Handling Of Input Signals Designated For High-Speed Input - Mitsubishi Electric M800VW Series Programming Manual

M800V/M80V Series PLC Programming Manual (1/2)
3 Input/Output Signals

3.2 Handling of Input Signals Designated for High-Speed Input

3.2 Handling of Input Signals Designated for High-Speed Input
The input/output signals used in user PLC are input/output for each program level as shown in the figure below.
In high-speed processing, input/output signal for which high-speed input or output designation (parameter) is made is input or
output each time the high-speed processing program runs. In main processing, signals other than the high-speed input/output
designation are input/output.
When high-speed input designation signal is used in main processing, the input signal may change within one scan because
high-speed processing whose level is higher than main processing interrupts. Input signal which must not change within one
scan should be saved in temporary memory (M), etc., at the head of main processing and the temporary memory should be
used in the main program, for example.
Input image memory
The hatched area is high-speed input designation part. Whenever the high-speed processing program runs, data is reset in
the hatched area. Thus, the signal in the hatched area may change in main processing (A) and (B) because the high-speed
process interrupts between (A) and (B) and re-reads the input signal in the hatched area.
Main processing
A
(1)
High-speed
processing
(2)
(1) Set at the head of main processing.
(2) Set at the head of high-speed processing.
17
PLC one scan
B
IB-1501667-B