A time-critical loop, which does not have any sleep time, will completely monopolize the embedded CPU resources. The issue is that you must not starve the system of CPU time if you plan to have anything else going on, such as a user interface thread or TCP/IP communication. Time-Critical Priority gives 100% of the CPU time to the time-critical thread. So, the embedded CPU will share time with your LabVIEW Real-Time VI and with the user interface thread or any other threads you may have going. Normal Priority allows the CPU to be shared between threads. Refer to Fix Corrupt or Non-Working NI Software with Force Reinstall.In LabVIEW, events are prioritized, where events with higher priority execute first. You may need to repair these installations if the error continues and you have tried all of the steps above. This is unlikely, but to use serial devices you need to have LabVIEW, NI-Serial, and NI-VISA on your computer. Move the serial cable way from power cables, monitors, or other potential noise sources. You may be experiencing noise on your serial line. Refer to the article: Should I Use Null Modem or Straight Through Serial Cables?į. Try another serial cable and check your device manual to determine if a null modem or straight through cable is required. You may have a bad serial cable or the wrong type of serial cable. Check to make sure your cables are securely plugged in.Į. Note: You can change these settings programmatically during run-time as seen in the example above, or in NI-MAX as in the example below.ĭ. The easiest way to check the configuration is by tracing the received signal with an oscilloscope. Verify that the VISA Resource Name, Baud rate, Data bits, Parity, and Stop bits all match the settings of your device under the port settings tab. To solve this issue, open NI Measurement & Automation Explorer (NI MAX) and select your serial port under Devices and Interfaces. Your serial port and device may be configured to use different settings. You may be closing the VISA Resource before the Read/Write task is complete.Ĭ. Your block diagram should appear as shown below:ī. Reading after this sequence should work correctly.
Then, by using a VISA Flush I/O Buffer VI, you can clear any invalid data in the buffer. By putting a delay (approximately 10-100 ms) after the VISA Configure Serial Port VI, you allow the serial port enough time to configure itself. The port may not have completely finished its configuration by the time the first character is received off of that port. A framing error occurs when a byte of data is received, but it is not in the format expected. This kind of error may occur for several reasons:Ī.
Each byte has a specific format with a start bit, data bits, parity, and stop bits. Serial data is transferred one byte at a time.
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