Is It Possible to Get a Constant Signal Out of a Serial Port? Primary Software: Driver Software>>NI-VISAPrimary Software Version: 3.5.1 Primary Software Fixed Version: N/A Secondary Software: Driver Software>>NI-Serial Hardware: Serial
Problem: I need to use a serial port to output a 5 volt signal indefinitely. Can this be done? Solution: Although it is not a common application to output voltage from a serial port it can be accomplished. You can think of a serial port as in/out port, with 3 output lines (TxD, DTR, RTS) and 4 input lines (CTS, DSR, DCD, RI). Output Lines: TxD (pin 3): Serial data output DTR (pin 4): Data Terminal Ready RTS (pin 7): Request to send Input Lines: CTS (pin 8): Clear to send DSR (pin 6): Data Set Ready DCD (pin 1): Data Carrier Detect RI (pin 9): Ring Indicator also RxD (pin 2): Serial data input These can be controlled and used as constant voltage outputs using a VISA property node set to Serial Settings >> Modem Line Settings. As an example you could send a break command continuously to output a constant 5 volts. An example, created in LabVIEW 8.2, is attached below. Related Links: KnowledgeBase 21P954LI: How Can I Control the DTR and RTS Serial Lines in LabVIEW? KnowledgeBase 1M9E1L6Q: Serial Communication General Concepts Attachments:
Report Date: 08/25/2006 Last Updated: 09/28/2006 Document ID: 40OECPA0 |
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