Chapter 11 DeviceNet Master Scanner Module AS01DNET-A
11-17
1
Position of
AS01DNET
on the right
of the PLC
Output mapping area (for sending data to
Input mapping area (for receiving data from
D register Mapping area
Data
D register Mapping area
Data
output data
words data area words
Note: See Section 11.4.5 for further explanation of scan-list node status indication areas and module status indication
areas. The input and output mentioned here are defined in the perspective of the master of the entire fieldbus system.
When AS01DNET works in slave mode, the input and output mapping areas for AS01DNET at different positions
of the right of AS PLC are listed in the following table.
AS01DNET on
the right of the
Area for sending data to the master Area for receiving data from the master
D register Data length D register Data length
1
D26100~D26199 100 words D26000~D26099 100 words
2
D26500 – D26599
100 words
D26400 – D26499
100 words
3
D26900 – D26999
100 words
D26800 – D26899
100 words
4
D27300 – D27399
100 words
D27200 – D27299
100 words
11.4.4 Bit-strobe Command
11.4.4.1. Bit-strobe Work Principle
Bit strobe is one of the standard DeviceNet I/O transmission methods. The command length is fixed to 8 bytes, i.e. 64
bits. (Maximum 64 stations exist in a DeviceNet network.) One bit corresponds to one node. The following table takes
the first AS01DNET on the right of AS PLC for example.
Bit-strobe
register
Corresponding network node
Node 47 Node 46 Node 45 … … Node 33 Node 32
Node 63 Node 62 Node 61 … … Node 49 Node 48
When the value of bit0 of D26100 is 0, node 0 is selected and need return data to the master.
When the values of bit0 and bit1 of D26100 are both 0, node 0 and node 1 are selected and they need return data to the
master.
b0b1b17 b15 b14b30 b2b18 b16b31
D6283
Node 0
Node 1
Node 2
Node 14
D6282
In the bit-strobe method, the master does not send control data to the slave node. However, the slave node need return
I/O data to the master if the corresponding bit is set to 0. If the corresponding bit is set to 1, the slave node does not need
to return I/O data to the master.
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