Binary coded decimal

In addition, most devices provide operator control of settings for temperature and/or response slope, isopotential point, zero or standardization, and function (pH, mV, or monovalent—bivalent cation—anion). Microprocessors are incorporated in advanced-design meters to faciHtate caHbration, calculation of measurement parameters, and automatic temperature compensation. Furthermore, pH meters are provided with output connectors for continuous readout via a strip-chart recorder and often with binary-coded decimal output for computer interconnections or connection to a printer. Although the accuracy of the measurement is not increased by the use of a recorder, the readabiHty of the displayed pH (on analogue models) can be expanded, and recording provides a permanent record and also information on response and equiHbrium times during measurement (5). 

EBCDIC (Extended Binary Coded Decimal Interchange Code)... 

Another commonly employed encoding scheme is that of binary coded decimal bed). In this case each decade of the denary (decimal) number is coded separately into its binary equivalent and each denary digit has a maximum of four bits. The number of bits required in this case to encode a decimal number x is ... 

Mnemonic Sugar Position of hydroxyl groups C4 C3 C2 Binary code Decimal number... 

Results of on-line, real-time instrumental analyses are posted directly to the database, with or without processing, as soon as the instrument presents the analytical data. All results are available for review and validation immediately after being posted -a feature critical to effective laboratory management. Data is acquired from laboratory instrumentation of virtually any manufacturer or function. Instruments are interfaced to the computer via analog to digital conversion, RS-232C, current loop, IEEE-4888, binary coded decimal (BCD) or bit parallel techniques. 

Communication with the auto-sampler via Binary Coded Decimal (BCD) or equivalent communication for sample continuity. This is, in my view, essential, but it is usually ignored by many and offered as an option by many suppliers. 

The second requirement is a coding scheme that allows digital data to represent alphanumeric characters. Several such standards already exist, notably the American Standard Code for Information Interchange (ASCII) and the Extended Binary Coded Decimal Interchange Code. ASCII is almost universally used in microcomputer systems and is probably the better choice for development of new systems. 

There are three methods in common use by which digital data are communicated between devices. In this section we will discuss these methods. They are a) Binary Coded Decimal (BCD), b) RS232, and c) IEEE-488 GPIB. With each of these methods, the sending unit and the receiving unit must have the same type of communication port (Handbooks). 

BCD (Binary Coded Decimal)—Mathematical system using binary (zeros and ones) notation to represent decimal (base 10) numbers. 

Convert each of the decimal numbers in Problem 4-1 into binary-coded-decimal (BCD) numbers. 

Table 23.7. Binary Coded Decimal BCD) Number System... 

Since we are accustomed to thinking in terms of the decimal (base 10) number system, decade counters are often used in interface systems. They not only count in powers of 10 but can be used to divide clock frequencies in decade rather than binary steps. The decade counter presented in Figure 23.20, along with its timing chart, follows the count sequence presented in Table 23.7. The BCD Binary Coded Decimal) number system is a binary representation of the decimal number system. 

The most commonly used ADC output format is the binary number system, because it is directly compatible with many digital computers. Other codes, usually binary coded decimal, are sometimes used. In addition, bipolar input-converters such as the 1 V or 10 V units can have different forms of binary coding to account for the dual polarity. 

Various types of codes have been developed for serving different purposes. There are codes that enable characters in an alphabet to be individually expressed in terms of codes in a smaller alphabet. For example, the alphabet of decimal numeric symbols can be expressed in terms of the binary alphabet by the binary coded decimal (BCD) or 8421 code shown in Table 1.15. The 8421 designation represents the weight given to each of the binary digits in the coding process. 

Binary coded decimal (BCD) Each decimal digit is expressed individuaUy in binary form. 

BCD binary coded decimal binary-coded decimal notation... 

EBCDIC extended binary coded decimal interchange code Eb / No signal energy per bit per hertz of thermal noise... 

The digital display has elements of simplicity and exactness that are not found on a scale and needle readout. The exact pH value is clearly displayed without need of interpretation. The pH value is always in expanded form reading to a hundreth or a thousandth of a pH unit without changing modes. The exact pH value is easily recorded on paper tape by connecting the BCD (binary coded decimal) output from a digital pH meter to a printer. 

The output requirements are totally dependent on the user s needs. If a readout indicator is required, a wide selection is usually offered. An analog output suitable for recording, monitoring and control is commonly provided. In addition, most manufacturers offer a broad selection of output functions, including digital [binary coded decimal (BCD) coded] outputs, high, low, and proportional set points, signal peak or valley sensors, sample and hold circuits, and even closed-loop controls for specific applications. Many presently available instruments, even portable handheld units, include microprocessors that provide many of the above functions on standard models. 

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