Editing Smart Box Relays

The Smart Box Relays can be used to control electrical devices from the digital outputs on Smart Box.
These devices will typically require larger voltages or currents than available direct from the digital output.
The relays can switch a maximum of 3 Amps at 40 volts.
Two versions are available, one contains a single pole changeover relay and the other a double pole changeover relay.
The units are protected internally by a fuse which can be replaced if required by unscrewing the lid of the case.
Fuses must be replaced with a fuse of the same type and rating.

The Smart Box Relay should be connected to one of the digital outputs on Smart Box. When the digital output is ‘off’ current will be able to flow through the common (COM.) and normally closed (N.C.) connections.
When the digital output is switched ‘on’ the LEDs on the relay unit will light and a circuit will be made between the common and normally open (N.O.) connections.

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'''''Warning'''''
''The POWER, SPEED and PULSE commands should not be used with the relay as the rapid switching can cause mechanical failure of the unit.''
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Fig. 1 shows a typical circuit in which the single pole relay is being used to switch a device on and off.
Power from an external supply is connected to the Common connection on the unit.
The device, in this case a 12 Volt bulb, is connected between the Normally Open socket on the Smart Box Relay and the 0 Volt connection on the power supply.

Fig. 2 shows how two Smart Box Relays can be used to control a motor with on/ off and forward/ backward control.
A single pole relay is used to switch the power from the external supply on and off.
A double pole relay controls the polarity of the supply to the motor.
Connections are made between the N.O. and N.C connections on each pole of the relay.
Stacking 4mm plugs should be used to make these connections.
In this example switching output 0 off and on will stop and start the motor while output 1 will control the direction of rotation of the motor.

[[Category:Outputs]]
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