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Thank you for the traffic view. That looks quite different from the previous traffic you posted from Modbus Poll. The traffic view shows that the CRC is indeed incorrect. The last two bytes are the CRC. In the top captures, it shows 5d ff, but the CRC should actually be 5d 01. Similarly some of...

What is the USB to RS-485 adapter you're using? From your initial screenshot of Modbus Poll, it shows "USB-SERIAL CH340 (COM3)". I assume this means you're using something based on the CH340 chip. What does the traffic view (Setup->Display Options->Show Traffic) show in ModScan when requesting...

The Status Register (Holding Register 1) is only 1 address (a single 16-bit register). You should be able to read that register by itself. And although some Modbus slave devices return an error when reading only one register of a two register (i.e. 32-bit) value, many, if not most, do allow...

OK, great. That confirms hardware and communication settings. For what it's worth, the packets you're seeing in PuTTY each look similar to this: ▒ 2 -10123D ▒ - Is likely the STX character (0x02h) 2 - is the <status> (a value of 2, i.e. Bit 1 set, means Stable weight) -1012 - is the weight...

I suggest trying the following to confirm proper connections and communication settings. Set the DAT11's COM2 Protocol to Continuous Transmission so that it will continuously transmit the weight string. Use a serial terminal emulator, such as PuTTY or Terminal by Bray++, to view the ASCII...

Do you have any termination resistors installed or termination enabled on any of the devices (DAT11, PLC, USB to RS-485 adapter, etc.)? If so, try removing/disabling all termination to see if that resolves the issue.

It seems like there could be noise on the RS-485 lines (possibly from lack of a common ground reference) or perhaps the DAT11 device is constantly transmitting (it's COM2 protocol may be set to continuous or automatic transmission of the weight string, despite you trying to configure the...

I'm not quite sure what you consider a session, but I'm not sure you're going to find anything like that for Modbus RTU. The closest thing, in my opinion, would be to split frames based on the address of the target device. You could then further split frames by function code. Be aware, though...

The King Pigeon device is a Modbus/TCP server. You need to develop a Modbus/TCP client to read registers from the King Pigeon device. I suggest taking a look at this python library: https://pymodbus.readthedocs.io/en/latest/source/readme.html Note that some Modbus devices use 1-based register...

That's going to depend on the specific BMS or SCADA system. You should be able to extract bit flags from Modbus registers using any BMS or SCADA system that supports Modbus. Typically, the bit flags would be extracted and mapped to boolean tags (one flag per bit flag). Note that your energy...

Previously you were asking about reading the Alarm flags, which is a 64-bit unsigned bit flag register at address 0x8A25 (35,365 decimal). This is different from the event codes that you are now asking about. If you look right above the table from your picture in the manual, it states: The...

In Modbus Poll, go to Display->Binary and click Binary. If you want Modbus Poll to decode individual bit flags, select the value of interest in the table and click Display->Binary->Show Binary Names. Note that this only works for standard 16-bit registers, so for the 64-bit flags, you will need...

ModSim supports the full addressing range (1 - 65536). Note that you do not enter the 400,000 offset in ModSim, but rather select Holding Register as the Modbus Point Type. https://www.win-tech.com/ Also, Modbus Slave (from Witte Software who makes Modbus Poll) supports 6 digit addressing...

Two things: The Active energy register is a 64-bit unsigned integer. The value spans 4 registers (as indicated in the Nr of registers column), which would be registers 20480 - 20483. Try selecting one of the 64 Bit Unsigned options (probably the Big-endian option) in the Display menu in Modbus...

For PLC's specifically, there's the PLCS.net forum here: http://www.plctalk.net/qanda/ You could also try asking questions here on this forum under the PLC's section: https://control.com/forums/forums/programmable-logic-controller-plc.14/

I'm sorry, but I don't fully understand your description of the issue you're having. Are you saying you are trying to write a value to your slave using ModScan32 and that ModScan32 seems to indicate the write was successful, but your slave does not show the new value after the write? Can...

If cheap is what you want, here's a suggestion: https://www.waveshare.com/product/iot-communication/wired-comm-converter/usb-to-rs232-uart-fifo/usb-to-rs232-485-422-ttl.htm In addition to RS232/485/422 it also has TTL (switch selectable 5v or 3.3V). It also has built-in termination resistor...

One word of caution with that Microflex converter, assuming my theory is correct. I would be wary of using it for any BACnet MS/TP communication or testing, as MS/TP is very timing critical and has a specified maximum drive time.

Thanks for the update. So the issue was simply selecting the wrong number of stop bits (1 versus 2) in the communication settings. Did you confirm again that the Microflex converter works with 1 stop bit to rule out the possibility you had simply selected 2 stop bits when using that converter...

The ESP32 is a microcontroller, so have you written (or obtained code or a library for) a Modbus driver to run on the ESP32? Are you using Modbus/TCP (Ethernet connection) or Modbus RTU (serial connection)? Do you see an error message in ModScan32? Have you searched the Arduino forum for...