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3-1 Design Precautions
Observe the following precautions when designing a system incorporating a
CPM1A PLC.
3-1-1 Power Supply Wiring
Separate the power supply wiring from the control system, CPM1A system, and
DC I/O system wiring. Separate the control circuits that supply power to the main
Unit from the main circuits using dedicated circuit protectors and fuses.
3-1-2 Interlock and Limit Circuits
Construct an external interlock circuit if CPM1A outputs are used to perform re-
ciprocal operations such as controlling the forward and reverse operation of a
motor or if incorrect PLC operation could cause accidents or mechanical dam-
age. Also, construct an external limit circuit to prevent run-away movement in
systems such as position control.
The following diagram shows an example of an interlock circuit.
Interlock Circuit
Motor forward
Motor reverse
MC1
01005 MC2
MC2
01006 MC1
CPM1A
In the interlock circuit above, MC1 and MC2 can’t be ON at the same time even if
CPM1A outputs 01005 and 01006 are both ON (an incorrect PLC operation).
3-1-3 Power Supply Voltage
Caution
Use the power supply voltages indicated in
Section NO TAG Unit Specifications
and Components
. Failure to adhere to the specifications may result in fire. In
places where power supply conditions are poor, take steps to ensure that power
is supplied at the rated voltage. Be sure to adhere to safety precautions, such as
providing breakers to prevent short circuits in external wiring. When conducting
any of the following operations, turn OFF the power to the PLC. Electrocution,
product damage and malfunction may result.
·
Connecting or disconnecting Expansion I/O Modules and CPU Units.
·
Assembling Units
·
Connecting cables and wiring.
3-1-4 CPM1A Power Interruptions
Supply Voltage Drop
When the supply voltage falls below 85% of the rated value, the PLC will stop
and the outputs will go OFF.
Momentary Power Failure Detection
A momentary power failure lasting less than 10 ms with an AC power supply and
2 ms with a DC power supply is not detected and the CPU Unit continues to oper-
ate.
A momentary power failure lasting longer than 10 ms with an AC power supply
and 2 ms with a DC power supply may or may not be detected in an uncertain
area.
When a momentary power failure is detected, the CPU Unit stops operating and
the output goes OFF.
Design Precautions
Section 3-1
Summary of Contents for CPM1A-20CAR-A
Page 3: ...ii...
Page 5: ...iv...
Page 9: ...iv...
Page 29: ...14 System Configuration Section 1 2...
Page 43: ...29 Unit Components Section 2 2...
Page 65: ...51 Wiring and Connections Section 3 4...
Page 123: ...Appendix B Dimensions 2 CPM1 CIF01 90 81 21 30 205 50 56 CPM1 CIF11 90 81 21 30 205 50 61...
Page 124: ...Appendix B Dimensions 3 Dimensions with Peripheral Devices Attached Approx 90 Approx 125...
Page 125: ...Appendix B Dimensions 4...