Omron CQM1 Operation Manual page 69

Word Allocation
50
Connect the transmission cables in series from the Master, regardless of the
Unit number settings.
CQM1H/CQM1
Unit
Input word
Output
word
Expansion Masters Mounted Left of the Master
Take care of the allocation of Master, Expansion Master Unit 1 and Unit 2
word addresses.
If one Expansion Master is used for input and another for output, take care
that the Expansion Master Unit numbers and the Unit 1/Unit 2 Slave address
settings are not reversed.
A 4-point Slave cannot be used as a Unit 2 Slave address.
Connect the transmission cables in series from the Master.
CQM1H/CQM1
Input word
Output
word
I/O Input
16 16
points points
Input
16 16
points points
Unit
Section 4-1
Input
Output I/O