Yaskawa 120 Series I/O Modules - Manual (Page 119)

3.4 I/O Allocation
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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 input relays and input registers.
(1) When 64-point input relays are allocated from 100001, the bit order can be set
to either “MSB” or “LSB,” as described in the following table and shown in the
illustration below it. Allocation is performed in units of 16 input points.
Refer to Fig. 3.5 Allocation of Input Relays for details.
(2) When four input registers starting from 300001 are allocated, the bit order can
be set to either “MSB” or “LSB,” as described in the following table and shown
in the illustration below it. Allocation is performed in units of 16 input points.
Refer to Fig. 3.6 Allocation of Input Registers for details.
Input Relay MSB Setting The leading input reference number (100001) is allocated to the
smallest input number (input 1) of the first 16 points on the Input Mod-
ule, and then the next input reference number (100017) is allocated to
the smallest input number (input 17) of the next 16 points.
Input Relay LSB Setting The leading input reference number (100001) is allocated to the larg-
est input number (input 16) of the first 16 points on the Input Module,
and then the next input reference number (100017) is allocated to the
largest input number (input 32) of the next 16 points.
Input Register LSB Setting Bit 15 (MSB) of the leading input register (300001) is allocated to
the smallest input number (input 1) of the first 16 points on the
Input Module, and then bit 15 (MSB) of the next input register
(300002) is allocated to the smallest input number (input 17) of
the next 16 points.
Input Register MSB Setting Bit 15 (MSB) of the leading input register (300001) is allocated to
the largest input number (input 16) on the Input Module, and then
the bit 15 (MSB) of the next input register (300002) is allocated to
the largest input number (input 32) of the next 16 points.