What kinds of programming languages are commonly used in PLC?

Ladder diagram programming: The advantages are image, intuition and practicality. It is well known to electrical technicians and is the main programming language of PLC.
Instruction statement language: Similar to the mnemonic language in a computer, it is the most basic programming language for programmable controllers. The so-called instruction statement table programming is to use one or several easy-to-remember characters to represent some operation function of the programmable controller. Each manufacturer uses different mnemonics, so the sentence form written by the same ladder book is different. Statement is the basic unit of user program, and each control function is executed by one or more user programs. Each statement is an instruction that specifies how the CPU operates. Its function is the same as that of the computer. Moreover, the statement of the PLC is also composed of operation codes and operands, so its expression is similar to that of the computer instruction.
Sequential Function Flow Chart: A relatively new programming method. Its function is to express a sequential control process with a function diagram. SFC is used as a step-by-step control language, which can control a control process and display the state of the process. The logic of user application is divided into steps and transformation conditions to replace a long ladder diagram program. The display of these steps and transition conditions enables the user to see what state the machine process is in at a given time.