Using Virtual COM Ports or Third-party USB-to-Serial Adapters with VISA in MAXHardware: Serial
Problem: I'm having trouble using my virtual COM port or third-party USB-to-serial adapter in Measurement & Automation Explorer(MAX). I keep getting VISA errors. What's wrong? Solution: Most virtual COM ports and many low cost USB-to-serial adapters do not fully comply with the serial specification and therefore do not support a lot of the functions that VISA uses, such as asynchronous I/O and flushing. If you make your own VISA calls (either through a VISA test panel in MAX or a development environment) and avoid any calls that aren't supported by the driver for your virtual COM port then it may work, but because each virtual COM port implements different functionality, they are not officially supported by MAX or VISA. Note: Another work around would be to try adding a token to the visaconf.ini file: WriteTimeoutGranularity = 0 under section [ASRL-RSRC-ALIAS].
Report Date: 07/13/2006 Last Updated: 11/05/2008 Document ID: 3ZC9A3DW |
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