I'm using Python 2.7, pySerial under windows 7.
I have 8 devices, they are connected to my PC via Virtual COM port (Silicon Labs CP210x USB to UART Bridge), I'm testing them With multiprocessing all 8 COM ports are open and each time i'm sending command to one unit only, there is no MultiThreading.
The problem is that after X time (it could be 10 minutes or 5 hours), the output Queue of the serial ports fails to send me responses. it's not a specific port each time it's a different port (it can be several ports)
It's importent to say, the device gets my command and do it. the fail is to get the response, The device i'm testing is OK for sure.
I am sniffing the port with Serial monitor, all the commands send OK and the device makes them, only it doesn't respond.
Any idea's ?
There could be n number of reasons:
Buffers might be full
Com Port is not working or might be
And finally the device is malfunctioning..
Check out these things might be it will help you.
Related
Currently I have a server, that communicates with a projector through a RS232. The server opens a com port when the projector is connected. The same happens to any PC when a certain type of device is connected through the USB (lets say an Arduino for example). What I want to do it basically replace the projector with a PC/Arduino/Raspberry without the server noticing anything. That would mean the server will recognise the connected PC and open a COM port for it. What do I need to do on the PC so that it automatically opens a com port on the server? I guess there is something very basic that any printer, Arduino, projector etc does, that computers recognise it as a "com port device".
P.S. Doesn't matter the OS on the PC, I just need to make it work and then implement w/e I need to do with the established communication over the port.
P.S.2 I've searched a lot about it, but probabl I am doing it wrong, because I didn't find my type of question anywhere.
COM ports are basically hardware that is detected by the system. Let's say, if an Arduino is connected to a PC, it has its onboard USB to TTL converter which can be found in the device manager(if using windows). Similar USB to TTL converters are there in the market like CP2102, PL2303 which acts like a COM port even if no device is connected further to it. it may be possible that the program you are using(as you referred server) may be sending some data over the serial port and verifying the hardware.
What you need to do to replace it is, first of all, find the baud rate at which the communication is going on, then, listen over the serial lines which machine is sending which message in the sequence(there must be a handshake as I mentioned earlier), if a complicated algorithm is not used by the device, you can simply mimic the device by sending same messages over serial.
I have 3 xbee receiver devices connected to Ubuntu on port ttyUSB0, ttyUSB1, ttyUSB2. Out of these 3, device on ttyUSB2 stops working after every 2-3days. When I open xctu, it shows below error:
Could not find device on port /dev/ttyUSB2. Error initializing xbee device parameters. Connection timeout. Could not read device information.
When I type ls /dev or lsusb, I can see all 3 devices connected and all the 3 serial ports but the device on /dev/ttyUSB2 doesnt respond. When I unplug it and plug it back, it starts operating normally. But again after 2-3 days, it stops responding.
Can anyone please suggest what could be the issue.
I had the same problem. Turned out another program (Cura / Creality Slicer, in my case) was intermittendly checking the serial ports for connected devices, which (I assume) interrupted serial communication for XCTU.
Closing the other program solved the issue.
I am controlling a device over serial connection using LabVIEW (version 7.0). It is connected using USB, and is installed as a virtual serial port on the computer (running Windows XP). Every now and then my device crashes when my program sends a command, and it is unable to accept any more input (the device itself also stops working) until it has timed out.
I've looked at the serial port traffic using Portmon. Whenever the device crashes the serial driver sends the command I send using my program four times instead of just once, with an IOCTL_SERIAL_GET_COMMSTATUS command in between. I cannot see what this last command returns, but I assume something happens in the communication earlier on. I'm thinking my configuration of the port is not entirely right, but I have no idea how or why. I open and close the connection to my device every time I want to write something to it.
For completeness' sake: it has a baud rate of 9600, 8 bits, no parity, 1 stop bit, and no flow control. I'm aware that the correct settings of these parameters depend on the device, but the manufacturer has not supplied any recommended settings.
The driver is a DLL of some sort? If so, this is the most likely source of your problem, and you likely will need to contact the author of the driver. LabVIEW does have crashing bugs, but by far the most common source of crashes in simple communications apps is a buggy third-party DLL.
In other words, I doubt this is a LabVIEW problem at all and that you would have the same difficulty if you wrote a C program to talk to this driver. I only know what you've posted here about your system, but after many years of chasing down such issues, I would start with the device manufacturer/driver author.
If you have evidence to the contrary, please share.
I have a Microsoft Surface Book that I've dual booted Linux Mint on. I'm writing a program that needs to read in data from a serial port, but my serial ports don't seem to be working. The behavior is consistent across Mint and Windows (Testing done through Cygwin). It gets a bit of data the first 2-5 seconds that the device is plugged in (viewing the data through screen, same thing happens if I just use pyserial to print data incoming from serial port), then nothing.
What could be happening? I think I've isolated the problem to the serial ports - the Surface Book has 2 USB ports and the same thing happens on both of them, and I've tested the hardware that I'm plugging into it on 2 other computers (One Linux and one Mac OS), and it works fine on both of those.
Your MS Surface, seemingly, has a yellow triangle exclamation mark icon (over the adapter icon) without any driver to install/download. And properties in the device status box window say This device cannot start. (Code 10) or A device which does not exist was specified. Right?
If it's so you should wait for an update from MS. It's notorious problem.
I ended up getting the computer replaced on warranty for an unrelated issue months later, and what do you know, on the new computer the serial ports work fine. That indicates to me some sort of hardware problem, given that the issue persisted across OS's.
maybe this will help:
see Arduino examples for serial port communication - search google:
arduino serial c++
arduino serial c#
arduino serial c++ linux
the point is to open port properly you need to open a file, not a port. not with usual c - assembly write to port code.
another option you are using an unintentionally bought fake USB to serial cable with a Fake PL2303 chip
then you need to install the old version of the driver.
search in google:
Fake PL2303 + your os name:
install driver Fake PL2303 windows 10
another option is maybe it conserves energy and closes the port because it feels it is unused.
in windows> device manager,> properties of a device - usually USB root hub > power management - allow the computer to turn off this device to save power - uncheck it.
https://superuser.com/questions/408683/why-my-usb-mouse-gets-suspended-after-3-seconds-of-inactivity
https://blogs.msdn.microsoft.com/usbcoreblog/2013/11/08/help-after-installing-windows-8-1-my-usb-device-doesnt-charge-or-it-disconnects-and-reconnects-frequently/
also, you could look in windows events - to see what happens. usually, failures like this are registered in the events log.
an unlikely option is it consumes too much current, like a short circuit. and the device protection circuit shuts the chip off. also probably it does not have such circuit. one possibility is to try with an external powered hub.
the most probable of these is the power saving mechanism
I was experiencing the same problem - came across the solution on another site. The USB 3 ports on Surface Book aren't compatible with something or other to do with Com Port but running the device through a cheap USB hub solved my problem straight away and it was instantly recognised by the Arduino IDE
I'm new to serial communication. For a project I have to develop software for a vending machine. The vending machine basically consists of a host computer (a windows xp machine) and various peripherals. One of those peripherals is a coin acceptor. According to the documentation of the vending machine, the host computer communicates with the coin acceptor using the serial port. The only documentation I have is this document called "Multi-Drop Bus / Internal Communication Protocol" (the version I have can be found here: http://www.coin-acceptor.com.cn/Upload/EditorFiles/technicalfile/Mdb_version_4-2.pdf).
According to the docs it seems I have to create a serial port connection using a baud rate of 9600, 1 start bit, 1 stop bit, 1 mode bit and 8 data bits (page 29 in the linked document). The vending machine docs state that the coin acceptor is on COM port 6. I tried to create a connection like this using HyperTerminal and Putty. My first question is:
How do I properly create a connection to a device that supports this MDB 'protocol'? Putty and HyperTerminal don't allow me to set a "mode bit". I didn't find anything about the flow control and parity bit in the document. Can this be done using Putty or HyperTerminal? Or do I need some other tool to communicate over MDB?
My second question is about how to send a command to the device. I looked through the commands and saw a RESET command. According to the document, upon receiving the RESET command the device should reset itself and respond with an ACK. According to pages 33 and 63 of the document, if I want to send the RESET command to the coin acceptor, I can send the HEX value 08H over the serial line. Page 33 states that the coin changer listens to commands sent to addresses 08H until 10H (if I'm interpreting the document correctly, that is). Page 63 states that the RESET command is 08H with no data bytes. So can I just type "08H" into Putty and hit "enter" to send this command to the device? Or how can I send this command to the device over the serial line? Is this even the right approach or am I looking in the completely wrong place? The vending machine docs only contain this document for the coin acceptor. Thank you for the help!
Kind regards
Chris