Opto coupler vs solid state relay for low voltage application. I have use dual opto couplers to only switch on a circuit of the. In fact we can even change the polarity of the higher voltage supplies without regard to the digital circuit common negative grounds if needed. Relay driver circuit using ic uln2003 with applications. We can use seven relays with relay driver circuit using uln2003 and the relay driver circuit using uln2803 enables to. Opto modules and solid state relays product information 2. The following post describes how to drive a relay by using an isolated method, or through an optocoupler device. Latchingnonlatching relay driver circuit with darlington optocoupler. Linear opto isolator circuits elec circuit electronic. Overview the usboptorly816 provides eight optically isolated inputs and eight volt free contact relay outputs with a current rating of up to 16amp each. Circuit description the starter solenoid lockout relay driver circuit is a solenoid driven by the ecm, which isolates the starter motor relay, electrically, when the engine is running. I figured that the logic gets inverted when i used the gpio as the source voltage for the optoisolator led. With r1 and r2 at those values, the opto transistor will always be switched on.
I am guessing that you have a 50v supply with a morse key driving a relay. Once you replace the relay and opto isolator you are back in business. Driving relay directly from optocoupler, what is best. Whether relay sockets or pluggable relay and optocoupler modules, wagos array of relays and optocouplers offer a solution for any requirement. Even without the transistor it would be nearly safe connect arduino pin to 12v via 10k resistor but not driving the relay ofc. If the coil shorts the opto transistor will almost always burn out. An optoisolator also called an optocoupler, photocoupler, or optical isolator is an electronic component that transfers electrical signals between two isolated circuits by using light. The schematic of the switch is shown in the image above. How to make an 8 channel relay driver board optically isolated. Otherwise i dont think much harm can cross the 10k resistor and transistor. As you probably know is the the simple opto coupler consists of irinfared diode and a photo transistor. How to connect a relay through an optocoupler homemade. Circuit options explore issues, solutions for relay drivers.
As shown in the following circuit diagram, the relay driver may consist a npn transistor or a pnp transistor. Why are relays so frequently driven by optocouplers. Fault code 474 starter solenoid lockout relay driver circuit. Top 5 elctronic project with bc547 transistor, tri ac, rgb led, photo diode duration. What is the difference between a relay and an optocoupler. How to use optocoupler and triac to control ac load. Phoenix contact optocouplers with solid state relay output. Since there is an insulation layer between the opto led and the opto transistor good for about 4kv nothing will happen to the led or its drive circuit the prop pin or whatever. If you happen to have 48 volt relays, the driver circuit should work fine with a larger value for r2. Optoisolated 2 channel relay board we have sold thousands, now get a good price.
It can be controlled directly by microcontroller raspberry pi, arduino, 8051, avr, pic, dsp, arm, arm, msp430 ttl logic. This interfacing is possible thanks to abbs relays and optocouplers ranges, which offer wide adaptation in both voltage from 5 to 400 v and current from 107 to 16 a as well as high isolation between input and output from 2 to 4 kv. An optocoupled solidstate relay ssr is a device that can be used as a superior replacement for many types of lowpower. A relay driver circuit is a circuit which can drive, or operate, a relay so that it can function appropriately in a circuit. In circuit we use the opto compiler ics number of moc 5010 as a base. Isolated outputs with an isolation voltage range of to 5000v can be provided simply by adding additional optical couplers. I think the ssr is simply taking too much voltagecurrent from the circuit and the relay.
The 8 channel relay module has its own optocoupler also called optoisolator, photocoupler or. An optocoupler is contains a light emitting diode and a light sensitive transistor close together in one package. These simple optocoupler relay driver circuits can be used in variety of electronic projects. The driven relay can then operate as a switch in the circuit which can open or close, according to the needs of the circuit and its operation. So, if the gain of the relay driver is 200 and, the gain of the transistor within the optocoupler is 10, the total gain is now 2,000. Here we have used 12v 10amp relay in this pcb board, but you can also use 5v relays. The circuit allowed the output of a relay driver to connect to a computer even though the relay driver delivered a voltage as high as 24v and the relay driver had no ground connection. The most distinct part of optocoupler as a switch is to isolate low voltage circuit from high voltage circuit. Optocouplers and optoisolators can be used on their own, or to switch a range of other larger electronic devices such as transistors and triacs providing the required electrical isolation between a lower voltage control signal, for example one from an arduino or microcontroller, and a much higher voltage or mains current output signal. Circuit b optocoupler upsets circuit a optocouplers. In a normally closed nc relay switch, when power is supplied to the relay, the load circuit is open and the power source connected to the relay is turned off. I am controlling a relay with stm32 micro controller. Technical data pushbutton limit switch sensor optocoupler relay or optocoupler plc motor contactor motor. This blog is intended to help beginners start with interfacing optocoupler relay boards with microcontrollers.
Optoisolators prevent high voltages from affecting the system receiving the signal. It is so close, in fact, that one can be wired as a runstop latch circuit. In this 4channel relay driver circuit we have used an optocoupler whic his triggered by active low signal, to trigger the npn transistor which further drives the relay. I think it would help if we could see the rest of the driverside of the circuit. Few realize how close an optical coupler resembles a relay. Component location refer to an oem diagram for the exact location. Commercially available optoisolators withstand inputtooutput voltages up to 10 kv and voltage transients. Relay drivers gate drivers are available at mouser electronics. The question was asked by one of the interested members of this blog, miss. Figure 3 schematic diagram of 28 volt coax relay driver figure 4 coax relay driver in altoids tin other relay voltages the driver circuit should also work fine for 12 volt relays, if your rig wont drive a relay directly. In case of an optocoupler connections need some more care. Optoisolated transistor drivers microcontroller interfacing. For example, separate the circuit from the power line, send an audio signal, electronic medical, etc.
The key element of the circuit is an optoisolated solid state relay ssr by sharp. Typical relay current driver circuit use an optocoupler connected to a transistor which then drives the relay. Connecting optocouplers photocouplers to keyboards. The circuit as drawn will not work, i would also advise you, use a transistor driver after the opto. Usboptorly816, 8 optically isolated inputs, 8 16amp relay outputs technical documentation. The circuit shown in figure 1 will drive the relay through optocoupler in same circuit with same power supply. As my relay coil needs around 250 ma, i used a mps222 transistor. Elegoo 8 channel dc 5v relay module with optocoupler. Opto coupler vs solid state relay for low voltage application home. You have not indicated what is the relay coil currentresistance. It is difficult to use a number of relays with transistors, so, relay driver ic uln2003a can be used for availing more relays. I thought id seen one somewhere in cl but i couldnt find it so heres one i made earlier. Cs1107 single relay driver ic this asic provides up to 350 ma of drive current for driving a relay.
Here is a simple microcontrollerrelay interface circuit with perfect galvanic. Relays and optocouplers relay interfaces r600 relay modules rb 1215vdc 10 0,02 rb 12112vdc 10 0,02 rb 12124vdc 10 0,02 rb 121 a24vacdc 10 0,02. With optoisolators we can sever this connection including the use of highervoltage power supplies totally isolated from the lowvoltage digital circuits. They galvanically isolate the low and highvoltage sides of a circuit by using an infrared emitter to transmit the control signal to a photo. But beware, most common optos have a high saturation voltage because of the limited base drive, sometimes in the order of 1 volt. As safety products, optocouplers are designed to protect sensitive control circuitry or people from high voltages. Can omit resistor for about 15 ma into diode vcc 17459 note. The phototransistor can be used to switch current in the output circuit.
You would also need a suppression diode across the relay coil to protect the transistor. It is used to switch high loads or loads that needs ac current to operate. This means that you require much less forward led current from the controller io port pin to turn on the relay. Examplein terms of usage say a person wants to turn on 500 kw motor, he could simply. Use them in any sector of industry including process technology and power engineering, railway applications and machine engineering, as well as general control cabinet construction. Opto 22 240d25 dc control solid state relay, 240 vac, 25 amp, 4000 v optical isolation, 12 cycle maximum turnonoff time, 25 65 hz operating frequency. Both the diode and the transistor have specifications.
For demonstrating the working of this relay module, we have used. The wellestablished relaydriving circuit uses an optocoupler to isolate the grounds and noise coupling between the lowvoltage digitalcontrol signal circuit. Opto 22 240d25 dc control solid state relay, 240 vac, 25. These din rail mount optocouplers from phoenix contact provide an ideal means of interfacing onoff signals to, or from, equipment, whilst providing electrical isolation between their own inputs and outputs. Its advantage is completly isolated power you dont have to connect grounds and so less noise will reach rest of your circuit.
When you drive a current i d through the diode, the diodes light will turnon the transistor. Circuit diagram for low voltage relay driver construction and working source power supply connected with relay and max4624 ics power pin 2 and 6, the digital control input pin connected through r1 and c1 components. Onchip diagnostic features include open and short circuit detection in the on state, duty cycle current limit control, and thermal shutdown. Because of the high current gain of the darlington, this coupler has a typical minimum ctr value of about 300%, but has a useful bandwidth of only 30khz. Elegoo stepstick stepper motor driver module a4988. One advantage over the relay is that it may be turned off via a normally open contact. Basic transistor relay driver, actuated on high input npn this circuit will drive a relay coil from a low power output, usually from an ic like 555 or a ttlcmos.
Basically, the gain of the one transistor is multiplied by the gain of the second transistor. Optoisolator coupler circuits, schematics or diagrams by david johnson and others. Optocoupler tutorial about how optocouplers and optoisolators use light to. This is a 5v 4channel relay interface module, for controlling various appliances, and other equipments with large current. Every opto 22 solidstate relay is subjected to full load test and six times the rated current surge both before and after encapsulation. Of course i wouldnt put an opto coupler or a zener in a mass produced. With the values in fig 1 the low and high thresholds at the circuits. This is the linear opto isolator circuits that use a few parts and cheap. I have chosen a part named s216s02 specified for 16 a and 600 v with builtin zerocrossing zc circuit. Microopto solid state relays datasheet 376 kb download. We will describe the hardware interfacing of such relay boards with the popular platform arduino.
1434 1523 1474 19 1281 1078 392 422 1124 1242 732 269 59 750 1402 381 996 201 1317 1212 817 468 1243 993 1303 322 1521 1133 1463 964 1139 876 1213 1403 559 349 784