Просмотр кода страницы Управление низковольтной нагрузкой/en

<languages/>
There are the so-called "transistor outputs", also FET, to control the low-voltage load (with voltage up to the input voltage) in the Wiren Board controllers. They can control the switching of low-voltage lamps, led strips, external relay blocks, etc.

All transistor outputs can be controlled from the [[Веб-интерфейс Wiren Board/en |  
 web interface]], where they are called according to the terminals, for example A1_OUT.


==Technical detail==

[[File:Ax.png|thumb|400px|Equivalent Ax output circuit for WB4 controller]]
To reduce the total number of terminals, the low-voltage load control channels are combined with ADC channels - see[[Мультиплексирование портов/en |Multiplexing ports]]. Therefore, the outputs have a large, but the final resistance (30-100k). This can cause, for example, a weak glow of led strips ''(The solution is: add a resistor to the power supply)''.

'''Note for Wiren Board versions 2.8 and 3.5:'''
* when connecting inductive loads (relay) do not forget to put a protective diode - a surge of voltage from the relay coil can damage the controller. Maximum current per channel - 3A, voltage up to 24V.
'''Note for Wiren Board version 4:'''
A protective diode is built-in in Wiren Board 4 controller and the maximum voltage must not exceed the controller supply voltage (Vin). The maximum current is also 3 A. If multiple channels are used and '''the total current is greater than 5 A, connect multiple GND terminals to the "minus" of the power supply.'''


==The examples of use==

[[File:Led.png|thumb|400px|Led connection example]]
[[File:Relay.png|thumb|400px|Relay connection example]]

The load is connected as follows: "plus" load is connected to the power supply, "minus" is connected to the transistor output. For the load to start working, you need to apply a high level to the gate of the transistor. 

The illustrations show the wiring diagrams of the led and relay.

You can also easily connect a ready relay module, [http://dx.com/p/4-channel-5v-relay-module-black-blue-171144 such as]


==The example of work in Linux==

See [[GPIO/en|GPIO]].

# Find the GPIO number corresponding to the desired terminal in the table[[Список GPIO/en|WB2.8]]/[[WB SH 3.5: Список GPIO/en|WB3.5]]/[[Wiren Board 4: Список GPIO/en|WB4]]/[[Wiren Board 5:Список GPIO|WB5]]. For terminal strip number 2 in version 2.8, it is GPIO 32.
# Export GPIO to sysfs
#:<pre>root@wirenboard:~# echo 32 > /sys/class/gpio/export</pre>
# Set the GPIO to output mode to control the transistor. This is required because GPIO can be in input mode and have a high impedance, leaving the transistor in an undefined state.
#:<pre>root@wirenboard:~# echo out > /sys/class/gpio/gpio32/direction</pre>
# Open the transistor, giving a logical high level to the gate:
#:<pre>root@wirenboard:~# echo 1 > /sys/class/gpio/gpio32/value</pre>
# Close the transistor, giving a logical zero to the gate:
#:<pre>root@wirenboard:~# echo 0 > /sys/class/gpio/gpio32/value</pre>