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According to that documentation, the Battery Capacity is a 16-bit integer, not a 32-bit floating point value. Therefore, your query frame should be as follows (note that the number of registers is 1, not 2): 01 03 00 57 00 01 35 DA From your original request/response for reading registers...

The Modbus specification defines a register as a 16-bit value and specifies that each register must be encoded using most-significant-byte-first ordering in the Modbus packet. The specification does not define 32-bit values, nor how they should be encoded in the Modbus packet. Therefore...

No, it is not expected for there to be that long of a delay for a RS-485 to Ethernet gateway. There is likely a configuration setting that needs to be modified. Here are some additional details, for context. There are two types of protocol converters: routers and gateways. A router simply...

Well, for what it's worth, it seems you're not the first to have a problem like this: https://community.st.com/s/question/0D50X0000AhO13O/freertos-lwip-freemodbus-tcp-hanging As suggested in that forum, are you able to debug the issue to determine what leads up to the crash and what exactly the...

Modbus/TCP doesn't have a slave ID. Only serial line Modbus has a slave ID. There is a Unit ID field in Modbus/TCP, but this is not quite the same and is typically only used by Modbus routers when routing the packet to a Modbus RTU or Modbus ASCII serial line. What Modbus command are you...

Many Opto 22 products support Modbus RTU natively or with an integration kit. Have a look here https://documents.opto22.com/2011_Using_Modbus_Devices_with_Opto_22_Products_Tech_Note.pdf and here http://documents.opto22.com/1820_Communication_Protocols_for_Opto_22_Products.pdf

I think your general idea is correct. There are a few corrections and suggestions I can make, though. Since you're using Modbus RTU, the packets will probably be stored in a byte array, not a string, since Modbus RTU is a binary protocol. There is an ASCII version of Modbus, fittingly called...

I'm sorry, but I am not going to decode this for you. I will say, though, that not all of the packets you show are even valid Modbus packets and they don't even seem to correspond to matching requests/responses between a master and slave. You can decode these yourself by following the Modbus...

Judging by the packets shown in this capture, the RX packets are requests and the TX packets are responses. The device that the RX and TX are in relation to must be a Modbus slave device. The packets you show in this image consist of requests for function code 16 - Preset Multiple Registers to...

The bytes you've shown correspond to a request packet, not a response. It's a request to device 12 to read 10 Holding Registers starting at 40271. 1. Slave Id-0C 2. Function Code-03 3. Starting Register Address-010E 4. Number of Registers-000A 5. CRC-EFA4 Note that the register address encoded...

Many of our (ICC) gateways support a Modbus RTU Sniffer driver that allows passively listening in on the Modbus communication between a master and one or more slaves in order to "sniff" the data exchanged. This driver is frequently used for multi-master applications where one or both of the...

To actually calculate the CRC (for verification, etc.), you can use an online CRC calculator such as this: https://www.lammertbies.nl/comm/info/crc-calculation Note, though, as stated in the spec David linked, the CRC is encoded low byte first then high byte in the Modbus message, so the CRC...

I recommend first following the instructions in the WP8025ADAM manual for using Wellpro's PC debugging tool to confirm operation between your PC, USB to RS-485 converter, and the WP8025ADAM module. Next I recommend trying a third-party Modbus tool, such as Modbus Poll, to read and write the 8...

You can use ICC's free Modbus Master Tool to log Modbus RTU data to a CSV file on a computer. The Modbus Master Tool is available here: http://www.iccdesigns.com/software/43-icc-modbus-master-tool.html There are also tutorial videos available here...

I think these are the relevant lines from the install log for the error. It seems you have Microsoft Visual Studio 2010 installed on your computer and the installer is failing trying to add integration for TwinCAT to it (TwinCAT is based on Visual Studio). If you don't use or need Microsoft...

Your attached file doesn't look like an installer log, so unfortunately it does not provide any useful information. Try redownloading and extracting the TwinCAT installer from Beckhoff's website. Also, try disabling any anti-virus software that could interfere with the install. If that still...

Try restarting your computer and run the installer again. If it still doesn't work, check the "Show the Windows Installer log" checkbox and attach the log file.

If you think of this in terms of separating your Modbus application from the TCP connection, I believe the answer should become clearer. Focusing on the Modbus application layer, if your device is a client, it will send a request message to the TCP layer and start its timeout timer. If your...

When you say you're able to access the board on your local network, do you mean you are simply opening a web browser and typing in the relay module's IP address? Or do you already have Modbus software on your computer/phone/tablet that you can turn relays on and off with via WiFi on your local...

I think the problem is that what you've shown here from the manufacturer is not Modbus, even though that may be what the manufacturer claims. It is similar to Modbus, so maybe they tried to implement Modbus, but did it incorrectly. For the "4) Set the target volume" request and response, here's...