What are PLC languages used for programming?

What are PLC languages used for programming?

IEC (International Electrotechnical Commission) Section 61131-3 Standard following languages used in programming:

1. Ladder Diagram (LD)

2. Functional Block Diagram (FBD)

3. Sequential Flow Chart (SFC)

4. Structural Text (ST)

5. Instruction List (IL)

1. Ladder Diagram

Ladder is work in left power rail to right power rail, top to bottom.

ladder logic as same as a electrical relay logic concept.

All the input connection as connected to the left side of ladder programming and output connection are connected to the write side of connection in ladder diagram

Input connect as NO/NC contact.

Output connect as COIL.

2. Functional Block Diagram

Functional Block diagram indicated the programming used in block for the operation. 

It is function between inputs and outputs that are connected in blocks by connection lines.

Left side of programming used the conditional functional block & output side indicate the output of the functional block.

It easy to used the programming.

At one logic created used in multi-pal time.

FBD programming is difficult to troubleshoot that is the major disadvantage. 

2. Sequential Flow Chart

Sequential Function Charts use steps and transitions to achieve your end results.

It can be faster to design and write the logic 

Equipment are directly connect to logic, so direct access of equipment faulted find.

Most of time PLC Programming Language does not always fit every application that is disadvantage.