All Questions
71
questions
2
votes
0
answers
34
views
rs485/modbus issue
I am trying to enable modbus RTU communication between 2 inverters.
Both are set up with unique IDs, 9600Hz, 1 stop bit, No parity bit.
I can communicate with 1 at a time, as shown below in the ...
- 21
0
votes
2
answers
115
views
Why are there two wires connected to each terminal of the RS485 port in energy meters
I want to connect the energy meters of our clients to a gateway so that the gateway can communicate with the meters using Modbus. I have visited several electrical rooms that have gateways installed ...
- 335
0
votes
1
answer
35
views
Can TCC-100/100I Series Industrial RS-232 to RS-422/485 converters with optional 2 kV isolation convert RS485 to RS232? [closed]
I want to convert RS485 to RS232 to connect it to a Moxa Nport 5610 - 16 port RS-232 Ethernet serial device server.
Can I use a TCC-100/100I Series Industrial RS-232 to RS-422/485 converter to convert ...
0
votes
1
answer
47
views
Pulling Receiver Enable Low for RS-485 Transceiver is being transmitted as a byte in Modbus packet
I am running into an issue where pulling RE low on my Max3441EESA is appearing as an extra byte in my Modbus message. I am currently testing the Modbus capability of my PIC32 MCU with a Modbus slave ...
0
votes
0
answers
121
views
Potential Reasons for Fault on RS-485 Transceiver
I am working with the MAX3441 RS-485 transceiver, but I have run into faults with the three transceivers I have tested, so I am wondering if anyone can shed some insight on potential reasons for the ...
2
votes
2
answers
190
views
Can I connect ten RS485 modbus kWh meters to one RJ45 modbus server? [closed]
If I have a fusebox with about ten/fifteen eastron sdm630 and Orno OR-WE-515 kWh meters with RS485 modbus, can I daisy chain ...
- 173
3
votes
2
answers
123
views
Hardware advice for communicating data between two different MODBUS protocols using RS-485
I am trying to build a small device that will act as translator between two devices having two different RS-485 MODBUS protocols. This device will store 4 different values from "Device 1" ...
- 33
0
votes
1
answer
252
views
Can USB-to-SERIAL dongle be used to drive an RS-485 transceiver?
Pictured below is a simple arrangement used to read the Temperature sensor from the PC. Standard/Protocol is MODBUS RTU RS-485 Half-Duplex.
I've used this arrangement with both modpoll.exe and ...
- 109
0
votes
0
answers
129
views
Modbus receiving same message as sent
I am having a problem when communicating with a Modbus slave.
I have made a circuit with the translator shown in the picture. UART2_RXD and ...
- 11
0
votes
1
answer
122
views
Modbus ASCII messages delimiter
I need to implement Modbus messages reception over UART. For RTU it's easy because UART on my uC has configurable idle receive line detection. However, for ASCII the task is tricky - the delimiter is ...
- 11
0
votes
0
answers
350
views
Modbus RTU on ESP8266 to control VFD
Hoping to get some help on setting up a NodeMCU (esp8266) with this 1 arduino library to control a Variable Frequency Drive (VFD).
I'm afraid to say that I almost need help from square one, as I'm ...
1
vote
1
answer
2k
views
Modbus over RS485 - no response from device
I am trying to connect to Epever Tracer AN Solar Charge controller from ESP32 using below Max485 module but I can't get any repsonse from device.
I was trying to use exactly the same setup mentioned ...
- 25
0
votes
1
answer
56
views
Is it advisable to make communication re attempts in modbus?
In my system, I know that the approximate response time between master-slave is 10ms, if the slave does not receive communication during those 10ms then it detects an error and the motors turn off.
Is ...
- 427
2
votes
2
answers
1k
views
Maxim MAX3485ESA+T vs SP3485EN-L/TR
I have a question about the MAX3485ESA+T RS485 Transceiver.
I ordered a PCB with a MAX3485ESA+T and the project doesn't work. The previous design was with a SP3485EN-L/TR and it worked well, but I had ...
- 31
0
votes
0
answers
312
views
How to identify Modbus device speed rate?
In particular how to identify it without causing device misbehaving.
Either new device is being connected, and master has no idea what baud rate the device is configured with (assume it knows about 8/...
- 7,120