This article is about an analog electrical signaling scheme. For digital serial communications, see Digital current loop interface. For the oceanic phenomenon, see Loop Current. For the network analysis variable, see loop current.
In electrical signalling an analog current loop is used where a device must be monitored or controlled remotely over a pair of conductors. Only one current level can be present at any time.
A major application of current loops is the industry de facto standard 4–20 mA current loop for process control applications, where they are extensively used to carry signals from process instrumentation to proportional–integral–derivative (PID) controllers, supervisory control and data acquisition (SCADA) systems, and programmable logic controllers (PLCs). They are also used to transmit controller outputs to the modulating field devices such as control valves. These loops have the advantages of simplicity and noise immunity, and have a large international user and equipment supplier base. Some 4–20 mA field devices can be powered by the current loop itself, removing the need for separate power supplies, and the "smart" Highway Addressable Remote Transducer (HART) Protocol uses the loop for communications between field devices and controllers. Various automation protocols may replace analog current loops, but 4–20 mA is still a principal industrial standard.
signalling an analog currentloop is used where a device must be monitored or controlled remotely over a pair of conductors. Only one current level can be present...
A parent to the Florida Current, the LoopCurrent is a warm ocean current that flows northward between Cuba and the Yucatán Peninsula, moves north into...
serial communications, a currentloop is a communication interface that uses current instead of voltage for signaling. Currentloops can be used over moderately...
other. A more general technique, called loop analysis (with the corresponding network variables called loopcurrents) can be applied to any circuit, planar...
In computer science a for-loop or for loop is a control flow statement for specifying iteration. Specifically, a for loop functions by running a section...
magnetic dipole is properly modeled as a currentloop having a current I and an area a. Such a currentloop has a magnetic moment of m = I a , {\displaystyle...
a currentloop, this definition leads to the magnitude of the magnetic dipole moment equaling the product of the current times the area of the loop. Further...
electromagnetism, a magnetic dipole is the limit of either a closed loop of electric current or a pair of poles as the size of the source is reduced to zero...
terminate the currentloop immediately, and transfer control to the statement immediately after that loop. Another term for early-exit loops is loop-and-a-half...
feedback loops: current control loop, velocity control loop and position control loop. The last is the main loop. The other two are minor loops. The forward...
closed circulation of an electric current system. A simple example is a single loop of wire with constant current through it. A bar magnet is an example...
7th Time Loop: The Villainess Enjoys a Carefree Life Married to Her Worst Enemy! (Japanese: ループ7回目の悪役令嬢は、元敵国で自由気ままな花嫁生活を満喫する, Hepburn: Loop 7-kaime no...
constant current source helps for proper signal conditioning with nearly zero reflection from load. Constant currentCurrent limiting CurrentloopCurrent mirror...
make up the material. Both of these are modeled quite well as tiny loops of current called magnetic dipoles that produce their own magnetic field and are...
A loop antenna is a radio antenna consisting of a loop or coil of wire, tubing, or other electrical conductor, that for transmitting is usually fed by...
of the currentloop formed by the conducting rails. In addition, railguns usually require the use of sliding contacts to pass a large current through...
that it can communicate over legacy 4–20 mA analog instrumentation currentloops, sharing the pair of wires used by the analog-only host systems. HART...
inductive loop is an electromagnetic communication or detection system which uses a moving magnet or an alternating current to induce an electric current in...
magnetic moment of a currentloop is defined as m = I A n ^ {\displaystyle \mathbf {m} =IA\mathbf {\hat {n}} } , so if the loop lies in the x-y plane...
An electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net...
themselves are the VT1XX-AB (Advanced Video Option) and the VT1XX-AA (20 mA CurrentLoop Option). The cards' capabilities and existence are described in Chapter...
moment of a currentloop is equal to the current times the area of the loop. Suppose the field is aligned with the z axis. The average loop area can be...
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