How to Parse Floating Point Data in MODBUS

HongKe Technology

01

However, this process faces the challenge of data parsing: the application of floating point data must follow the IEE745 data conversion rules to achieve conversion and utilization with integer data.

Registers can only store 16-bit data, so floating point data will be split into two parts, stored in adjacent registers, as follows:

1. When reading data, the two register data need to be parsed back into floating point data (as shown in Figure 1);

2. When writing data, the floating point data needs to be parsed into two hexadecimal values to be written into the respective registers (as shown in Figure 2).

Figure 1. Register data merged into floating point data

Figure 2. Floating point data written to registers

02

To address these issues, HongKe provides a parsing method, as follows:

1. Read two register data and merge them into floating point data using bitwise operations.

2. Write a floating point data by splitting the 32-bit floating point data into two 16-bit integer data using bitwise operations, and writing them into two registers.

03

The Industrial Raspberry Pi uses a Debian system, which is highly open-source and can be programmed using C/C++, Java, C#, Python, etc. There are many methods to convert floating point data into hexadecimal integer data and parse it, and the above is just one of the data parsing methods. This method has a margin of error of ±0.01 and can be applied in scenarios where the precision requirement for floating point data is not particularly high. For other parsing methods, engineers are welcome to add WeChat for communication.

04

HongKe’s Industrial Raspberry Pi products feature a real-time Raspbian system, built-in Broadco multi-core processors capable of handling complex tasks such as image processing.

Additionally, it is compact, flexible, low power consumption, supports development using Python/Java/C/C++/C#, Node-RED visual programming tools, and can achieve CPDESYS soft PLC functionality. It helps users quickly create applications in data acquisition and small control scenarios, realizing industrial IoT and digital production.

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