I am sending data from TCP to RS485 serial port using the following scheme:
computer <--> TCP/RS485 adapter <--> RS485 relay
source code:
QVector<quint16> vdata(4);
...
QModbusDataUnit adu(QModbusDataUnit::Coils, deviceAddress, vdata);
...
auto *reply = modbusDevice->sendReadRequest(adu, deviceAddress);
sended data:
qt.modbus.lowlevel: (TCP client) Sent TCP ADU: "00000000000801050010ff008dff"
qt.modbus: (TCP client) Sent TCP PDU: 0x050010ff008dff with tId: 0
Since the relay works on RS485, the data "1050010ff008dff" should go to it.
How can I send only "1050010ff008dff" instead of "00000000000801050010ff008dff" using Qt Modbus?
Devices can exchange data via QTcpSocket:
QString d = "01050010ff008dff";
QByteArray b = makeRTUFrame(1, ui->sboxFunc->value(), QByteArray::fromHex(d.toLatin1()));
tcpClient.write( b );
But the program needs to communicate in Qt Modbus.
I searched for a solution on google search engine and stackoverflow. None of the provided answers helped solve this problem.
Any support appreciated.
Thanks in advance.
Related
I'm building a project where I use 2 ESP8266 and 1 ESP32 devices, where I collect data with sensors on ESP8266's and send those gathered data to ESP32. Then, this ESP32 device sends an HTTP request (w/ HTTPClient) to my NodeJS Web Server, with the data received, which will eventually be processed there and saved to the database.
I'm having a problem though; when I use some mock data, and use only ESP32 without ESP-NOW and any other connection with other devices, I get status code 200, which indicates that my HTTP Request is sent succesfully. And when I use ESP-NOW to establish conenction between ESP devices, and not send any HTTP Request, I can successfully send and receive data.
However, when I use ESP-NOW to send and receive data, and send the data using HTTPClient request to my Web server on ESP32, I get status code -1 (refused connection). I couldn't find any other issues regarding this topic, so I figured I might ask for some help.
I have also used painlessmesh library to send/receive data between ESP devices, but that gave me the same exact issue. I'm using Wifi mode STA on my ESP32 device, which I connect it to my router to connect to the internet.
Thanks in advance for any help and support.
You cannot use ESP-NOW and WiFi in parallel at the same time; it's either-or. Exception: if you use the same channel for both (may not be possible)!
Option 1
You can alternate between the two protocols. So, as soon as the ESP-NOW transmissions from node 1 has completed (data fully received) you turn off ESP-NOW, connect to WiFi, publish via MQTT and then reverse. Needless to say that while your ESP32 is on WiFi you cannot receive data via ESP-NOW from either node 1 or node 2.
Option 2
Use some sort of gateway between ESP-NOW and WiFi. This product for example contains two ESP32 (connected over UART), one for ESP-NOW, one for WiFi: https://thingpulse.com/product/espgateway/. Disclaimer: I am a ThingPulse co-founder.
It is possible to run a web server and esp_now in the same esp32. Check my code here https://github.com/Servayejc/esp_now_web_server for the server
https://github.com/Servayejc/esp_now_web_server for the sender
This code make also automatic pairing of the nodes of esp_now.
This code is based on randomnerdtutorial…
Is it possible to get sensor output from Arduino via Ethernet connection and to send data to Arduino via Ethernet?
So basically can "replace" serial port with Ethernet port?
The typical way to do this is with an Arduino Ethernet shield, a small hardware module that plugs into your Arduino board:
http://arduino.cc/en/Main/ArduinoEthernetShield
Updated:
One very common approach for client to server communication would be to use HTTP over TCP/IP. See this example on the Ardunio site of a simple client on an Ardunio connecting with a server (in this case google):
http://arduino.cc/en/Tutorial/WebClient
For your use case you can simply create your own server and modify the example to send data to it.
Alternatively you can skip the HTTP part and just use sockets - there is an open source example here:
https://github.com/billroy/socket.io-arduino-client
I have a processing sketch that pumps out basic serial commands to an xbee.
Then I have two (soon to be 3, maybe 4) arduino's with their own xbee's who receive the data and do stuff.
Thing is each Arduino has it's own purpose, and therefore it's own data packet.
So, to implement this. Is there a way to send a message to a particular xbee? I.e. can I assign the xbee an index or channel of some sort, then get the broadcasting xbee to send data to whatever index or channel it needs to?
Or, will this need to be implemented in the Arduino software?
i.e. Processing prefix the data packet with an index/identifier and the arduino ignore incoming messages with that prefix?
Or is there another option entirely :P
Thanks in advance for your advice.
While not a specific answer to your question, with this type of communication some packet error checking would be beneficial. Send the data using a crc error checking algorithm. Packet structure could look something like:
0x7F 0x02 (Address Bytes) (Command Bytes) (CRC bytes) 0x7F 0x03
Where 0x7F is the DLE character used to indicate either a start byte will follow, and end byte will follow, or a data byte with the value of DLE will follow. This means any DLE character that is part of the address or command should be preceded by a 'Stuffed' DLE character. The CRC is calculated from the address and command bytes and used to check the integrity of the data that is received. The CRC check bytes are included in each packet.
This type of communication will prevent packets going to the wrong source from being used, and also packets that are in error from being used.
To read more on serial framing here is a good place to start: http://eli.thegreenplace.net/2009/08/12/framing-in-serial-communications/.
To what i understood is that you want to be able to tell the diffrence to what Xbee you are sending data to. You can do this by using IP adresses. If you have for example two Xbees with the IPs:
Xbee1 - 192.168.80.50
Xbee2 - 192.168.80.51
Xbee3 - 192.168.80.52
You can send information between them by just connecting the Xbee that will start the communication to the Xbee that will receive it. If you want to have any kind of communication over the wireless network (or ethernet) you must have an IP assigned to every Xbee.
EDIT:
If you have a server on a computer that you have made yourself in for example Java. You can connect the Xbees to that and connect of them to the computer server. Then you can set up the server to receive and send data to the diffrent Xbee clients.
I did something similar to this: Maintaining communication between Arduino and Java program , but i didn't use a Xbee, i used the official WiFi shield.
Hope this helped!
-Kad
I have used the following sequence of command on a wavecom modem, so far I have determined that sending the last one seems to reset the device, while sending the others works fine. I have done it using a freescale jm128 micro controller. The funny thing is that if I do it using docklight it works perfectly. I think it resets because when communicating with the modem using docklight after the micro controller sends the whole sequence of commands, I find that it has ignored ATE and AT+CMEE=1, that is to say, I still get echo and don't get number codes for the errors. Any help will be greatly appreciated.
ATE //suppress echo
AT+CMEE=1//details on errors
AT+WIPCFG=1 //start IP stack
AT+WIPBR=1,6 //open GPRS bearer
AT+WIPBR=2,6,11,"APN" //set APN of GPRS bearer
AT+WIPBR=2,6,0 //username
AT+WIPBR=2,6,1 //password
AT+WIPBR=4,6,0 //start GPRS bearer
AT+WIPCREATE=2,1,"server_ip_address",server_port //create a TCP client on port "server_port"
AT+WIPDATA=2,1,1 //switch do data exchange mode
Solved: First of all I changed the cable used to connect the modem with the microcontroller,
I used a db9, crossed 2 and 3 (rx and tx), put 4 and 7 pins to gnd, and didn't connect
pins 1, 8,9. Second, I changed at+wipdata= 2,1,1 to at+wipdata=2,1,2. It worked fine. I used
a Q2687 sierra wireless modem. Hope this helps someone who finds the same problems I found.
I've been trying to do TCP communication using my Wavecom Fastrack modem. What I want to achieve is make the modem connect to a specified TCP server port to enable me to transfer data to and from the server. I found some information on than in the user's guide.
Basing on the information you can find on page 66 I created an application that opens the serial port to which the modem is connected and writes the following AT commands:
AT+WIPCFG=1 //start IP stack
AT+WIPBR=1,6 //open GPRS bearer
AT+WIPBR=2,6,11,"APN" //set APN of GPRS bearer
AT+WIPBR=2,6,0 //username
AT+WIPBR=2,6,1 //password
AT+WIPBR=4,6,0 //start GPRS bearer
AT+WIPCREATE=2,1,"server_ip_address",server_port //create a TCP client on port "server_port"
AT+WIPDATA=2,1,1 //switch do data exchange mode
This is exactly what the user's guide says. After the last command is sent to the modem, the device switches to data exchange mode and from then on everything what is written to the serial port opened by my application should be received by the server and everything the server sends should appear in the input buffer of that port.
The thing is that I did not manage to maintain stable bidirectional communication between the server and my modem. When I write some data to the serial port (only a few bytes), it takes a lot of time before the data appears on the server's side and in many cases the data does not reach the server at all.
I performed a few tests writing about 100 bytes to the serial port at once. Logging the data received by my server application I noticed that the first piece of data (8-35 bytes) is received after a second or two. The rest of the data appears in 2-5 seconds (either as a whole or in pieces of the said size) or does not appear at all.
I do not know where to look for the reason of that behaviour. Did I use wrong AT commands to switch the modem to TCP client mode? I can't believe the communication may be so slow and unstable.
Any advice will be appreciated. Thank you in advance.
what OS are you running? Windows does a pretty good job of hiding the messy details of communicating with the GPRS modem, all you have to do is create a new dial-up connection. To establish the connection you can make a call to the Win32 RasDial function. Once connected, you can use standard sockets to transfer data on a TCP port.
i have been using wavecomm modem for 2 years now.As far as i know from my experience is that if you are able to send some of the data then you can send all of the data.
the problem might be in the listening application which receives the data on the server side.
It could be that it is unable to deal with the amount of data that you are trying to send.
try sending the same data in smaller busts
with some delay in between them,then you might receive all data intact.