Programmable Logic Controllers (PLCs) often interface with various sensors, actuators, and other devices in industrial automation. The terms "sinking" and "sourcing" refer to the two main types of input/output (I/O) configurations used in these connections.
Sinking (NPN):
- In a sinking configuration, the positive side of the power supply is connected directly to the load (such as a sensor or actuator).
- The output of the PLC is connected to the negative side of the load and acts as a switch to ground (negative).
- When the PLC output is activated, it connects the load to ground, completing the circuit and allowing current to flow.
Sourcing (PNP):
- In a sourcing configuration, the negative side of the power supply is connected directly to the load.
- The PLC output is connected to the positive side of the load and acts as a switch to the positive voltage.
- When the PLC output is activated, it connects the load to the positive voltage, completing the circuit and allowing current to flow.
In summary, the distinction between sinking and sourcing lies in how the current flows through the circuit: in sinking, the current flows from the positive supply through the load to ground, while in sourcing, the current flows from the PLC output, through the load, to the positive supply.
The choice between sinking and sourcing depends on various factors such as the type of sensors and actuators used, compatibility with existing equipment, and the specific requirements of the application. Some PLCs support both sinking and sourcing configurations, providing flexibility in system design.
No comments:
Post a Comment