VISA-serial Communication Parameters

You should configure the VISA-serial object to match your instrument's communication configuration, which you typically set through its front panel.

• Select an Adaptor
• Port
• BaudRate
• DataBits
• StopBits
• Parity
• FlowControl
• Terminator

Select an Adaptor

You can create a VISA-serial object that uses the VISA standard as implemented by Agilent Technologies, National Instruments, or Tektronix.

Port

Select the port to associate with the VISA-serial object and the instrument.

BaudRate

Select the baud rate of the VISA-serial object.

DataBits

Select the number of data bits used to transfer data to and from the instrument. At least seven data bits are required to transfer ASCII characters. Eight data bits are required to transfer binary data. Five and six bit data formats are used for specialized communications equipment.

StopBits

Select the number of bits used to indicate the end of data transmission.

• 1 - One stop bit is used.
• 2 - Two stop bits are used.

Parity

Select the type of parity checking.

• None - Parity checking is not used.
• Even - The number of mark bits (1's) in the data is counted, and the parity bit is asserted or unasserted to obtain an even number of mark bits.
• Odd - The number of mark bits in the data is counted, and the parity bit is asserted or unasserted to obtain an odd number of mark bits.
• Mark - The parity bit is asserted.
• Space - The parity bit is unasserted.

Parity checking can detect errors of only one bit.

FlowControl

Select the data flow control (handshaking) method.

• None - Data flow control is not used.
• Hardware - Hardware handshaking is used.
• Software - Software handshaking is used.

Hardware handshaking typically utilizes the Request to Send (RTS) and Clear to Send (CTS) pins to control data flow. Software handshaking uses control characters (Xon and Xoff) to control data flow.

Terminator

You can configure Terminator to an integer value ranging from 0 to 127, to the equivalent ASCII character, or to empty (''). Some common terminators include:

• 'CR' or 13 - A carriage return is used.
• 'LF' or 10 - A line feed is used.

Additionally, you can set Terminator to a 1-by-2 cell array. The first element of the cell is the read terminator and the second element of the cell array is the write terminator.

When performing a formatted write operation, all occurrences of \n are replaced with the terminator. When performing a formatted read operation, one of the ways the operation completes is when the terminator is read. You can also use the terminator to generate a bytes-available event when the BytesAvailableFcnMode parameter is set to terminator.