CODESYS Forge - CODESYS Forge / Talk / Engineering 🇬🇧: USB Stick Detection

Reinier Geers - 2020-09-10

How can i detect that there is an USB Stick ? With windows is read the directory. But now they changed to LINUX. That doesn't work that way.

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nothinrandom - 2020-09-17

Are you planning to do anything with the USB drive (i.e. read/write to it)? Just to list usb devices, you just need to run command lsusb. To read/write from it, I would recommend that you set up partition automount so that it will appear automatically after reboot/startup. I am not sure of your experience with Linux, so more information is needed.

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- Reinier Geers - 2020-09-24
  
  I dont know nothing about Linux. Thats the problem. They changed from Windows CE to Linux. Most of it is working. But if i read a directory its not up to date. Pull out the stick. Then read the stick. it still shows a directory !!
  
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Reinier Geers - 2020-09-18

Isusb ?? is that a codesys command ? I programm Codesys. Than i want to detect if there's a stick inserted. Ive there it should show the directory. But somehowe linux is not up to date. If i read a directory. then pul out the stick. Then read the diretory. It still shows the directory even if the stick is pulled out.

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Chris.O - 2020-09-23

Hi,... quick and dirty... maybe something like this

code VAR_INPUT xEnable: BOOL; END_VAR VAR_OUTPUT xUSBisMounted: BOOL; END_VAR VAR scmd:STRING:='lsusb'; sStdOut: STRING (1000); Result: SysProcess_Implementation.RTS_IEC_RESULT; iFindUSB: INT; xError: BOOL; END_VAR IF xEnable THEN SysProcess.SysProcessExecuteCommand2(pszCommand:=scmd, pszStdOut:=sStdOut, udiStdOutLen:=SIZEOF(sStdOut), pResult:=ADR(Result)); //Check if min. 1 USB device is mounted IF sStdOut <> 'Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub$NBus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub$N' THEN iFindUSB:=FIND(str1:=sStdOut, STR2:='Flash Drive'); IF iFindUSB <> 0 THEN xUSBisMounted:=TRUE; ELSE xUSBisMounted:=FALSE; END_IF ELSE xUSBisMounted:=FALSE; END_IF IF Result <> 0 THEN xError:=TRUE; sStdOut:=''; ELSE xError:=FALSE; END_IF END_IF

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Last edit: Chris.O 2020-09-23
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- nothinrandom - 2020-09-23
  
  I would recommend just process everything via SysProcessExecuteCommand2, so you don't need to do post processing in CoDeSys. Example command could be something like this to exclude "Linux Foundation" and include "Flash Drive":
  
  scmd:STRING:='lsusb | grep -v "Linux Foundation" | grep "Flash Drive"';
  
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- Reinier Geers - 2020-09-24
  
  Thanks. i will try it.
  
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- Reinier Geers - 2020-09-29
  
  Thats working. But not every stick responce with :"Flash Drive"
  
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- Reinier Geers - 2020-09-30
  
  Im testing it. but its one long string. So i tried to set it to an array. But commands like LEFT en RIGHT are limmited to 255. is there an other way ?
  
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  - Chris.O - 2020-09-30
    
    What do you mean with long string? If you use the "grep" parameter it should't be so long.
    If string is longer than may try to delete the first part of the string which you do not need...
    Or you try to program your own String functions ;-)
    
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    - Reinier Geers - 2020-09-30
      
      sStdOut is 1000. So to long for LEFT or RIGHT. Limits from codesys.
      I try Everythink. Also Lookt for an Linux Cource. But a Cource would help me at the moment.
      
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      - Chris.O - 2020-09-30
        
        You can also limit sStdOut to 255.
        If you use
        'lsblk | grep "/media/sda" ; echo OK';
        
        you should get a string with something like that:
        └─sda1 8:1 1 14.7G 0 part /media/sda1
        OK
        
        This would be a string with 51 Characters... so no problem
        
        If you use LEFT / RIGHT / MID with a String (1000) I think it will only use the fist 255 characters... so should also work.
        
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        Reinier Geers - 2020-09-30
        
        LSblk gives only OK$N with or without an stick.
        
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        Chris.O - 2020-09-30
        
        Can you try the command inside a terminal like putty?
        What result is there?
        And If you try only lsblk? Is there nothing... or what is the return from linux?
        
        Last edit: Chris.O 2020-09-30
        
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        Reinier Geers - 2020-09-30
        
        Never used putty. i look into it. I tried to shut down codesys to get to linux. But that doesn't work the way like in Windows.
        
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        Chris.O - 2020-09-30
        
        OK, then may install putty to your desktop-pc and connect your sps to your desktop pc... with putty you will get connection to your sps (with the ip-adress) then you can log in with user and password (e.g. user = root and PW = root or something like this). THen please try your command lsblk
        
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        Reinier Geers - 2020-09-30
        
        putty gives : -sh: lsblk: command not found
        
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        Chris.O - 2020-09-30
        
        Ok.... may command df -h is working?
        
        Should give you something like this:
        Filesystem Size Used Avail Use% Mounted on
        udev 1.9G 0 1.9G 0% /dev
        tmpfs 383M 5.9M 377M 2% /run
        /dev/mmcblk0p2 27G 5.5G 20G 23% /
        tmpfs 1.9G 1.5M 1.9G 1% /dev/shm
        tmpfs 5.0M 0 5.0M 0% /run/lock
        tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
        tmpfs 70M 360K 70M 1% /var/log
        /dev/mmcblk0p1 511M 5.1M 506M 1% /boot/efi
        /dev/mmcblk1 30G 43M 29G 1% /media/sd
        tmpfs 383M 0 383M 0% /run/user/0
        none 120M 40K 120M 1% /mnt/ramdisk
        /dev/sda 16G 4.8G 11G 32% /media/sda
        
        In my case here /dev/mmcblk1 is my sd-card (mounted at /media/sd
        and /dev/sda is my usb-stick (mounted at /medai/sda)
        
        with command df -h grep /media/sda
        you should get
        Filesystem Size Used Avail Use% Mounted on
        /dev/sda 16G 4.8G 11G 32% /media/sda
        
        THis are 96 characters and you can search for /media/sda...or your usb-directory
        
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        Reinier Geers - 2020-09-30
        
        df -h is working. But cant find sda1.
        ill think find also is limited to 255
        i can see it in the string. Also tried an union. But that also not working properly.
        
        Last edit: Reinier Geers 2020-09-30
        
        usb.PNG
        
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        Chris.O - 2020-09-30
        
        Ok, sounds good.
        Try command: df -h grep "your path name"
        
        e.g. df -h grep /media/sda1
        
        Then string should be shorter and you can see more.
        
        please try inside putty df -h and have a look what is displayed.
        
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        Reinier Geers - 2020-09-30
        
        Thats working. Now the end question. Witch on is better. DF or lsusb . Df reads the directory. and lsusb an status. so i would think that its better to check a status every second then to read every second a directory.
        
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        Chris.O - 2020-09-30
        
        Ok great...
        I don't know what is the better way... I would use what works better... you can check if the cycle time of your task changes or your cpu load changes with this commands...
        
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Alternative way would be to detect the mounted folder of the usb-Stick.
In my case the linux system mount the usb-stick with "sda" inside the folder /media.
Means my path would be "/media/sda".

Then may be something like this: (In the programming part I think best would be a state machine)

code

VAR
Open_Directory:File.DirOpen;
    xOpenDir: BOOL;
    sDirName: FILE.CAA.FILENAME:='/media';
    hHandle: FILE.CAA.HANDLE;
    eErrorOpen: FILE.ERROR;
    xBusyOpen: BOOL;
    xDoneOpen: BOOL;
    xErrorOpen: BOOL;

    List_Directory:File.DirList;
    xListDir: BOOL;
    xDoneList: BOOL;
    xBusyList: BOOL;
    eErrorList: FILE.ERROR;
    DirEntry: FILE.FILE_DIR_ENTRY;
    xErrorList:BOOL;

    DirClose:FILE.DirClose;
    xCloseDir: BOOL;
    xDoneClose: BOOL;
    xBusyClose: BOOL;
    xErrorClose: BOOL;
    eErrorClose: FILE.ERROR;
    xBusy: BOOL;
END_VAR

//First open the directory "/media"
Open_Directory(xExecute:=xOpenDir, sDirName:=sDirName, hDir=>hHandle, eError=>eErrorOpen, xBusy=>xBusyOpen, xDone=>xDoneOpen, xError=>xErrorOpen);

//If directory is opened, check what folders are inside (note that DirList ned rising edge for every folder)
List_Directory(xExecute:=xListDir, hDir:=hHandle, xDone=>xDoneList, xBusy=>xBusyList, xError=>xErrorList, eError=>eErrorList, deDirEntry=>DirEntry);

//Then you need programming part where you search for the string "sda" or "sda1"... depending on your stick
//If you found it, stick is plugged. If you unplug your stick, usually linux will delete the folder "sda" or "sda1"

//At the end close the directory
DirClose(xExecute:=xCloseDir, hDir:=hHandle, xDone=>xDoneClose, xBusy=>xBusyClose, xError=>xErrorClose, eError=>eErrorClose);

Only an idea :-)

Reinier Geers - 2020-09-24

Thats the way i did it. open the director. If its shows an Error, then there is no stick. But the problem is . if i read a directory its not up to date. Pull out the stick. Then read the stick. it still shows a directory !!

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Chris.O - 2020-09-24

Can you post your code?

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USB Stick Detection