Yamaha RCX142, User Manual

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Parallel I/O interface
4. Caution items
1. When using a dual-lead proximity sensor as an input signal, check whether
or not it is within input signal specifications.
If the sensor has a high residual voltage during on and off, this might cause
possible malfunctions.
2. Take noise preventive measures when using an inductive load such as a
solenoid valve as an output load. For example, connect a diode (high-speed
type) in parallel at both ends of a load, as a surge killer to protect against
noise.
3. If a short occurs in the load or an excessive current flows, the internal over-
current protective circuit shuts off the interface circuit. Once this protective
circuit is activated, it is not possible to restore the previous state.
Furthermore, heat generated inside might damage the internal circuits, so
always draw current only within the rated load.
4. As a noise prevention, keep the machine power cables separate and make
sure wires are well shielded.
5. Do not keep supplying the external 24V DC power to the standard and
optional I/O interfaces while controller power is off. The controller might
malfunction if the external 24V is continuously supplied.