3.4 I/O Allocation
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3
2) Module Type Setting
The type of Output Module mounted in the slot is set as the Module type. Only the
last 11 alphanumeric characters of the model number are necessary. For example
120DAO84300 is the Module type for the JAMSC-120DAO84300.
3) I/O Reference Number Setting
(a) The leading I/O reference number used by the Output Module is set.
(b) Any one of the I/O reference numbers and points listed in the following table
can be set.
(c) When an output coil is set, the leading I/O reference number must satisfy the
following equation:
Leading reference number of I/O coil = 16 n
where n = 0 to 63 for the CPU20 and
n = 0 to 255 for the CPU30
For example, 000001 can be set as the leading reference number, but
000002 cannot.
4) I/O Data Format
The following items can be set to define the I/O data format. There is, however, gen-
erally no need to change these settings because the default settings can be used
for most normal applications.
a) Bit Order
I/O can be processed by handling data either in ascending or descending order of
the bits. This is explained next for allocation of both output coils and output regis-
ters.
(1) When 16-point output coils are allocated from 000001, the bit order can be set
to either “MSB” or “LSB,” as described in the following table and shown in the
illustration below it.
Refer to
Fig. 3.9 Allocation of Output Coils
for details.
Type of Output
References for I/O Allocation
Points/Registers
CPU10, CPU20, CPU21
CPU30, CPU35
Output coils
000001 to 001024
000001 to 004096
16 points
Output registers
400001 to 400512
400001 to 400512
1 register
Output Coil MSB Setting
The leading output reference number (000001) is allocated to the
smallest output number (output 1) on the Output Module.
Output Coil LSB Setting
The leading output reference number (000001) is allocated to the
largest output number (output 16) on the Output Module.
