![Port Port](/uploads/1/2/3/9/123990296/770741678.png)
The truth is I dont know. I think it is weird that your software is seeing what looks to me like a blank response. But the serial port dump you posted looks like a full meter response. The response is in ASCII and not in Hex so all characters are not printed (see this post for details: ) But you can still see that in the first read you have 232.0 volts and in the second read you had 232.4 volts.
So the meter data is good, your software is just not able to access the serial data or to parse it. This is where you have to focus I would think. I would take a look at this page as it seems like it has good details about POSIX serial ports: Maybe you can explain more why you are limited to only C and what the limitations of your project are. Hopefully someone out there with even a slight understanding of C (more than me) can step in and post here. Good luck again.
The issue ended up being that the readyread flag is only emitted if theirs data to read. Cara mengecilkan ukuran file pdf. However I was sending the data too quickly for the external device to receive it.
This meant that some data was lost thus the device never recognised it as a valid command. This meant that it was still waiting for the message to finish, hence the 'IRPMJDEVICECONTROL (IOCTLSERIALWAITONMASK) UP STATUSCANCELLED COM1' error message upon closing the program. This also explains why their were no error messages with regards to writing data.
This also explains why the same program occasionally managed to read data, and at other times failed, (even without rebuilding the program, just re-running it.) When the data was read, the processor was more loaded, i.e. Programs running in the background. This meant that the data was transmitted more slowly and thus the external device could recognise the commands and thus reply.
Adobe photoshop cs6 3d extension free download. Hi everyone I am tasked with writing a simple program for communicating with a fuel-pump. I need to get information from it. I never communicated with a device before. This is my first time writing a program for communication with a device.
I have read lots of articles about RS485 communication but people mostly writes about how it works not much detail about how to communicate with the device using it. So i am having lots of confusions. I have a few questions regarding RS485 communication. How do i tell device to give me the information i want. How do i read info sent from device(probably using ReadData, but want to be sure). The data that is given to me contains what? Is it unique for each device or there is a standard for this Can you give a little example also.:) Thanks in advance.
Having done this myself, MANY times here is my advice: Yes the data is unique to every device. There is no standard format, speed, or serial port data format. All devices pick and choose so you cannot assume code from device A would have any hope of working with device B from a different manufacturer. As was mentioned RS-485 defines the electrical communication.
Provided you have a good 485 to 232 adapter it will look like RS-232 data to you both for send and receive. You mentioned you have an adapter from 485 to USB. This adapter will need to represent itself as a COM port for QSerialPort to access it. Ask JKSH says above, plug it in, then look for a new COM port using the available functions. The first place to start is to gather as much data as you can gather. Find the manual, search for the part number, somewhere hope that you can find some info about what to expect.
Failing that you just have to do some trial and error:. Try common baud rates: 4800, 9600, 19200, 38400 and within those baud rates you'll need to try different data sizes 7 and 8 and different parities. When you have it wrong the data from the pump will be gibberish. When you get it right it may still not look like much but it should become more recognizable. Once you think you are onto the right speed and other settings see if you can actually figure out where the desired data is in the number. It could be ACSII so you could easily view it or it could be binary where having the manual will be a big help. But even if you can't find the manual if you can get the device to start sending you data then you can examine the input bytes for a change as your pump changes.
Sometimes you can use that to figure out what kind of data you are getting and how to convert it. The simple fact is that if you have the manual about the protocol most of this can be done in a couple of hours. If you don't then it is a bunch of trial and error and it could take you days or weeks to try enough combinations to end up with some data and then you've got to interpret it.
For stuff like this I made up some hardware to allow me to monitor the communications. If you have an existing working system and you do not have information about the protocol this is the best way to figure out what you need to send and expect for a response.
Qt Serial Port Rs485
Likely the communication would include some sort of target device address or identification as a minimum. RS-232 is not compatible on the electrical side. It might appear as a serial port through software in which case QSerialPort should work. Rondog is right.
I've done this before as well. You can purchase expensive RS-232 sniffers and monitors but frankly you can generally do what you need using a spare computer with two serial ports and some software. It takes a bit of work but you write software that reads all incoming data off one port and after logging it some how writes it out to the other port. If your device uses hardware signals like CTS, RTS, etc you will need to have your software read those changes and translate them over to the output port. Of course most serial stuff is bi-directional so you'd need to have a similar process going the other way.
As Rondog says if you are into building hardware you can build something that does all of this and perhaps sends the logged output to a serial port on your computer or over USB. Said in: Having done this myself, MANY times here is my advice: Yes the data is unique to every device. There is no standard format, speed, or serial port data format. All devices pick and choose so you cannot assume code from device A would have any hope of working with device B from a different manufacturer. As was mentioned RS-485 defines the electrical communication. Provided you have a good 485 to 232 adapter it will look like RS-232 data to you both for send and receive. You mentioned you have an adapter from 485 to USB.
This adapter will need to represent itself as a COM port for QSerialPort to access it. Ask JKSH says above, plug it in, then look for a new COM port using the available functions. The first place to start is to gather as much data as you can gather. Find the manual, search for the part number, somewhere hope that you can find some info about what to expect. Failing that you just have to do some trial and error:. Try common baud rates: 4800, 9600, 19200, 38400 and within those baud rates you'll need to try different data sizes 7 and 8 and different parities.
When you have it wrong the data from the pump will be gibberish. When you get it right it may still not look like much but it should become more recognizable.
Once you think you are onto the right speed and other settings see if you can actually figure out where the desired data is in the number. It could be ACSII so you could easily view it or it could be binary where having the manual will be a big help. But even if you can't find the manual if you can get the device to start sending you data then you can examine the input bytes for a change as your pump changes.
![Rs485 Rs485](/uploads/1/2/3/9/123990296/511480771.jpg)
Rs485 Serial Interface
Balam pichkari jo tune mujhe mari mp3 song. Sometimes you can use that to figure out what kind of data you are getting and how to convert it. The simple fact is that if you have the manual about the protocol most of this can be done in a couple of hours. If you don't then it is a bunch of trial and error and it could take you days or weeks to try enough combinations to end up with some data and then you've got to interpret it. As far as I understand, RS 232 and RS 485 are electrically different, but from the Qt's point of view, QSerialPort can handle both of these serial ports right? QSerialPort is sufficient for RS 485?