Serial port bert

I planned to start with some guidance on how to recognize broken IOPSP code that needs to be reworked, and thought of giving you a list of members that should not be used, ever.

The worst offending System. SerialPort members , ones that not only should not be used but are signs of a deep code smell and the need to rearchitect all IOPSP usage:. And the one member that no one uses because MSDN gives no example, but is absolutely essential to your sanity:. The only serial port read approaches that work correctly are accessed via BaseStream.

Its implementation, the System. Yes, the BytesToRead version can be adjusted to handle partial reads and bytes that arrive between inspecting BytesToRead and calling Read , but those are only the most obvious problems. Starting in. NET 4. Calling the Win32 API directly we would be able to streamline this even more, for example by reusing a kernel event handle instead of creating a new one for each block. With many. NET developers moving from the traditional and broken System. EndRead pair I promoted in my last post or the newer BaseStream.

ReadAsync Read more. National Pipe Thread Taper or NPT threaded pipes and fittings are deployed in a variety of fields where transportation or containment of liquids, gases, steam, or hydraulic fluid is required. The NPT geometry allows internal Read more.

Backing up important data and memories is an important task that should not be neglected. Just as important as performing Linux backups is verifying that the backups made are good and can be used to Read more. While it was a great starting point, there were a number of things that I wanted to change. If the project Read more. In a previous post I explained how you could configure the security DVR software Zoneminder to trigger recordings from a network connection.

While a neat trick, I never really explained why I set this up. Read more. Ports functionality. I tried using the built in handshake functions and my own to no avail. I am now using the Marshall software libraries that uses the API. Bob, are you using a publicly available software library for wrapping the Win32 serial port API?

Marshal class? I eventually stumbled on this post by reading many of your answers on StackOverflow. Rolling my own WinAPI wrapper would probably take me too long given my limited experience so I am quite interested to learn more on your take on this approach!

Ben, I am currently in the process of porting a VB6 serial port app to. NET and have found the performance to be inadequate. The app sends a series of messages with responses, before posting the next message. The intermessage gap is several milliseconds larger for the. NET version.

I am curious if I will see better performance using BaseStream ReadAsync but not exactly clear on how to handle new data arriving as efficiently as possible. Reading from the BaseStream will get the data to your application with low overhead. Could you expand upon line 8 in the recommended approach? At a high level it is a similar concept to the DataReceived event because it allows the application to respond to incoming data in an event-driven fashion.

Important differences are that the event actually carries the received data with it, so the application is all set for processing serial data, and the implementation does this with a single API call, which is far lower overhead.

Could you add more context? I get a compile error on line use of unassigned local variable. Net 4. Thanks Ben for all the explanation. I do not seem to find a good document on how to use it. Can You give full example on sending a message and receiving a response using BaseStream. I have tried this but it is not working for me? Sample would be very helpful. ReadAsync buffer , read, 7 — read ;. Unfortunately I have to use. If you ask a question on StackOverflow you are welcome to bring it to my attention here.

This is a much better approach than querying the buffer size. In general, just getting the data is more efficient and involves fewer race conditions than asking questions about the data and then retrieving it. Even creating a manual timeout and setting a condition would not work since await operator is sitting there to get more data, although reading task is complete.

You can avoid bad assumptions by either testing, or inspecting the implementation logic JetBrains dotPeek and Red Gate. NET Reflector are good options here. It seems like you did neither. The only way the. NET wrapper would not finish on timeout is if it detected a partial read and looped to read the rest. But I used dotPeek to verify that there is no such logic. A timeout will cause the ReadFile operation to complete, which means SerialStream. EndRead is called, and Stream.

Now, it is true that SerialStream. NET compact framework? NET Compact Framework does not support the asynchronous model with base streams. Any thoughts? Thanks for this posting! Is there anything special you want to note about writing to a serial port?

Exception: when the port is only emulating asynchronous serial and baud rate is meaningless In practice usually writes are interspersed with reading responses, and the write buffer never overflows. Are you still going to post those details and implementation?

Jason, yes those are still planned, but my dissertation committee asked for some edits before publication so those are a higher priority for my writing bandwidth this month. More serial port blog posts in March. I suggest you ask a question on StackOverflow, providing all the relevant details including some code snippets and the order of calls. Cancellation of overlapped or async operations may play into your issue as well.

Interesting point. SerialStream the class implementing BaseStream has these, but they are inaccessible. In the end though, it is a moot point. The SerialPort class appears to make these operations available, but actually makes them useless. Correct usage is to cancel your background operations, empty the buffers, and start them up again. So throwing away the wrapper classes and using the Win32 API possibly through a better wrapper looks like the only option, if your application really really needs these operations.

Also, what do I need to consider when closing the port? Maybe passing a CancellationToken to the ReadAsync method? So, maybe in a month, and you certainly should see more of my posts this summer. Any thoughts on this subject? Is there a way to write a windows library.

I did wonder if I could avoid the timeouts by waiting until there is actually data at the port e. Use the serial port the way it was designed. Is it possible to invoke java code from. If yes, take a look at this new open source library github. This post specifically addresses the case where developers are locked into the framework SerialPort class. When using other libraries is allowed, there are much better options than paying the.

NET Java integration cost. One does not simply upload code without scrubbing all mention of customer-specific requirements and defect reports from the comments. There are other 3rd party components as well. Probably am forgetting bits about it. Dmitry just ran into another example. Thank you for the article! It was really great to find it. And I really appreciate your explanation. Context: I have 1Mb one directional stream of data from a device to PC. Chunks are copied for several times, so it is possible to recover if one is lost.

Frame error happens from time to time. Frame error usually means that some data is physically lost. But for me it is essential to get as much possible around it. If I continue and call BeginRead after this, would I receive data from the first byte port recovered from Frame error? BytesToRead and BytesToWrite clear the status without reading it — obviously a very bad thing if you use them. As far as BaseStream. Sample code is useful for bypassing the missing DataReceivedEvent functionality in Mono.

Thank you Ben for tip of what to avoid and what to use. Before I was using Thread. GetString buffer. ReadAsync buffer, 0, int buffer. I plan to implement some sort of timeout if the loop runs x number of times then we can say something is wrong.

What do you think and do you have any suggestion? I would not ignore the return value from ReadAsync , which tells you how many bytes were actually placed into the buffer. Cheers for the quick response.

Sleep between the write and read to get the full answer, otherwise I receive strange results from the electronic device. Sleep feels like a hack for some reason, since I probably need to experiment with what Sleep time is necessary each time I connect a new device.

I also noticed if I send the same message several times Port. Thing is, even when I get wrong result, it still shows that the correct number of bytes have been received. A synchronous write will complete when the data is transferred to the kernel buffer anyway, without waiting for the serial transmission.

Be careful to set your encoding and the NewLine property. So in your approach you are not using the DataReceived handler at all and just running kickoffRead in a loop indefinitely? SerialPort and there seems to be a delay in the send. An external device tells me to do something.

It takes my program about 15ms to process this request and send the result back to the host. The host is timing me to see how long it takes. What external force is causing this delay? WOW — I have been struggling with Com time out errors and this seems the issue. I have also been trying to read serial data from a Tinsy serial device that work fine in tera tem but never fires the. Data recieved event handler. I will try you code above.. Thanks Very much…. DataReceived brokenness is race conditions, extra delays, things like that.

Using BaseStream. Serialport works as expected. Use datareceived to populate a concurrent queue along with a background task to read the queue. Works beautifully. I just spent forever trying to get a serial communication to work. The function here did not help either. Turned out that I have to set port. I have no idea why I have to do this manually.

Well, you do have to know the serial port settings required by the device you are trying to talk with. Baud rate, parity, stop bits… and in your case the critical piece you were missing is flow control handshaking. Do you know a good guide that covers these things? None of the ones I read mentioned such aspects.

I assumed I covered the handshake by setting the port. They all work and work robustly. The only thing that is tricky is that the port event runs on a different thread than the main program.

But, if you are a decent programmer, you can deal with that. One thing I forgot to mention is that Framework 2 and 3. Win 8. I feel sorry for your customers who try to use your devices on computers that are doing other things at the same time.

In my version, the error events should work. NET ones are delivered out of order , the software should achieve the full speed of the serial port making it likely that data continues arriving during your event processing , the software should work on a variety of different computers and even when CPU starved.

It should have a pit of success and just work, getting out of your way so that you can focus your mental energy on the specific features and logic of your application.

I guess when your software has controlled scientific instruments and robotics and has successfully captured in excess of 35 million data points worldwide by thousands of users with some of the most awful computers while people are looking at YouTube and listening to Internet music with absolutely no issues, that is my definition of robustness.

I guess if that you are basing your lamenting comments on your experience, you should probably learn how to create professional programs and not blame the technology. If you control the device firmware, you can work around any number of problems in the desktop code… but not efficiently.

Please, I have more samples in a single data set. Often in communication with devices over which I have no control, so implementing retries in the application protocol is not possible. So, continue to take your chances.

Trust me, we are an FDA regulated global manufacturer. If the issues you describe were true, all regulatory Hell would break loose. As I look at your code, I can see why you have issues. There are at least two glaring issues with it. Rather than attacking me, I would suggest that your time would be better spent thinking about your proposed solution and fixing it. That would have value for your users. That said, am I supposed to believe that you googled it and that is your support?

Are you kidding? NET in an application that the guidance applies to. Perhaps in your test and calibration software. If you had tried to use it in a regulated device, you would have had to perform a risk analysis and code review.

Just as I found issues by reading the code, you would have as well. Again, I will remind you what you already know — you cannot test quality into a multi-threaded application. Testing is not reliable for detecting the presence of race conditions.

SerialPort class and helper code supporting it, is suitable for FDA regulated software. NET in general, are completely unsuited for use in any life support system, or medical data system that presents data to be used for making medical decisions. You need code analysis. So just come out and admit it — the products you have using. NET are neither medical devices nor medical device data systems, and are exempt from regulatory processes.

Not only my company, but many other FDA regulated companies use it. Abbott, GE Healthcare, and Roche to name three. I learned how to program In and have been working in a GMP environment since That said, your guess at how things are actually validated, documented, and released are totally wrong.

Yes, I do suggest that you quit commenting now, because if you continue without clarifying what class of device you use. Nice article — certainly forced me to look at things again! I have an application using the DataReceived event on the SerialPort class to buffer data before validating the response and sending the next command no flow control!!

Ben is probably quite busy. I need to read 14 bytes secuentialy an when i achieve these bytes, send to event to add to a series as datapoint, i dont know how to use your code in my case. I know Ben is very busy but I was hoping that someone within the community may have a working example of how to use this approach within a C. NET 4 environment or. Without missing any data from packet sizes up to 65, COM port data logging FREE Serial Port Monitor has a simple interface, so to begin serial logging, you just need to select a serial port, choose where to file serial communication data, define RS port's parameters and click "Start".

Such functionality can be successfully used for testing. Our serial port logger is great for learning purposes, too. Collecting serial data in real time When you attach COM-based devices, like scales, meters, barcode scanners, etc. Analyzing COM port data If a COM port you want to monitor is already opened by a third-party application, Serial Port Analyzer will still be able to connect to it and record its activity.

Serial Analyzer software will let you select whether to show serial data in the Table, Line, Dump or Terminal mode. Also, you can enable all available visualizers at a time. Data viewing modes With the Table view, you get the data in the form of a table consisting of the recorded IRPs. When you select the Line view, you will see more details about each request passing in and out of a monitored COM port.

The Dump view will display all incoming and outgoing data in hexadecimal and string formats as a data dump. Also, you can save your monitoring session and load it next time you need it. All data will be recorded using the first-in, first-out method, which makes it more convenient for analysis. Sending commands via a terminal With RS monitor software, you can not only log serial traffic but also emulate sending data to a particular serial port as though it were sent from the monitored app.

This enables you to easily check how a device connected to this port reacts to specific data. Feature list comparison Check out the main differences in feature packs of free open source and advanced versions. Show 6 more features. Frequently asked questions about Serial Port Monitor. The needed settings were open and it was not complicated to get in closer touch with the different opportunities. Read More. Rating: 5. Shared Serial Ports Get simultaneous access to serial device by multiple applications in different ways View Details Download.