Variables

Naming Rules

1. Always start with a lowercase letter.

2. Subsequent words start with uppercase letters.

3. Do not use underscores _.

4. Numbers from 0 to 9.

5. 🐫 Lower camel case.

   variableName

6. ❗ If the variable is related to Safety, the name starts with F_:

   F_variableName

Examples

VAR
  // ✅ Correct:
  isRunning: bool;
  ready: bool;
  inHomePos: bool;
  runForward: bool;
  status: int;
END_VAR

VAR
  // ❌ Wrong:
  is_Runing: bool;
  READY: bool;
  in_home_pos: bool;
  Run_Forward: bool;
  Status: int;
  ...
END_VAR

When to use _ in a variable?

In principle, we DO NOT recommend the use of the underscore, unless the declared variable needs a semantic separation for structuring and the variable cannot be placed in a structure.

Example

We have motor1 which has the properties isRunning, ready, warning, and error. For various reasons, let’s assume we cannot create a motor1 structure. In that case, and only in that case, we advise using the underscore.

VAR
  // ✅ Correct:
  motor1_isRunning: bool;
  motor1_ready: bool;
  motor1_warning: bool;
  motor1_error: bool;
END_VAR

VAR
  // ❌ Wrong:
  motor1IsRuning: bool;
  motor1_Ready: bool;
  motor1warning: bool;
  error_motor1: bool; 😭😭😭
END_VAR