How to Communicate with Sensors via Modbus

Anthony Smith
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See how to take measurements from infrared temperature sensors using Modbus software, with examples

The Modbus communication protocol is used by many industrial devices, including the Calex PyroMiniBus infrared temperature sensor. This powerful protocol allows hundreds of sensors to be connected to a single network, with robust industrial-standard communications.

Our own Modbus Master hardware provides a simple temperature display and configuration interface with no need for any knowledge of Modbus programming, however you can alternatively use third-party Modbus software to take temperature measurements and configure the sensors.

When using a third-party Modbus Master, the sequence of hexadecimal code in each Modbus message can initially seem difficult to decipher, but with a little knowledge of the structure of the Modbus commands and responses, it is easy to understand.

This practical guide explains the "need to know" information to configure a Modbus Master, and includes examples of "read" and "write" Modbus commands in hexadecimal.

Calex PyroMiniBus infrared temperature sensors with 6-channel PM180 Modbus Master interface module
Calex PyroMiniBus infrared temperature sensors with 6-channel PM180 Modbus Master interface module

The flexible PyroMiniBus system combines miniature infrared temperature sensors with built-in RS485 Modbus communications, and optional interface modules for local display and data logging. Sensors can be connected directly to any RS485 Modbus RTU Master, or via the optional local displays.

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