF
Mode I (default)
Input:
2 words
Output: 2 words
ON
Mode II
Input: 4
words
Output: 4 words