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2. PERFORMANCE SPECIFICATIONS
2.1 Performance Specifications
2.1.1 A1SCPUC24-R2 Module Performance Specifications
The memory capacity, device performances and other specifications of 
A1SCPUC24-R2 module are provided below.
*1 The maximum total memory that can be used for parameters, T/C set values, 
program capacity, file registers, number of comments, sampling trace, and 
status latch is 32k/64k bytes. 
The memory capacity is fixed. No expansion memory is available. 
Section 4.1.7 shows how to calculate the memory capacity.
Table 2.1 Performance specifications
Type
Item
A1SCPUC24-R2
Control system Repeated operation (using stored program)
I/O control method Refresh mode/Direct mode selectable
Programming language
Language dedicated to sequence control. Relay symbol type 
and logic symbolic language, MELSAP-II (SFC) (for A1SCPU)
Processing speed 
(sequence instruction)
Direct
Refresh 
: 1.0 to 2.3 µs/step
: 1.0 µs/step
Number of I/O points 256 points (32 points are used for the computer link function)
Watchdog timer (WDT) 10 to 2000 ms
Memory capacity *1 (built-in 
RAM)
32k bytes
Program 
capacity
Main sequence Max. 8 k steps
Sub sequence None
Self-diagnostics functions
Watchdog error monitor, Memory error detection, CPU error 
detection, I/O error detection, Battery error detection, etc.
Operation mode at the time of 
error
STOP/CONTINUE
Start method at the time of 
RUN
Initial start
(Automatic restart by turning on the "RUN" switch of the CPU 
after power-ON/recovery from power failure)
STOP → RUN output mode
Output data at time of STOP restored/data output after 
operation execution
Clock function
Year, month, day, hour, minute, second (Automatically 
recognizes leap years.)
Accuracy −2.3 to +4.4 s (TYP. +1.8 s)/d at 0 °C
−1.1 to +4.4 s (TYP. +2.2 s)/d at 25 °C
−9.6 to +2.7 s (TYP. -2.4 s)/d at 55 °C
Allowable momentary power 
interruption time
Depends on power supply module
Current consumption (5 V DC) 0.56 A
Weight 0.41 kg
Standard UL/CSA