MODBUS RTU help needed


Thread Starter

Chris Ferrell

Guys I need help. I'm a HVAC controls contractor and I have a constant issue with MODBUS RTU and my ability to connect to an MODBUS capable device. I want to be able to walk up to a device, (IE Rooftop HVAC unit, Data Center UPS unit) and connect to it with my laptop and see basic things.....It it addressed it communicating at all....can I poll a register...Can anyone help with this?

You can use the Modbus Tester as the master.

If you want to find the communication setup (slave address, Baud Rate, Registers range, etc.) you can use the Modbus Scanner.
The programs you can download from

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