Siemens S7 Read

This function block facilitates communication with Siemens S7 PLCs (Programmable Logic Controllers) by reading various data types from specified data blocks within the PLC.

📥 Inputs

Enable A boolean input that allows enabling or disabling the reading operation from the PLC.

S7 Client A generic input representing the connection details required to communicate with the Siemens S7 device.

📤 Outputs

Data Provides the data read from the specified data block in the PLC, corresponding to the selected data type.

🕹️ Controls

DB Number A textual input field where you specify the data block number from which to read.

DB Byte Address A textual input field to input the starting byte address within the data block.

DB Data Type A dropdown menu allowing you to select the type of data to read, such as Boolean, Int, DInt, Real, etc. Available types are predefined.

🎨 Features

Flexible Data Access Users can read various data types from different data blocks within the PLC.

Error Handling Robust logging against potential read errors or connection issues provides real-time feedback.

Dynamic Connection Management Automatically reconnects to different PLC devices when the address changes.

📝 Usage Instructions

1. Enable Reading: Set the Enable input to true to allow the block to initiate a read operation.

2. Input Connection Details: Connect the S7 Client input with the connection parameters of the Siemens PLC.

3. Specify DB Number: Specify the desired data block number using the DB Number input field.

4. Set Byte Address: Input the byte address to specify from which point in the block the data should be read.

5. Select Data Type: Choose the appropriate data type for reading from the dropdown menu.

6. Run the Block: When executed, the block will read data from the PLC based on the provided parameters and output the result.

📊 Evaluation

The function block retrieves and displays the specified data from the Siemens S7 PLC when executed successfully.

💡 Tips and Tricks

Understanding Data Types

Ensure that the data type selected from the DB Data Type dropdown corresponds accurately with the data stored in the PLC. Mismatching types can lead to unexpected results or errors.

Checking Connection Status

If you experience issues reading data, confirm that the PLC is connected and accessible. Utilize the logging features to identify connection errors.

Efficiently Handling Busy Server States

If you encounter a "server busy" warning, consider implementing retry mechanisms or extending the read interval to allow the server time to process previous requests.

🛠️ Troubleshooting

Server Not Connected

If the error message indicates the server is not connected, verify the connection settings passed through the S7 Client input. Ensure your PLC is powered and properly configured.

Invalid DB Number or Byte Address

Ensure that the DB Number and Byte Address provided are valid and exist in the PLC configuration. A wrong configuration will prevent data reading.