When a character appeared reading serial port

Similar Questions

• reading serial port control

  I am trying to establish a connection to an external device via the serial port. This is done in a while loop that sends a request to the association is trying to get a response if a response is not received a new rewuest is sent, etc. At the present time, this procedure does not work. I am considering two explanations for this. The first is that the loop does not wait long enough for a future response and continuous pumping motions, the other is simply that there is something wrong with the algorithm of reading, which don't take correctly into the serial port information.

  Have you even considered that the "application of the association" that you send is not correct. More often than not, the reason why you get nothing to read is because you not write properly. You have not posted anything related to this function and display of an image is not the best way to get help in this matter. For certain types of entries, it is important to determine whether your control/string constant is set to normal display, '-' display Codes or hexadecimal display.

• reading serial port constantly and update the string buffer

  Hi guys,.

  I am facing a problem in reading the data in series using LabVIEW.

  I have an unknown size of data to be read on the RS-232 (Serial) and using read write serial.vi (example) I have read the data permanently and monitor for chain DONE on the buffer, but the channel indicator that displays the output not updated data.

  Chain should:

  1 2 3 4

  5 6 7 8

  I don't see one character at a time on the indicator.

  This is the screenshot of the vi

  

  Is there any method which will help me to do this?

  Hi Dave,.

  Thanks a lot... you helped me finish all my work... "Always small things blink quickly.

  See you soon,.

  Sailesh

• serial port read one character

  Hello

  I'm new to the forum, so I don't know if I'm posting this question in the right place.

  However, my problem is I'm trying to communicate via serial rs-232 port and the goal is to read and write the question (code) of the device.

  The Unit regularly sends a "perpetuate" character S. When I read this character, I write the question and receive the response. Then a S appears again and I bravado the code, read the answer and so on...

  The problem is that when I try to do everything at once (read S, send the code and read the answer) and it 14 times before reaching the 1st code again once, labview is very slow. (3-5 seconds to perform this tasks 14 and restart the process). I think that the program becomes slow because that way I'm not using all the S which inflamed the writing and reading process.

  So, I wanted to read character by character (byte-by-byte) and then create a table with the answer. The problem is that the buffer sends answers with several bytes and I can't build an array in 'real time', beacause if I read (read VISA) only one byte, then I would be lost all the others.

  I think that chains concantenate and shift registers are part of the solution, but I have too many problems until I get to the part.

  So, please help me to read a single character and doesn't lose not the other bytes sent by the buffer, in order to fix the process, because I want one second per second refresh. The device emits a flow rate of 19200 baud.

  Thanks in advance

  I think that if you connect the value 1, the reading serial port function, you will receive a byte, and you won't lose the rest.

  The rest are stored in the buffer. If you use the previous function again, you will get the next byte.

• Add serial port to VM, get BSOD 0x0000007b

  The operating system is Windows XP and it has been converted from a physical PC about 2 months ago.  He was the starter and working for all of the two months.

  But this computer starts.  I have a snapshot that I can surely return.  And this snapshot successfully starts and restarts.

  But when I add a single serial port (which is a physical port mapping) you get a BSOD on startup.

  After getting the BSOD, if I remove the newly added serial port, he continues to get the BSOD... safe mode or not.

  I am able to join the 'hard drive' to another 'computer' and read / copy files.

  No minidump file is generated by the BSOD.

  I read through all the STOP 0x0000007B VMWare community articles.  While I'm sure it's related to that those who are all about the SCSI drivers and boot devices.

  He is a serial port...

  Someone at - it a theory or something to try?

  OK, so far, I've saved a copy of the VMX for bootable and BSOD.

  A diff seems to indicate that SCSI is get added.  I will try to reduce the VMX BSOD and see what happens.  I might be able to save myself, but feel free to drop some knowledge on me if you have one.

  As well as it did.

  I have nuked two SCSI lines out of the VMX file and it starts.

  scsi0. Present = 'TRUE '.

  scsi0.pciSlotNumber = "16".

  Don't know why VMWare 9 added THAT SCSI on a computer virtual set to IDE... perhaps that will happen every time I have to change the settings.

  Don't know...

  This virtual machine was a horrible time, conversion from physical to virtual and it never worked when trying to make the recommended patches SCSI community.

  Maybe when life slows down I'll clone and try to convert them into SCSI again.

• VISA from read/write to serial port - unable to implements several orders of writing!

  Hello

  I'm new to Labview and I'm reading from a pressure through a virtual serial port USB sensor. I am able to read the port when you use HyperTerminal

  The code sequence that I should write to the port in order to obtain measurements using hyperterminal is the following:

  ' *' (2A hex)-online start and the responses of the port by asking 'Command', I should then enter

  FF-online measurement select the port must ask the 'mode', so I should enter

  0 has-online measurement of high resolution mode and it was then that I should start receiving action.

  The port is always answer by errors when I write the start command or the FF one. I tried to establish a sequence stacked to write the three commands then read the port, I added some delay between the three of them, but it does not work.

  Now I made really simple and removed the stacked sequence and just put the three commands one after the other and try to remedy not to not on the code.

  I'm really stuck at this point, could someone help me please? I read a lot fo articles on the forum, but I can't solve this problem

  Thank you

  I have attached my VI and the SCP1000 documentation (I can provide other versions of my demo if necessary)

  The reason for your problem is a frequent misunderstanding even among experienced programmers. Take a look at this thread

  http://forums.NI.com/NI/board/message?board.ID=170&thread.ID=417750

  In your data sheet, then they return codes like 0xFF or 0x0A so has a single byte of average value. Then you in your-active code constant writing FF\n is so this equal to values in format hexadecimal 46460A and your instrument do not understand. But it will include FF0A. In order to solve your problem, you would type in \FF\n in your '-' chain helped codes. Remember too, if you type in \32 it will be converted to character 2 this being 0 x 32 50 decimals and code ASCII 50 is equal 2

  Take the time and change the display format of string between '-' display and Hex display and you will see the difference

  Hope this helps

• Problem: read bytes to serial port

  Hello, I need to communicate with an external device with serial port. I have to write a command to my device string, and then it should play with 64 bytes of data. I built a function of READING-WRITING and I use it in a loop (I have to read a lot of 64-byte block)

  Sometimes, I have the following problem:

  (1) I have send the command string, I wait with "Bytes to the serial port" whereas I have more then 60 bytes, then I read.

  (2) sometimes happen that the read function cannot read all 64 bytes, so the net for cycle, I have in the receiver buffer mor than 64 and the program to stop working. (does not work well)

  I need to be sure that after writing the command I have 64 bytes, so I red all the 64 bytes so the next loop for, I have the buffer of the empty receiver.

  I enclose my writing reading function. Please refer to the block diagram (there are a few notes).

  Thank you

  In no place in your program see the VISA configure the Serial Port. It's always a good idea to include this that even if you use the default settings. I suspect this is one of the default settings which is wrong with you. By default, playback is set to end when a character is considered. This means that if you have a 10 hex (ASCII LF) in your stream, playback stops until the specified number of bytes is read. Put in a VISA set up the Serial Port and connect a constant False to the stop character allow entry.

• Read the Serial Port with termination Char?

  Hi, I have a particular piece of hardware that I'm communicating which sends a stop character 0xAh at the end of the data written to the port. I have trouble reading the data from the port where I only get half of the data due to synchronization problems. I know that it's related to be looking at the bytes to the port property node and read the bytes that probably replacing end setting tank. I have the correctly defined termination char, so, how did a survey for serial data to the port without using the bytes to the port method because I don't think that it works when you use the termination char port method. Anyone know this issue?

  Simple VI that explains what my main VI by defining the term tank and using the bytes to the method of port that is not working properly and causes problems of loss of data from mark is attached.

  Thank you.

  
  

• Parity errors & read on Serial Port framing

  Hello, I am writing a program that reads the serial port IR thermometer. Intermittently I get parity so many framing errors and can't explain why or find a way to remedy. All the parameters of the series were double checked and controlled. I don't get any errors when you use HyperTerminal yet, when I do test bed in MAX, I see these mistakes from time to time. I tried the suggestions of the knowledge base for these as presenting a delay between the Visa set up and read the Visa or flushing buffer issue before reading, but none worked. Any idea or ideas would be appreciated.

  In addition, while searching through discussions on parity and framing errors, I saw a when a user recommends the following: "use wait event triggered by the stop character and when the error occurs, I just deleted the error, empty the buffer (wait the next stop character) and reread." If that sounds like a good solution, how would I go about its implementation?

  I've attached a screenshot of my reading series loop so you can see what I'm doing. I do about the error code control timeout is.

  Given that you have activated the stop character, you should not use the bytes to the serial port. You shouldn't have to delay or any function buffer flush.

  PS, You also have to change the way your loop exits.

• Sometimes the lost bytes, reading the serial port

  Hello!

  I'm reading the serial port data (flow rate 57600 baud rate) that works very reliable so that I do not open any other window

  or minimize/restore my window of the application during the program is running. Then a byte of incoming data will be lost.

  I get a string of 30 bytes each 50 m in most of the cases the first byte is lost, sometimes one in the middle.

  This occurs not only on a PC.

  Is this a problem of LabVIEW or Windows?

  Are there settings that can solve the problem?

  Best regards

  JK78

  I solved the problem.  

  There was a bug in my program who become visible only if a window has been reduced or restored.

  When there are two or more messages in the buffer VISA, the separation of the messages was incorrect.

  Array index corresponded to false so that the first byte of the second message was at the end of the first

  and so the second message in the buffer seemed incomplete.

  In normal operation, the playback loop runs so fast, never both messages are in the buffer.

  Thanks for all replies.

  JK78

  Either way, I work with LabVIEW 2009 and serial interface hardware motherboard. With XON/XOFF flow control

  is not possible in my application because all the hex values from 00 h to FFh may appear in a message.

• Questions about serial port read and write at the same time

  Hi I create a user interface for the communication serial port, where there are essentially 2 front panels, where the user enters commands one and the other where the prints of UART is delivered. I thought initially using a state machine but the reading and writing may be independent sometimes and so I can't rely on States. I searched a bit on the forum and he left me even more confused. Help, please.

  (1) in a thread that sessions visa duplicated has been used for writing and reading at the same time, is it recommendable? How will this affect performance?

  (2) essentially when the vi is reading data are it must constantly view as well, however, someone said that it takes too much memory to use shift registers, so how do I go about this? If using a State in queue after the loop of reading it affects the playback loop and be sequential?

  In addition anyway is to move the cursor to the latest data from the indicator

  (3) for the control of the user input, assumes that the user has entered an order in the control and press ENTER, then writing visa is launched, but if it comes in another string and press enter then write must be called again... is - it possible? will detect the previous commands in the control of compensation?

  (4) according to my understand the expectation for the event do not monopolize resources and writing can go in parallel, am I right?

  Thank you. I have attached a very basic vi which took me to the point, but I want to make it more robust. Please help especially in the part of the user interface.

  su_a,

  (1) you can have only one session to a port. Several UART can handle full duplex so performance is not affected.  At flow rates of high data and large amounts of data, buffering and latencies of BONE can become a problem.

  (2) who told you that shift registers using too much memory? Shift registers are usually the best way to transfer data from one iteration to another. String concatenation inside a loop (registry to offset or not) causes the chain to develop and may require re-allocation of memory.  Your VI never clears the string so its cold length become very large.

  Generally, you do not have an active cursor on an indicator.  If you want to always display the most recently received characters and turn on the vertical scroll bar use a property node to keep scrolls to the bottom.  This can be annoying for users if they attempt to manually move the scroll bar and find that the program continues to move it back automatically.

  (3) if the user has changed the value in the chain of command, when he hits enter the modified value event fires.  Simply strike brace does not change the value and does not trigger the event.  Not control need to be erased, but the value that he has to change.  If you want to send the same command again, have a button send a command may be a better choice.

  (4) write is a case of the event.  It is not in parallel with anything.  The structure of the event do not monopolize resources.  The other loop will run while it waits.

  The event loop will not stop when you press the STOP button. Probably it wll take two command: change events of value after JUDGMENT before any loop stops.  Replace the Timeout event (which never expires) with a STOP: value change event and a real wire of this judgment to the Terminal endpoint.  Remove the local variable.  Make mechanical locking when released.

  Lynn

• Error reading the port series when the hexadecimal value is 0d (carriage return)

  Hello

  I'm reading a string of 80 bytes from the serial port, but if one of these bytes is 0d (hexa) the rest of the bytes are not read because the read node Visa sees the value 0D as ASCII for the return shipping. How can I read the entire string and see the 0d as a value and not as a symbol of the ASCII?

  Manual

  Of course, she sees it as a carriage return and ends. That's what you have programmed to do. The "character of endpoint allows" set to false with your VISA to set up the Serial Port. What Steve has already said. Claire?

• How use the serial port read and display the text but not scroll off the screen?

  I'm new-ish/return user fan of Labview and trying to change the example VI "Advanced serial write and read VI" is the part of the dev suite 2012.  I need to use the string box for ALL of the text from a serial port, always adding and just roll off the screen when the actuals come to the serial port.

  What actually arrived more than bytes (or no bytes AT ALL!), during reading time text, current rolls out of the box in the chain.  Even when receiving 0 bytes, screen is removed.  I'm not very familiar with the locations of functions and even worse to understand obscure references to functions, so please keep very basic answers so I can follow.

  Just to be clear, I need window of the chain behave as HyperTerminal does always displays the data and it is not pushed by window arbitrarily.

  Thank you

  Steve

  A long shot.

  Is that what you want?

• What functions can I use to read from a RS-422 serial port?

  I'm reading a continuous strem of three numbers of an anemometer connected via RS - 422. What is the easiest way to read these in LabVIEW? Also it would be easy to separate these numbers andplot them separately against the clock?

  Dear

  He's hit 422 network operations and Miss at best. We decided to use their equipment to convert RS232 RS422 but only use an intrument on each 422 network. So we didn't need mark of unity, we use a serial port, separate for each instrument. I just configured to run in default mode on several occasions where they send their status message. The default mode also transmits all three (if you use patterns 3-axis) for the playback speed.

  When operating in this mode and configuration, everything I have to do is surround data and analyze the updated.

  This screenshot should show you everything you need to get started.

  

  Have fun!

  Ben

• Serial port buffer - how to read the last entry?

  Hello

  I'm trying to read data from a device connected to the serial port. The instrument makes a row of data, last updated CR LF at pre-set intervals (0.2 seconds, 0.5 sec., etc.). I want to read the most recent line to an interval of time different (for example 1 s). What happens is that the buffer fills, and when I read that I always get the whole buffer content, starting with the first (oldest) row of data.  After reading, I empty the buffer to prevent overflow.

  From the red string I, I serach occurrence of CRLF and take the data before the game. This will give me the first line of data (oldest), sometimes incomplete.

  What I want is the last line. There must be an easy way to achieve this?

  I can't use the Frother with my instrument.

  Any help appreciated

  Sylvester

  To give an idea, put something like this you diagram: