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Have a look at the Client response handling section here: https://pymodbus.readthedocs.io/en/latest/source/client.html

Thank you for the code. Is this the same exact code you're running on your PC successfully? You said the Omega2+ does not even connect. How have you determined this? Where in your code is it failing? Is an error code returned by one of the ModbusTcpClient functions? If so, what is the error...

Please provide as much detail and context as possible so that we are able to assist you further. Which Modbus library are you using? Can you post your code? Can you ping the Modbus servo drive from the Omega2+? When you got communications working with your PC, were you using the same Modbus...

Are you trying to communicate Modbus/TCP (Ethernet) or Modbus RTU (RS-485)? Are you using a Modbus library or have you written your own Modbus code? If it's Modbus/TCP, make sure that both devices have compatible IP settings (for example, one may be 192.168.1.100 and the other 192.168.1.101...

What is the vendor and model of the EtherCAT force/torque sensor? It's entirely possible that the EtherCAT cycle time is independent from the sensor's force/torque sampling. In other words, the sensor may be sampling every 333 microseconds and calculating a force/torque process value. But your...

Can you elaborate on this? The voltage levels are required to be within in a certain range by the RS-485 specification. Also, signal levels would not have resulted in receiving an echo of the request. Perhaps you are referring to the "A" and "B" terminal labeling? Because this is...

OK, let's go through this step by step. What were your results using a Modbus simulator program on a PC with a USB to RS-485 adapter to communicate to the E53? What did you do to change the 2-wire mode of the NI 9871 to ensure it is not receiving its own transmissions? Please try the...

The NI 9871 is a 4-wire full-duplex module, while the E53 is a 2-wire half-duplex device. I assume you've connected the NI 9871's TX pair (+ and -) to its RX pair (+ and -) in order to wire it to the E53. Therefore, the NI 9871 is very likely receiving its own transmissions, resulting in what...

The request and response you show are identical. It appears you may be receiving an echo of the request transmission, not a real response from the device. What are you using as a Modbus master? Is it a PC with a USB to RS-485 converter? Does the converter have an option (or jumper) to...

The datasheet shows the connection diagram (see attached). That sensor is a 4-wire PNP sensor. The difference between 3-wire and 4-wire is that 4-wire provides both normally open and normally closed outputs, while 3-wire provides only one of these (either NO or NC). You will likely only need...

From the ND30IoT's Service Manual (https://www.lumel.com.pl/resources/Pliki%20do%20pobrania/ND30IoT/ND30IoT_service_manual.pdf), Register 4002 is described as "Voltage on terminal 2" with a range of only 0...2 (0 - first L1 phase voltage, 1 - second L2 phase voltage, 2 - third L3 phase voltage)...

Nevermind, I found it in Section 3.1 of the Modbus Over Serial Line Specification and Implementation Guide V1.02. There's also a figure included: Now, keep in mind, the spec also states cable length limitations when using passive taps in section 3.4.3: This is consistent with RS-485...

Would you mind providing the page/section number in the Modbus standard (or other reference) that mentions this?

What do you have your Response Timeout setting set to in Modbus Poll's Connection Setup window? Do you still see timeout errors if you increase the Response Timeout? Just to confirm, are your two slaves set to different addresses?

I suspect the readings shown via M-Bus are correct, it just may be that those readings were from the past. Take a look at the "time point" values immediately after the "volume" values. Perhaps those are supposed to indicate when the volume was sampled. I would guess that the first "time point"...

Thank you for the additional data. In your M-Bus Data table image, for address 20, item No. 3, volume shows a value of 1030, but is actually scaled incorrectly. It should be 1.03. Similarly, for address 21, the volume shown is 576 but should actually be 0.576. There is an online M-Bus decoder...

I actually think 4-wire networks are more difficult to troubleshoot, at least from an installation perspective. Instead of mixing up just 2-wires (+ and -) now you could mix up any combination of 4 wires (TX+, TX-, RX+, RX-). Perhaps from a software developer's standpoint, it's simpler to...

This thread is from over 20 years ago. Chances are, the members who posted back then no longer frequent this forum and you're not very likely to get a response from them. But I'll try to answer your questions. You don't do any tuning for this as a user. The device manufacturer has to have...

@David_2, note that the meter the OP has uses the M-Bus (Meter Bus) protocol, not Modbus. M-Bus has its own unique 2-wire physical layer where the master modulates voltage to indicate Logic 0 and Logic 1, while the slave(s) modulate current. This is the reason for using the Relay PW60 media...

A multimeter set to current mode (or an ammeter) must be used in series. It is used to measure current flowing through a circuit without changing the circuit (at least, very minimally impacting the circuit). It has a very low resistance, so by connecting it in parallel, you are essentially...