What is optocoupler?

Difference between optocoupler and normal diode?

Purpose: An optocoupler (or optical isolator) uses optics to isolate one circuit from another. The diode in the optical isolator is similar to an LED. The light from this LED controls the gate or base of a transistor. A diode has two terminals, an optocouple will have at least 4. A diode is used to control current flow direction; an optocoupler main purpose is to isolate one circuit from another. etc. etc.

What engineering words start with O?

octopus engineering o-ring orbital orthogonal ohms odammit overclocking optocoupler oxide

What is MCT2E optocoupler?

The MCT2E opto coupler is basically a communication protection scheme. The opto coupler provides the galvanic isolation between the sending and the receiving side.

How can i make my own Midi cable need midi cable wiring diagram?

Look here: http://www.philrees.co.uk/midiplug.htm and, in addition: /\ /\ /\ / ################# \ /\ 1 -|- | | ################# | | ----- 1 | | | ################# | | | 2 -|-----/ ################# \--|------ 2 | | ################# | | 3 -|- | ################# | ----- 3 | | ################# | | 4 -|----------#################---|------ 4 | | ################# | | 5 -|----------#################---|----- 5 | | ################# | | \/ ################# \/ \_ SHIELD _/ Metal shell of DIN Connector MIDI IN : 1- n.c. 4- anode of optocoupler 2- n.c. <<<--- !!!! Different for MIDI OUT 5- cathode of optocoupler 3- n.c. MIDI OUT/THRU: 1- n.c. 4- +5v thru resistor 2- local ground 5- TTL open collector ouput 3- n.c.

What is the purpose of an optocoupler?

The main purpose of an Opto-isolator is "to prevent high voltages or rapidly changing voltages on one side of the circuit from damaging components or distorting transmissions on the other side.

What is the function of optocoupler?

An optocoupler provides galvanic isolation between the sending and the receiving side of an information stream. The signal crosses the galvanic isolation by being transmitted by a light emitting diode (or a similar mechanism), and is received by a light-sensitive device such as a photo diode or resistor. Common uses of opto couplers include the trigger system of triacs and thyristors, electronic devices dealing with high voltage and current. In those systems, the opto coupler protects the sensitive control logic and equipment that manages the trigger signals from the high power load path. Other common uses of opto couplers are in computing, where devices need connecting to enable exchange of data and where galvanic isolation is desired to keep both sides decoupled. Fibre optic data cables are also very similar to an opto coupler. A typical opto coupler has a thin galvanic isolation barrier (a think layer of glass or similar plastic material) between the light transmitting and light receiving sides. A fibre optics "cable" works much in the same way, except the isolating (but light-conducting) barrier is a very long fibre of glass (or a similar material).

How can you use an analog telephone signal to activate a digital relay?

There are many different ways this could be done depending on the purpose and exactly which analog telephone signal is to be used.ring signal, this is a 120VAC 5Hz pulsed signal present between tip & ring when the phone is on hook and being called; a high voltage insulated optocoupler must be used to trigger a oneshot or flipflop that will control a relay driver to operate the relayon/off hook switching, when on hook 48VDC is present between tip & ring, when off hook this voltage drops below about 10VDC; these states are probably best sensed using a level detector on a floating power supply (to protect against damage by the ring signal) and a high voltage insulated optocoupler must be used to control a relay driver to operate the relayAF tone signal, this is a signal somewhere between 50Hz and 3KHz; a 600 ohm to 600 ohm transformer should be used to block the ring signal and DC on/off hook voltages, this transformer should drive an amplifier (and maybe a clipper) the output of which goes to one or more phase locked loops set to specific frequencies, the phase locked loop outputs each control separate relay drivers to operate the relaysNote: these are not the only way to accomplish this, in fact commercial off the shelf phone interface modules are available that will handle the ring and hook signals for you (maybe even including the relay drivers or even actual relays) and provide the AF signal ready to feed to the phase locked loops. Such modules may actually be the best way to start if you don't want to run the risk of a mistake that might cause the phone company to disconnect service for a detected fault that could damage their equipment.

Basics of programmable logic controllers?

PLCs were invented in the 60/70's for the automotive manufacturing industry. Since this time, they have developed into one of the most versatile tools used for industrial automation. A working knowledge of PLCs and other microprocessor based control systems are critical to technical personnel who are staying current with technology in industry. Programmable Logic Controllersor PLC are the hub of many manufacturing processes. These microprocessor based units are used in processes as simple as boxing machines or bagging equipment to controlling and tracking sophisticated manufacturing processes. They are in virtually all new manufacturing, processing and packing equipment in one form or another. Because of their popularity in industry, it becomes increasingly more important to learn skills related to these devices. Click on the buttons to learn more about industrial automation and this invaluable tool. The microprocessor or processor module is the brain of a PLC system. It consists of the microprocessor, memoryintegrated circuits, and circuits necessary to store and retrieve information from memory. It also includes communications ports to other peripherals, other PLC's or programming terminals. Today's processors vary widely in their capabilities to control real world devices. Some control as few as 6 inputs and outputs (I/O) and others 40,000 or more. One processor can control more than one process or manufacturing line. Processors are often linked together in order to provided continuity throughout the process. The number of inputs and outputs PLCs can control are limited by the overall capacity of the PLC system hardware and memory capabilities. The job of the processor is to monitor status or state of input devices, scan and solve the logic of a user program, and control on or off state of output devices.RAM or Random Access Memory is a volatile memory that would lose it's information if power were removed..This is why some processor units incorporate a battery back up. The type of RAM normally used is CMOS orComplementary Metal Oxide Semiconductor. CMOS RAM is used for storage of the user's program (ladder logic diagrams) and storage memory.ROM or Read Only Memory is a non-volatile type of memory. This means you don't need an external power source to keep information. In this type of memory, information can be read, but not changed. For this reason the manufacture sometimes calls this firmware. It is placed there for the internal use and operation of processor units EEPROM or Electrically Erasable Programmable Read Only Memory is usually an add-on memory module that is used to back up the main program in CMOS RAM of the processor. In many cases, the processor can be programmed to load the EEPOM's program to RAM if RAM is lost or corrupted.Input ModuleThere are many types of input modules to choose from. The type of input module used is dependent upon what real world input to the PLC is desired. Some examples of inputs are limit switches, electric eyes, and pushbuttons. DC inputs, such as thumbwheel switches, can be used to enter integer values to be manipulated by the PLC. DC input cards are used for this application. Since most industrial power systems are inherently noisy, electrical isolation is provided between the input and the processor. Electromagnetic interference (EMI) and Radio Frequency Interference (RFI) can cause severe problems in most solid state control systems. The component used most often to provide electrical isolation within I/O cards is called an optical isolator or optocoupler. The wiring of an input is not complex. The object is to get a voltage at a particular point on the card. Typically there are 8 to 32 input points on any one input module. Each point will be assigned a unique address by the processor. Analog input modules are special input cards that use analog to digital conversion (A to D) to sense variables such as temperature, speed, pressure, and position. The external device normally is connected to a controller (transducer) producing an electrical signal the analog input card can interpret. This signal is usually 4 to 20 Ma or a 0 to 10 volt signal.Output ModuleOutput modules can be for used for ac or dc devices such as solenoids, relays, contractors, pilot lamps, and LED readouts. Output cards usually have from 6 to 32 output points on a single module. The output device within the card provides theconnection from the user power supply to the load. Usually silicon controlled rectifiers (SCR), triac, or dry contact relays are use for this purpose. Individual outputs are rated most often at 2 to 3 amperes. Output cards, like input cards have electricalisolation between the load being connected and the PLC. Analog output cards are a special type of output modules that use digital to analog conversion (D to A). The analog output module can take a value stored in a 12 bit file and convert it to an analog signal. Normally this signal is 0 -10 volts dc or 4 to 20 Ma. This analog signal is often used in equipment such as motor operated valves and pneumatic position control devices PLC programs are made up of a combination of the above "gates" together with inputs, outputs, timers, counters, internal memory bits, analog inputs, analog outputs, mathematical calculations, comparators etc. We will now look closer at some of these and the operation of the PLC. INPUTS These are the physical connections from the real world to the PLC. They can be limit switches, push buttons, and sensors, anything that can "switch" a signal on or off. The voltage of these devices are usually, but not always, 24 Volt DC. Manufacturers make inputs that can accept a wide range of voltages both ac and dc. It should be remembered that an input will be ON, "status 1", when the voltage is present at the input connection and OFF, "status 0", when the voltage is no longer present at the input connection. OUTPUTS These are the connections from the PLC to the real world. They are used to switch solenoids, lamps, contactors etc on and off. Again they are usually 24 Volt DC, either relay or transistor, but can also be 115/220 Volt ACINTERNAL MEMORY BITS (RELAYS)These so called relays only exist in the PLCs memory, they are used to remember certain "states" or functions that have been performed. They react exactly like ordinary relays and can be on, off or latching. Manufacturers of PLCs also pre-program certain internal relays with special functions such as, always on; always off; on whilst the PLC is powering up; on for the first scan of the program; on if there is an error. For details of other pre-programmed relays you will have to check the manual for the PLC you are going to use. THE PLC Now that we have a basic understanding of the workings of a PLC and some of the numbering systems used we can look at the operation of PLCs.A PLC operates by continually scanning the program and acting upon the instructions, one at a time, to switch on or off the various outputs. In order to do this the PLC first "looks" at all the inputs and remembers their states ( i.e.. "1" or "0" / on or off) this information is then stored in memory. The PLC then scans the program instructions and decides if an output should be on or off BUT, and this is important to remember, the physical output is NOT turned on immediately. When the PLC has finished scanning the programmed instructions it will, finally, turn on the required outputs. This is called updating the process output image.At this point the PLC then checks its own operating system and if everything is ok it then goes and checks the states of the inputs and starts all over again.This is program scanning and the delay is called the program scan time.From the above statement it should be seen that there is a delay from when an input is turned on; the program scanned and then a physical output being turned on or off. As the delay is only mS it is not usually a problem unless you are using the PLC in a high speed process. However it should be remembered that in a PLC with many thousand I/O an input could turn on and then off before the PLC has finished scanning the programmed instructions.This could result in an output coming on for one or two scans when in fact it should be off. COMMUNICATIONSThere are several methods to communicate between a PLC and a programmer or even between two PLCs.Communications between a PLC and a programmer (PC or Hand held) are provided by the makers and you only have to plug in a cable from your PC to the programming port on the PLC. This communication can be RS232; RS485 or TTY.Communications between two PLCs can be carried out by dedicated links supplied/programmed by the makers (RS232 etc) or via outputs from one PLC to the inputs on another PLC.This direct link method of communication can be as simple as, if an output on the first PLC is on then the corresponding input on the second PLC will be on and then this input is used within the program on the second PLC.If a word of input/outputs (16 bits) are used then numerical data can be transferred from one PLC to the other (refer back to the section on numbering systems).There are many other methods of communication between PLCs and also from PLC to PC. Please refer to the manuals supplied with the PLC that you are using for full details on communications

What is optocoupler?

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Basics of programmable logic controllers?