I/O control method: refresh mode or direct mode.
User program storage capacity: 8K step.
I/O points: 256 points.
Memory capacity: bytes 64K.
ANSCPU has been updated to ANSHCPU, and it has the following advantages.
16 bit dedicated microprocessor.
Large capacity battery backup memory RAM.
Extended I/O control capability AJ71QBR11  Hardware Manual AJ71QBR11  User's Manual.
Dedicated CC-Link instruction AJ71QBR11 
Capacity for extended comment storage.
Write speed processing. Data format: RTU.
Data bits: 8.
A1SJ71UC24-R2-S2 and A1SJ71UC24-R4-S2 allow the Ans series PLC to be connected to the MODBUS network,
As the network from the station, and in accordance with the instructions of the main station of the CPU Ans user storage area for data reading / writing AJ71QBR11  Hardware Manual AJ71QBR11  User's Manual.
In addition to supporting the MODBUS protocol, these components also support the standard dedicated communication protocol for A1SJ71UC24 components.
This feature makes the main station of the data acquisition and control with more flexibility.
Support MODBUS slave station protocol.
Supports 1 to 21 function code.
Two transmission modes: RTU or ASCII. 2 slots.
Can be installed in the power supply unit for A series units installed QnA/ AJ71QBR11  Hardware Manual AJ71QBR11  User's Manual.
Cannot extend.
Relay output interface circuit of PLC
Working process: when the internal circuit output digital signal 1,
There is a current flowing through, the relay coil has a current, and then the normally open contact is closed,
Provide load current and voltage.
When the internal circuit outputs a digital signal 0, there is no current flowing through it,
The relay coil does not have a current, and the normally open contact is broken off,
A current or voltage that is disconnected from the load.
It is through the output interface circuit to the internal digital circuit into a signal to make the load action or not action.
I/O points is an important indicator of PLC.
Reasonable selection of I/O points can not only satisfy the control requirements of the system,
And the total investment of the system is the lowest.
The input and output points and types of PLC should be determined according to the analog quantity and switch quantiity of the controlled object,
Generally an input / output element to take up an input / output point AJ71QBR11  Hardware Manual AJ71QBR11  User's Manual.
Taking into account the future adjustment and expansion,
In general should be estimaated on the total number of points plus the amount of spare 20%~30% AJ71QBR11  Hardware Manual AJ71QBR11  User's Manual.
The following describes the centralized control system I/O points of the estimate.