Physical or logical addressing of inputs/outputs
(Original Document)
About us
At a Glance
Inputs/outputs respect the topology used by the Control Expert software and can be identified:
Topology
Addressing is defined in the following way:
%
I or Q
X, W or D
r
.
m
.
c
.
d
.
j
.
Symbol
Type of objects
I = input
Q = output
Format
X = Boolean
W = word
D = double word
Rack address
r = 0 to 7
Module position
y = 0 to 14
Channel no.
c = 0
Position
r = 0 to 253
bit
j = 0 to 15
Block assignment
DP data is exchanged in the form of input/output blocks. All slave input data is indexed by adjacent %IW blocks. Slave output data is indexed by adjacent %QW blocks. The continuity of %IW and %QW blocks is valid even for a modular slave.
Each data block for a slave starts with a new %IW or %QW. As a result, the first I/O word of a slave is always associated to a new %IW or %QW.
In the event where a slave image (%IW or %QW) has a special size (for example 1 byte or 3 bytes), it is completed by unused bytes in order to manipulate the I/O words.
Example
The table below describes an example of assignment:
Input image
Slave 2
2 words
Slave 1
1 byte
Unused byte
Slave 17
1 word
%IWr.m.0.d
%IWr.m.0.d+1
%IWr.m.0.d+2
Only bits 0 to 7 are significant
%IWr.m.0.d+3
Output image
Slave 17
2 words
Slave 2
1 byte
Unused byte
%QWr.m.0.d
%QWr.m.0.d+1
%QWr.m.0.d+2
Only bits 0 to 7 are significant