 Hello, friends welcome to the new post in this post we will have a detailed look at Introduction of BCD. The binary coded decimal system is type of binary coding used in decimal numbers that every number is denoted through certain values of bits generally 4 or 8. To discuss indications and signs special pattern is used.

In this post, we will discuss the relation and effect of BCD on the PLC working and find their relationships and outcomes. So let’s get started with Introduction to BCD.

## Binary Coded Decimal (BCD) System

• We studied in previous articles about decimal, binary, and hexadecimal systems which are used to handle small numbers in plc.
• The binary-coded decimal scheme offers a suitable technique of managing huge statistics which used in plc as input and output.
• As in the last article about binary, decimal, and hex systems we studied that, there is no informal technique to vigor from binary to decimal and back from decimal to binary.
• The BCD (binary coded decimal) scheme offers a method of adapting a code freely controlled by persons (decimal) to a code freely controlled by the apparatus (binary).
• PLC (programmer logic controller) thumb-wheel buttons and LED (light-emitting displays) pageants are samples of PLC (programmer logic controller) expedients that mark usage of the BCD  (binary coded decimal) numeral scheme.
• Given a diagram, table displays samples of numbers values in decimal (10), binary (2), BCD(10), and hexadecimal illustration.
• The BCD (binary coded decimal) scheme usages four bits to signify every decimal number.
• The four bits cast-off the binary equals of the integers from zero to nine.
• In the BCD (binary coded decimal) scheme, the biggest decimal digit which can be showed by any 4 numbers is nine. How to convert BCD to Decimal

• The BCD (binary coded decimal) illustration of a decimal digit is attained by substituting every decimal number by its BCD (binary coded decimal) correspondent.
• To differentiate the BCD (binary coded decimal) number scheme from a binary scheme, a BCD (binary coded decimal) description is sited to the right of the number of the elements.
• The BCD (binary coded decimal) illustration of the decimal digit 7863 is given in the below diagram.

#### Role of BCD in PLC

• An input instrument of plc which uses BCD is shown in given diagram, it is a thumbwheel. In the given diagram single-digit BCD thumbwheel is shown.
• The circuitry panel connected with the thumbwheel has a single linking for every bit.
• The worker entered a decimal number between zero and nine, and the thumbwheel gives outputs to the equal four bits of BCD (Binary coded Decimal) information.
• In this instance, the digit 8 is entered to yield the input bit arrangement of thousand.
• A 4-number thumbwheel switch, like to the one presented in the diagram, would govern sixteen (4 3 4) PLC (programmer logic controller) inputs. ### BCD conversion in PLC

• PLC (programmer logic controller) comprises of integer alteration tasks which are shown in the given diagram.
• BCD (Binary coded Decimal) to binary alteration is requisite for the input whereas binary to BCD (Binary coded Decimal) alteration is requisite for the output.
• The PLC (programmer logic controller) change to decimal commands will change the binary number arrangement at the location of source ( N7:23), into a BCD (Binary coded Decimal) bit arrangement of the similar decimal assessment as the destination location, (O:20).
• The commands implement each time it is perused, and the command is correct. that is detail post about BCD used in PLC i tried to cover each and every parameter related to this post. If you have any further query ask in comments. Thanks for studying have a nice day. See you in next post