eBook: Automating Manufacturing Systems; with PLCs


A.2 B

B-spline - a fitted curve/surface that is commonly used in CAD and graphic systems.
backbone - a central network line that ties together distributed networks.
background - in multitasking systems, processes may be running in the background while the user is working in the foreground, giving the user the impression that they are the only user of the machine (except when the background job is computationally intensive).
background suppression - the ability of a sensing system to discriminate between the signal of interest, and background noise or signals.
backplane - a circuit board located at the back of a circuit board cabinet. The backplane has connectors that boards are plugged into as they are added.
backup - a redundant system to replace a system that has failed.
backward chaining - an expert system looks at the results and looks at the rules to see logically how to get there.
band pressure Level - when measuring the spectrum of a sound, it is generally done by looking at frequencies in a certain bandwidth. This bandwidth will have a certain pressure value that is an aggregate for whatever frequencies are in the bandwidth.
base - 1. a substance that will have an excess of HO ions in solution form. This will react with an acid. 2. the base numbering system used. For example base 10 is decimal, base 2 is binary
baseband - a network strategy in which there is a single carrier frequency, that all connected machines must watch continually, and participate in each transaction.
BASIC (Beginner's All-purpose Symbolic Instruction Code) - a computer language designed to allow easy use of the computer.
batch processing - an outdated method involving running only one program on a computer at once, sequentially. The only practical use is for very intensive jobs on a supercomputer.
battery backup - a battery based power supply that keeps a computer (or only memory) on when the master power is off.
BAUD - The maximum number of bits that may be transmitted through a serial line in one second. This also includes some overhead bits.
baudot code - an old code similar to ASCII for teleprinter machines.
BCC (Block Check Character) - a character that can check the validity of the data in a block.
BCD (Binary Coded Decimal) - numerical digits (0 to 9) are encoded using 4 bits. This allows two numerical digits to each byte.
beam - a wave of energy waves such as light or sound. A beam implies that it is not radiating in all directions, and covers an arc or cone of a few degrees.
bearing - a mechanical support between two moving surfaces. Common types are ball bearings (light weight) and roller bearings (heavy weight), journal bearings (rotating shafts).
beats - if two different sound frequencies are mixed, they will generate other frequencies. if a 1000Hz and 1001Hz sound are heard, a 1Hz (=1000-1001) sound will be perceived.
benchmark - a figure to compare with. If talking about computers, these are often some numbers that can be use to do relative rankings of speeds, etc. If talking about design, we can benchmark our products against our competitors to determine our weaknesses.
Bernoulli's principle - a higher fluid flow rate will result in a lower pressure.
beta ratio - a ratio of pipe diameter to orifice diameter.
beta rays - electrons are emitted from a fission or fusion reaction.
beta site - a software tester who is actually using the software for practical applications, while looking for bugs. After this stage, software will be released commercially.
big-endian - a strategy for storing or transmitting the most significant byte first.
BIOS (Basic Input Output System) - a set of basic system calls for accessing hardware, or software services in a computer. This is typically a level lower than the operating system.
binary - a base 2 numbering system with the digits 0 and 1.
bit - a single binary digit. Typically the symbols 0 and 1 are used to represent the bit value.
bit/nibble/byte/word - binary numbers use a 2 value number system (as opposed to the decimal 0-9, binary uses 0-1). A bit refers to a single binary digit, and as we add digits we get larger numbers. A bit is 1 digit, a nibble is 4 digits, a byte is 8 digits, and a word is 16 digits.

BITNET (Because It's Time NET) - An academic network that has been merged with CSNET.
blackboard - a computer architecture when different computers share a common memory area (each has its own private area) for sharing/passing information.
block - a group of bytes or words.
block diagrams - a special diagram for illustrating a control system design.
binary - specifies a number system that has 2 digits, or two states.
binary number - a collection of binary values that allows numbers to be constructed. A binary number is base 2, whereas normal numbering systems are base 10.
blast furnace - a furnace that generates high temperatures by blowing air into the combustion.
bleed nozzle - a valve or nozzle for releasing pressure from a system.
block diagram - a symbolic diagram that illustrates a system layout and connection. This can be used for analysis, planning and/or programming.
BOC (Bell Operating Company) - there are a total of 7 regional telephone companies in the U.S.A.
boiler - a device that will boil water into steam by burning fuel.
BOM (Bills Of Materials) - list of materials needed in the production of parts, assemblies, etc. These lists are used to ensure all required materials are available before starting an operation.
Boolean - a system of numbers based on logic, instead of real numbers. There are many similarities to normal mathematics and algebra, but a separate set of operators, axioms, etc. are used.
bottom-up design - the opposite of top-down design. In this methodology the most simple/basic functions are designed first. These simple elements are then combined into more complex elements. This continues until all of the hierarchical design elements are complete.
bounce - switch contacts may not make absolute contact when switching. They make and break contact a few times as they are coming into contact.
Bourdon tube - a pressure tube that converts pressure to displacement.
BPS (Bits Per Second) - the total number of bits that can be passed between a sender and listener in one second. This is also known as the BAUD rate.
branch - a command in a program that can cause it to start running elsewhere.
bread board - a term used to describe a temporary electronic mounting board. This is used to prototype a circuit before doing final construction. The main purpose is to verify the basic design.
breadth first search - an AI search technique that examines all possible decisions before making the next move.
breakaway torque - the start-up torque. The value is typically high, and is a function of friction, inertia, deflection, etc.
breakdown torque - the maximum torque that an AC motor can produce at the rated voltage and frequency.
bridge - 1. an arrangement of (typically 4) balanced resistors used for measurement. 2. A network device that connects two different networks, and sorts out packets to pass across.
broadband networks - multiple frequencies are used with multiplexing to increase the transmission rates in networks.
broad-band noise - the noise spectrum for a particular noise source is spread over a large range of frequencies.
broadcast - a network term that describes a general broadcast that should be delivered to all clients on a network. For example this is how Ethernet sends all of its packets.
brush - a sliding electrical conductor that conducts power to/from a rotor.
BSC (Binary Synchronous Communication) - a byte oriented synchronous communication protocol developed by IBM.
BSD (Berkeley Software Distribution) - one of the major versions of UNIX.
buffer - a temporary area in which data is stored on its way from one place to another. Used for communication bottlenecks and asynchronous connections.
bugs - hardware or software problems that prevent desired components operation.
bumpless transfer - a smooth transition between manual and automatic modes.
burn-in - a high temperature pre-operation to expose system problems.
burner - a term often used for a device that programs EPROMs, PALs, etc. or a bad cook.
bus - a computer has buses (collections of conductors) to move data, addresses, and control signals between components. For example to get a memory value, the address value provided the binary memory address, the control bus instructs all the devices to read/write, and to examine the address. If the address is valid for one part of the computer, it will put a value on the data bus that the CPU can then read.
byte - an 8 bit binary number. The most common unit for modern computers.

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