Handling Errors in the Modbus Protocol


Being open, the Modbus communication protocol belongs to the most popular ones. It is widely used at industrial-sector facilities. Most of the time, the protocol is used to establish connection between different equipment units. Its primary purpose is data transmission.

While communication using the Modbus protocol is considered to be reliable, risks of getting errors cannot be fully excluded. Like with any system, one can face an unexpected situation here. We provide information on available error detection tools, error types and error code interpretation.

Error Types and Control Techniques

The Modbus communication standard offers two error check techniques. They are initiated by a master device, while a slave device is responsible for control. Essentially, all messages and each and every byte sent are checked. This can be a parity check or an LRC/CRC check sum.

During the data transmission, the following errors can be detected:

    • logical errors: they are detected using frame signs and the CRC-16-IBM check sum;
    • errors caused by distortions occurring during the communication by this protocol: they are detected when a message containing a certain error code is received.

Major Codes

Codes assigned can provide a user details on errors related to data transmission problems. This is why it is important to know how to interpret them. For example, let’s consider the most popular ones:

    • 01 – The device failed to process the function code;
    • 02 – The register address is unavailable;
    • 03 – The slave device value is invalid;
    • 05 – The request has been received, but its processing requires much time;
    • 07 – Long operation failure.

OPC Server for Modbus Protocols

On our website, you can purchase the licensed software. We offer you to try out the Modbus OPC Server prior to buying it. For this end, just download a free demonstration version, which has a limited usage period. Does this application meet all your requirements? Place an order on our website to purchase the software.

← All News