Plc uses STL instruction programming method - Database & Sql Blog Articles

Programmable Package SG-8018CA(SG7050C) 0.67M~170M

SMD aluminum electrolytic capacitor

Photocoupler

1. STL instruction

The step ladder instruction is referred to as the STL instruction. The normally open contact of the state relay using the STL instruction is called the STL contact, which is a "fat" contact. The circuit block driven by the STL contact has three functions, namely, drive processing for the load, and specified conversion conditions. And specify the conversion target.

The STL contact is a normally open contact connected to the left bus. When a step is active, the corresponding STL contact is turned on and the circuit on the right is processed until the next step is activated.

After a certain STL contact is closed, the load coil of this step is driven. When the conversion condition after the step is satisfied, the conversion is realized, that is, the state relay corresponding to the subsequent step is ON, and the subsequent step becomes the active step, and the original active step is simultaneously The corresponding status relay is automatically reset by the system program, and the SET contact corresponding to the original active step is disconnected.