Input/Output Signals; Input/Output Signal Types And Processing - Mitsubishi Electric MELDAS 60 Series Programming Manual

3. Input/Output Signals

3.1 Input/Output Signal Types and Processing

The input/output signals handled in user PLC are as follows:
(1) Input/output from/to controller
(2) Input/output from/to operation board (Note 1)
(3) Input/output from/to machine
The user PLC does not directly input or output these signals from or to hardware or controller; it inputs
or outputs the signals from or to input/output image memory. For the reading and writing with the
hardware or controller, the controller will perform the input/output according to the level of the main
process or high-speed process.
Controller
Operation
board
Machine
(Note 1) The operation board here refers to when the remote I/O unit is installed on the communication
terminal.
H igh-speed processing
input/output
The c ontr oller reads the
high-speed input
designation input, and
sets in the im age m em ory.
P251
U ser PLC high -speed
proces sin g
The controller outputs
the high-speed output
designation output from
the im age m em or y to the
m achine.
Fig. 3.1-2 Input/output processing conforming to program level
Controller
Fig. 3.1-1 Concept of input/output processing
Input/output image
memory
(device X, Y)
M ain processing
input/output
The c ontr oller reads the
input other than the high-speed
input designation,
and s ets in th e im age m em or y.
P252
U ser PL C m ain
proces sin g
The controller outputs
the output other than the
high-speed output
designation from the
im age m em or y to th e m achine.
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3. Input/Output Signals
User PLC