Siemens S7-1200 PLC communication with Sinamics V20 VFD via Modbus RTU protocol.

The Siemens S7-1200 PLC (Programmable Logic Controller) can communicate with a Sinamics V20 Variable Frequency Drive (VFD) using the Modbus RTU (Remote Terminal Unit) protocol. This communication protocol is a widely used, serial communication protocol that enables the PLC to exchange data with the VFD. The setup allows for the control and monitoring of the VFD's operations directly from the PLC, facilitating automation and control processes in various applications, such as conveyor systems, pumps, fans, and other motor-driven applications.
Key Components:
- **Siemens S7-1200 PLC**: A compact, modular PLC designed for small to medium automation tasks. It's known for its performance, versatility, and ease of use in implementing logic controls, motion control, and HMI integration.
- **Sinamics V20 VFD**: A basic, compact, and cost-effective drive from Siemens designed for controlling the speed of electric motors. It's used in a variety of applications, from simple tasks to complex processes requiring speed control.
- **Modbus RTU Protocol**: A serial communication protocol that allows the PLC to communicate with various devices, including the VFD, over a serial line. This protocol facilitates the exchange of data between controllers and devices in an industrial setting, using a compact, binary representation of the data.
Communication Setup:
1. **Physical Connection**: The physical connection between the S7-1200 PLC and the Sinamics V20 VFD is typically made using RS485 communication lines, which support the Modbus RTU protocol's serial communication.
2. **Configuration**:
- The S7-1200 PLC needs to be configured to communicate using the Modbus RTU protocol. This involves setting up communication parameters such as baud rate, parity, stop bits, and data bits, which must match the settings on the VFD.
- The Sinamics V20 VFD must be configured to operate as a Modbus slave device, with parameters set to match those of the PLC's Modbus master settings.
3. **Programming**:
- In the S7-1200, Modbus communication blocks are used within the TIA Portal software to facilitate sending and receiving data to and from the VFD.
- Control and monitoring commands can be programmed in the PLC to start/stop the motor, change speed, read fault statuses, and perform other operations on the VFD.
Advantages:
- **Flexibility**: The Modbus RTU protocol allows for easy integration of different devices, offering a flexible solution for automation tasks.
- **Cost-Effective**: Using Modbus RTU for communication between the S7-1200 and Sinamics V20 is a cost-effective solution, avoiding the need for additional communication modules or proprietary networks.
- **Simplicity**: The setup offers a straightforward approach to controlling and monitoring VFDs, making it suitable for a wide range of applications.
This communication setup between the Siemens S7-1200 PLC and the Sinamics V20 VFD via Modbus RTU protocol is an effective way to achieve precise control and monitoring of motor speeds, enhancing the efficiency and performance of automated systems.
Industrial Automation
PLC Programming
Modbus RTU Communication
Siemens S7-1200
Sinamics V20 VFD
Motor Control
Variable Frequency Drives
RS485 Serial Communication
TIA Portal
Control Systems Engineering