Omron GRT1 - 11-2007 Operation Manual page 36

Unit Numbers and I/O Allocations
I/O Allocation
Example
Commu-
nications
Unit
Input Area
Word
15 8 0
First Word
Communications Unit Status
+1 #3 #2 #1
Unused
+2
#4
+3
Unused
+4 #5
Some areas may be unused when data is allocated.
Note
Communi-
cations
Unit
I/O data is allocated to the I/O Units in the order that they are connected to the
Communications Unit, regardless of the I/O Units' models. Unless special
allocation data settings are selected with the Communications Unit's Pro-
gramming Device, data is allocated from the first word starting with the Com-
munications Unit's Status Flags and then the leftmost I/O Unit's data.
Data in the Master's Input and Output Areas is allocated to the Slice I/O Units
based on their unit numbers.
#1 #2 #3 #4
ID4 ID4 ID4 AD2
I/O Units with bit allocations (such as the GRT1-ID4/OD4) are allocated data
in 2-bit units. I/O Units with word allocations (such as the GRT1-AD2) are allo-
cated data in 1-word units. The following example shows the allocations to
Output Units.
Slice I/O Terminal Configuration
#1 #2
OD4 OD4 OD4
Word
+0
+1
+2
+3
+4
+5
#5 #6 #7 #8
ID8 OD4 ROS2 OD8
#3 #4 #5
ROS2 OD4
Data is allocated in 2-bit units
to I/O Units that require 4 bits,
so there may be unused areas
as shown in the following table.
8
15
0
# #
#3 #2 #1
5 4
#
Unused
5
#6
#7
Unused
Unused #8
Data in these areas will not be output.
Section 2-2
#9
OD4
Output Area
15 8
#7 #6
Unused
First Word
+1 #8
Unused
+2 #9
Unused
#6 #7 #8
DA2 OD4 OD8
0
15