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Hello everyone, I hope you're doing well. 1. System Overview I am working with a Mitsubishi QJ71E71-100 Ethernet module and trying to establish communication using MC Protocol (Binary Mode) over UDP. My goal is to retrieve real-time data from a Q13UDEHCPU PLC and display it on a dashboard. 2. Current Network Setup PLC Model: QJ71E71-100 CPU: Q13UDEHCPU Communication Mode: MC Protocol (Binary/ASCII Mode) over UDP PLC IP: 192.168.22.51 PLC Port: 7000 PC IP: 192.168.22.100 PC Port (Listening for response): 9600 3. Current PLC Ethernet Settings Protocol: UDP Fixed Buffer Communication: Procedure Exist Pairing Open: Enable Existence Confirmation: Confirm Communication Data Code: Binary Initial Timing: Always wait for OPEN TCP Existence Confirmation Setting: Use the KeepAlive 4. Issue Description I have tried communicating with the PLC using both MC Protocol Binary Mode and ASCII Mode, but the response is always the same, regardless of the register I request. I attempted reading from D12001, D12002, and other D-registers, but the response remains unchanged. Additionally, I have received different response values (44303534 and 43303534), but the content of the data does not change. 5. Packet Details Below is the request packet I am sending: request_packet = struct.pack( "<4B H H H 3B B H", 0x50, 0x00, # Subheader (2B) 0x00, 0xFF, # Network Number & PLC Number (2B) 0x0C, 0x00, # Request Length (2B) 0x01, 0x04, # Command Code (Read Word Device - 0x0401) 0x00, 0x00, # Subcommand (2B) 0x01, 0x20, 0xA8, # Start Address (D12001 - 3B) 0x01 # Number of Words to Read (1B) ) When I send this request, Wireshark captures the correct packet format, but the PLC's response is always the same, regardless of the requested register. 6. Response from PLC (Always the same) Raw Response (HEX): 44303534 or 43303534 ASCII Interpretation: "D054" or "C054" I have also tried sending the request in ASCII mode, but the response remains the same. Regardless of whether I use Binary or ASCII communication, the PLC does not return the expected register value. 7. Steps Taken & Debugging So Far Verified that MC Protocol (Binary) is enabled on the PLC. Tried switching between ASCII and Binary Mode, but the response does not change. Ensured that the Ethernet settings match the MC Protocol requirements (Binary Mode, Procedure Exist, Pairing Open: Enable, etc.). Tested different D-registers (D12001, D12002, etc.) but always receive the same response. Checked Wireshark logs to confirm the correct packet is being sent. 8. Questions & Request for Help Why is the PLC always returning the same response (44303534 or 43303534)? Is there an additional setting required to enable proper MC Protocol Binary/ASCII communication? Is it possible that the PLC is still using a Fixed Buffer communication mode instead of MC Protocol? What additional debugging steps should I take? Any insights or suggestions would be greatly appreciated! I am not very familiar with English, so I used ChatGPT to write this post. Thank you for your understanding. 😊

I am trying to establish a Modbus connection from a laptop to a Mitsubishi inverter (FR A-800 E series) (the manual for this connection can be found [here][1]) I am using pymodbus and I can establish a connection, but the problem comes when I try to read a register. I know I am connection because doing something like: from pymodbus.client import ModbusTcpClient client = ModbusTcpClient('192.168.15.10', 502) client.connect() results in a True response. Also, if I just print `client` it returns the details of the connection, which makes me confident the connection is properly establish. But, whenever I try to read a register (which I am confident exists, since it appears in the manual) : result=client.read_holding_registers(9,1,1) print(result) I would obtain: Modbus Error: [Input/Output] Modbus Error: [Invalid Message] No response received, expected at least 8 bytes (0 received) and if I try again, Modbus Error: [Input/Output] No Response received from the remote unit/unable to decode response. Does anyone have any idea? I have tried with a bunch of addresses for the registers, I have tried including not including the 1,1) part when reading the register and got no luck. [1]: https://dl.mitsubishielectric.com/dl/fa/document/manual/inv/ib0600628eng/ib0600628engd.pdf)

Hi, I need to connect an FX3U Mitsubishi PLC with my raspberry for reading some data and put them into a charts. I was thing on using python but I'm not finding much help on how to do it. The PLC is even connected with an HMI GT1050-QBBD. I really appreaciate every kind of help you can give me. Thanks to all

View File Temperature measurement using Arduino Nano, RTD PT100 temperature sensor and 4-20 mA transmitter Temperature measurement usind Arduino Nano, RTD PT100 sensor, 4-20 mA current loop transmiter, and a python app for visualization Submitter Absolutelyautomation Submitted 04/01/2016 Category Other PLC Demo Software