Questions tagged [modbus]
Modbus is a serial communications protocol commonly used by PLCs (programmable logic controllers) and other industrial control systems. While originally based on traditional serial communication, many extensions exist to allow communication over other networks such as TCP/IP.
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I'm only able to read registers in groups [closed]
I'm integrating my power meter with the modbus interface with my smart home. I'm trying to read registries to provide data about current power usage, etc.
Is it normal that I'm only able to read ...
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Trouble connecting RS485 turbidity sensor to a Raspberry Pi
I am trying to connect a Turbidity sensor that operates using Modbus to a Raspberry Pi. The sensor is an industrial-grade device and comes with the needed communication protocols (http://www.sonbus....
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RS485 Communication Issue with ABB M4M 30 Modbus Using Waveshare RS485 CAN HAT on Raspberry Pi 5
I am using a Waveshare RS232/RS485 CAN HAT with a Raspberry Pi 5 running Raspberry Pi OS (Full, 64-bit) to connect to an ABB M4M 30 energy meter over Modbus RTU via Node-RED.
When I scan for devices ...
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Modbus RTU Sending 90% Gibberish, 10% Useful Data, & Inconsistent Working Addresses
I'm here looking for advice on 2 issues:
What could be causing the large volume of errors and incorrect responses being sent by an energy metering via RS 485 Modbus RTU to my Windows laptop (...
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Troubleshooting Inconsistent LoRa-DTU ↔ USB-LoRa Transmission over RS-485
I’m building a long-range wireless link to forward Modbus-RTU data from an MPPT charge controller over LoRa. I’ve wired up one SX1262-LoRa-DTU to the MPPT’s RS-485 bus and one USB-TO-LoRa-xF on my PC, ...
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Modbus RTU signal diagnosis?
I am trying to use Modbus communication between a PC Client and an arduino UNO R4 Minima server (with a Zihatek modbus shield). The Tx/Rx LEDs on the UNO and RS485 converter flash in sync and I am ...
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Modbus RTU Interference [closed]
I'm experiencing an issue with Modbus RTU communication and would like to describe the situation in detail.
I have a Modbus slave device from which I'm reading 16 analog inputs (ADC readings) and ...
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How do I debug Modbus timeout error?
I am an undergraduate researcher trying to connect my PC to a Eurotherm 3508 controller (see Eurotherm 3508 manual here: https://www.eurotherm.com/download/3504-3508-engineering-manual-ha027988-iss-19/...
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A question about Modbus request response time
In a Modbus RTU the master sends request it receives a response from slave. Im wondering if there is any term for this interval used in PLCs. We can restrict this question for now for one master to ...
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UART to Isolated RS485 port for modbus causing checksum error
I am trying to create a UART to isolated RS485 port to communicate over Modbus, both Tx and Rx LEDs are glowing together and I am getting checksum errors. The schematic is attached for reference. What ...
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Should a Modbus exception function code set the MSB or add 0x80?
Suppose a client initiates a transaction, sending a function code in the range 128..255. This function code is invalid, so the server should respond with an exception. However, to me it seems like the ...
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RS-485 Transmission problem (Modbus RTU)
EDIT: Problem was solved.
The baudrate from the moxa board had a mismatch of 5%, preventing proper transmission. The problem is not electrical but driver related, since by using termios and ioctl to ...
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Issue with MD02 Temperature and Sensor (MODBUS)
Have an issue with the MD-02 sensor
The sensor was working fine till I "tried" to change the slave address from 0x01 to 0x02 using the command as per the above datasheet.
The command ...
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Reading Data Using Modbus RTU Over RS-485 [closed]
I would like to receive data from E95-DTU-433L20-485 via Modbus RTU. I could not read data properly. Could you help me figure out what the problem with my configuration is?
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MODBUS protocol implementation over RS485 for HMI LCD
I am planning to use PICCOLO microcontroller where HMI lcd will be interfaced over RS485 lines. UART lines of microcontroller will be interfaced to LCD via MAX22501 Transceiver.
My query is can we ...
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