![]() A termination character is generally a non-printing character that signals the end of the data. Dim sfc As VisaComLib.ISerialįor some instruments a termination character is required for reading and writing data. Use this interface to set the RS232 parameters. Using RS232 requires you to use the Serial Interface, ISerial, built in the VISA COM libraries. Notice how the interface family for RS232 is ASRL. Set instrument.IO = mgr.Open("ASRL1::INSTR") Set instrument = New VisaComLib.FormattedIO488 ![]() Dim mgr As KeysightRMLib.SRMClsĭim instrument As VisaComLib.FormattedIO488 Set mgr = New KeysightRMLib.SRMCls First, connect to the instrument similarly to connecting to an instrument using GPIB, LAN or USB interfaces. You can write Visual Basic code that can set RS232 parameters for you. None (no handshake mode), DTR/ DSR, Modem, RTS/ CTS, XON/ XOFF None / 8 data bits, Even / 7 data bits, Odd / 7 data bits Refer to the instrument's documentation to determine settings for the following parameters. Older instruments often have a fixed set of parameters. Newer instruments often allow you to set parameters, typically through the front panel. In general, the instrument will be the limiting factor for parameter setting. This is the cable shipped with many Keysight instruments that support RS232.īoth the PC and the instrument must be set to use the same configuration for serial communications. The diagram on the right is a simpler cable. This pin out will work with most Keysight and non-Keysight instruments. The pin out on the left for a printer cable. A typical instrument to PC cable pin diagram is shown on the right. If the manual is unavailable, try one of the two cables shown below. The Keysight 34398A Cable Kit contains cables and an adapter to help you connect serial interfaces.Ĭheck your instrument manual for the proper cable to use. Typical adapters include gender changers, null-modem adapters, and "D" style adapters with 9 pins or 25 pins. If you are using a DTE-to-DTE cable, make sure the adapter is a "straight-through" type. If you cannot find the correct cable for your configuration, you may use a wiring adapter. The Keysight 34398A serial cable with a 9-pin female connectors will work with these instruments. Most Keysight instruments use a 9-pin configuration. A male connector has pins inside the connector shell and a female connector has holes inside the connector shell. Connectors are typically a "D" style with 9 pins or 25 pins (DB-25 connector) with a "male" or "female" pin configuration. The interface cable must also have the proper connector on each end and the internal wiring must be correct. These cables are also called null-modem, modem-eliminator, or crossover cables. To connect these, you must use a DTE-to-DTE interface cable. Most computers are DTE (Data Terminal Equipment) devices. To connect the instrument to a computer, you must have the proper interface cable. ![]() Finally, set and verify the RS-232 communication parameters. To use the RS-232 interface make sure it is enabled (selected) and determine the proper cables to connect the computer to the instrument. The UBRRH contains the four most significant bits, and UBRRL contains the 8 least significant bits of the USART baud rate.When it comes to interfaces RS-232 is pretty inexpensive to incorporate and over the years many instruments have been designed with an RS-232 interface. This is a 12 bit register which contains the USART baud rate. ♦ Bit 11:0 - UBRR11:0: USART Baud Rate Register The URSEL must be one when writing the UCSRC. The UCSZ1:0 bits combined with the UCSZ2 bit in UCSRC sets the number of data bits ( Character Size) in a frame the Receiver and Transmitter use. Writing this bit to one enables the USART Transmitter. Writing this bit to one enables the USART Receiver. Well it's dig a little deeper in the init function to see how it is set up. Well, this looks cool isn't it? Just a one include uart.h and one UART_init(9600) function. UART_Printf ( "Welcome to AVR Serial Programming by ExploreEmbedded \n \r" ) } return ( 0 ) } ![]()
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