Siemens PLC, SCL instruction table is a collection of instructions used to write programs in the SCL language. It contains a variety of instructions for controlling and operating the PLC, which can realize data management, data computing, process control and other functions. Here's an example of a simple SCL instruction list:
1.Contact commands: LD, A, O, LDN, AN, ON
ld, enter a normally open contact connected to the busbar, that is, the normally open contact logic operation begins.
LDN, enter a normally closed contact connected to the busbar, that is, the normally closed contact logic operation begins.
a, with instructions. For a single normally open contact ground in series.
an, with non-directives. For the series connection of a single normally closed contact.
o, or directives. For parallel connection of a single normally open contact.
on, or non-directive. For parallel connection of a single normally closed contact.
2.Data, processing instructions:
MOV: Used to copy a value from one variable to another.
add: Used to add two variables together and store the result in one variable.
sub: Used to subtract one variable from another and store the result in one variable.
3.Count ** Count Instructions:
mul: Used to multiply two variables and store the result in one variable.
div: Used to divide one variable by another and store the result in one variable.
mod: Used to calculate the remainder of the division of two variables and store the result in one variable.
4.Process Control Instructions:
if…then…else: Used to perform different operations based on conditions.
for…to…step…next: used to execute a block in a loop.
while…do…end while: used to execute a block in a loop based on conditions.
This is only a small part of the SCL instruction table, and there are actually many other instructions that can be used in the SCL language. By combining and nesting these instructions, complex control programs can be written to meet a variety of needs.