2-Chennel Relay Module User Guide

2-Chennel Relay Module User Guide
Handson Technology
User Guide
2 Channel 5V Optical Isolated Relay Module
This is a LOW Level 5V 2-channel relay interface board, and each channel needs a 15-20mA
driver current. It can be used to control various appliances and equipment with large current.
It is equipped with high-current relays that work under AC250V 10A or DC30V 10A. It has
a standard interface that can be controlled directly by microcontroller. This module is
optically isolated from high voltage side for safety requirement and also prevent ground loop
when interface to microcontroller.
Brief Data:
Relay Maximum output: DC 30V/10A, AC 250V/10A.
2 Channel Relay Module with Opto-coupler. LOW Level Trigger expansion board, which is
compatible with Arduino control board.
Standard interface that can be controlled directly by microcontroller ( 8051, AVR, *PIC, DSP,
ARM, ARM, MSP430, TTL logic).
Relay of high quality low noise relays SPDT. A common terminal, a normally open, one
normally closed terminal.
Opto-Coupler isolation, for high voltage safety and prevent ground loop with microcontroller.
VCC and RY-VCC are also the power supply of the relay module. When you need to drive a large power
load, you can take the jumper cap off and connect an extra power to RY-VCC to supply the relay; connect
VCC to 5V of the MCU board to supply input signals.
NOTES: If you want complete optical isolation, connect "Vcc" to Arduino +5 volts but do NOT connect
Arduino Ground. Remove the Vcc to JD-Vcc jumper. Connect a separate +5 supply to "JD-Vcc" and board
Gnd. This will supply power to the transistor drivers and relay coils.
If relay isolation is enough for your application, connect Arduino +5 and Gnd, and leave Vcc to JD-Vcc
jumper in place.
It is sometimes possible to use this relay boards with 3.3V signals, if the JD-VCC (Relay Power) is provided
from a +5V supply and the VCC to JD-VCC jumper is removed. That 5V relay supply could be totally
isolated from the 3.3V device, or have a common ground if opto-isolation is not needed. If used with
isolated 3.3V signals, VCC (To the input of the opto-isolator, next to the IN pins) should be connected to the
3.3V device's +3.3V supply.
NOTE: Some Raspberry-Pi users have found that some relays are reliable and others do not actuate
sometimes. It may be necessary to change the value of R1 from 1000 ohms to something like 220 ohms, or
supply +5V to the VCC connection.
NOTE: The digital input s from Arduino are Active LOW: The relay actuates and LED lights when the input
pin is LOW, and turns off on HIGH.
Module Layout:
Operating Principle:
See the picture below: A is an electromagnet, B armature, C spring, D moving contact, and E fixed contacts.
There are two fixed contacts, a normally closed one and a normally open one. When the coil is not energized,
the normally open contact is the one that is off, while the normally closed one is the other that is on.
Supply voltage to the coil and some currents will pass through the coil thus generating the electromagnetic
effect. So the armature overcomes the tension of the spring and is attracted to the core, thus closing the
moving contact of the armature and the normally open (NO) contact or you may say releasing the former
and the normally closed (NC) contact. After the coil is de-energized, the electromagnetic force disappears
and the armature moves back to the original position, releasing the moving contact and normally closed
contact. The closing and releasing of the contacts results in power on and off of the circuit.
VCC : Connected to positive supply voltage (supply power according to relay voltage)
GND : Connected to supply ground.
IN1: Signal triggering terminal 1 of relay module
IN2: Signal triggering terminal 2 of relay module
Each module of the relay has one NC (normally close), one NO (normally open) and one COM (Common)
terminal. So there are 2 NC, 2 NO and 2 COM of the channel relay in total. NC stands for the normal close
port contact and the state without power. NO stands for the normal open port contact and the state with
power. COM means the common port. You can choose NC port or NO port according to whether power or
Testing Setup:
When a low level is supplied to signal terminal of the 2-channel relay, the LED at the output terminal will
light up. Otherwise, it will turn off. If a periodic high and low level is supplied to the signal terminal, you
can see the LED will cycle between on and off.
For Arduino:
Step 1:
Connect the signal terminal IN1、IN2 of 2-channel relay to digital pin 4 & 5 of the Arduino Uno or
ATMega2560 board, and connect an LED at the output terminal.
IN1> 4
IN2> 5
Step 2:
Upload the sketch "text_code" to the Arduino Uno or ATMega2560 board.Then you can see the LED cycle
between on and off.
The actual figure is shown below:
For raspberry Pi:
Connect the signal terminal IN2、IN1 of 2-channel relay to port 17、18 of the Raspberry Pi, and connect an
LED at the output terminal.
IN2 > 17
IN1 > 18
Step 2:
Run the “test_code”. Then you can see the LED cycle between on and off.
Sketch for Arduino:
Description: control the 2 channel relay module to ON or OFF
Website: www.handsontec.com
Email: techsupport@handsontec.com
//the relays connect to
int IN1 = 4;
int IN2 = 5;
#define ON
#define OFF
void setup()
relay_init();//initialize the relay
void loop() {
relay_SetStatus(ON, OFF);//turn on RELAY_1
delay(2000);//delay 2s
relay_SetStatus(OFF, ON);//turn on RELAY_2
delay(2000);//delay 2s
void relay_init(void)//initialize the relay
//set all the relays OUTPUT
pinMode(IN1, OUTPUT);
pinMode(IN2, OUTPUT);
relay_SetStatus(OFF, OFF); //turn off all the relay
//set the status of relays
void relay_SetStatus( unsigned char status_1, unsigned char status_2)
digitalWrite(IN1, status_1);
digitalWrite(IN2, status_2);
Code for Raspberry Pi:
#!/usr/bin/env python
* Filename
: 2_channel_relay.py
* Description
: a sample script for 2-Channel High trigger Relay
* E-mail
: techsupport@handsontec.com
* Website
: www.handsontec.com
* Detail
: New file
import RPi.GPIO as GPIO
from time import sleep
Relay_channel = [17, 18]
def setup():
GPIO.setup(Relay_channel, GPIO.OUT, initial=GPIO.LOW)
print "|=====================================================|"
print "|
2-Channel High trigger Relay Sample
print "|-----------------------------------------------------|"
print "|
print "|
Turn 2 channels on off in orders
print "|
print "|
17 ===> IN2
print "|
18 ===> IN1
print "|
print "|
print "|=====================================================|"
def main():
while True:
for i in range(0, len(Relay_channel)):
print '...Relay channel %d on' % i+1
GPIO.output(Relay_channel[i], GPIO.HIGH)
print '...Relay channel %d off' % i+1
GPIO.output(Relay_channel[i], GPIO.LOW)
def destroy():
GPIO.output(Relay_channel, GPIO.LOW)
if __name__ == '__main__':
except KeyboardInterrupt:
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