what are the languages used in plc(programming logic control)?

Answer 1

Industrial PLC's are commonly programmed in Ladder Logic which is a graphic oriented programming method is designed to mimic an electrical ladder wiring diagram. Ninety percent if not more of PLC's are programmed using Ladder Logic.

PLC's require a PC or laptop to use the ladder logic programming software. There are hand held programmers which use simplified commands to program the logic. (This is not assembly code) Handheld controllers have the advantage of being smaller and convenient to use in the field.

As laptops are common place the use of hand held programmers is greatly diminished.


Some PLC's incorporate C or BASIC style programming incombination with graphic programming. The ABB mod30ML PLC is a great example of this as its programming software allows the use of Expression Blocks which allow users to write a small amount of C like code.

There are some PLC's which are programmed in BASIC. THe Parallax Basic stamp is sold in a rugedized version as a PLC. Also Blue Earth Research markets Micro controllers and an industrial controller programmed in Tiny Basic...

Answer 2

A programmable logic controller, also called a PLC or programmable controller, is a computer-type device used to control equipment in an industrial facility. The kinds of equipment that PLCs can control are as varied as industrial facilities themselves. Conveyor systems, food processing machinery, auto assembly lines…you name it and there’s probably a PLC out there controlling it.
In a traditional industrial control system, all control devices are wired directly to each other according to how the system is supposed to operate. In a PLC system, however, the PLC replaces the wiring between the devices. Thus, instead of being wired directly to each other, all equipment is wired to the PLC. Then, the control program inside the PLC provides the “wiring” connection between the devices.
The control program is the computer program stored in the PLC’s memory that tells the PLC what’s supposed to be going on in the system. The use of a PLC to provide the wiring connections between system devices is called softwiring.

1- there are 3 methods for programming PLCs:
the first and the main is Ladder programming: Early PLCs, designed for the car industry, replaced relay control schemes. The symbols used in relay drawings, –] [– for a normally open (NO) contact, –] / [– for a normally closed (NC) contact, and –( )– for a plant output, were the basis of the language.

2- the second is Logic symbols: Logic gates based on TTL (transistor–transistor logic) and CMOS (complementary
metal oxide semiconductor) integrated circuits are widely used in digital systems (including the boards used inside PLCs). The circuits used on these boards are represented by logic symbols, and these symbols can also be used to describe the operations of a PLC program.
Logic symbols are used by Siemens and ABB; initially we will use Siemens notation.

3- the third is Statement list: A statement list is a set of instructions which superficially resemble assembly language instructions for a computer. Statement lists, available on the Siemens and Mitsubishi range, are the most flexible form of
programming for the experienced user but are by no means as easy to follow as ladder diagrams or logic symbols.

Answer 3

There are more than one languages that are used in PLC programming. Ladder Logic is the most commonly used PLC programming languages. Apart from Ladder Logic, SFC(Sequential Function Charts), FBD(Function Block Diagram)), ST(Structured Text), IL(Instruction List) are the other languages that are mainly used for programming. The multiple language can be used within the same programmable controller. This facility is useful for the developer to select the language that best suited to the particular task.

Answer 4

The primary language a PLC understands is "Assembly Language".
But you seldom have to use it, because there are so many programming editor software titles out there, running on a PC (or Mac), which have an Assembler "built-in".
Those come in BASIC, C, PASCAL, C++, Java etc., and I have even seen some in Ladder Logic and Flow Chart input.
But if you want to manipulate bits rather than bytes, then its back to assembly language.

Answer 5

older plc's use assembly language; I have seen a few that use ladder logic and some more advanced ones using JAVA but these require connection to a pc for the non pc ones its assembly lang