B&K Precision 5491B - Manual - Manual (Page 41)

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Chapter 5 Remote Operation
Besides the front panel control, the multimeter provides a USB interface and RS232 interface (model
5491B only) for remote control. Standard Commands for Programmable Instruments (SCPI) is fully
supported to communicate with computer via the serial interface.
5.1 USB & RS232
You can connect the USB interface or RS232 interface (Model 5491B only) to a computer. To do so,
please note the following:
 You must define the baud rate, parity, start bit, and stop bit (the USB interface is a virtual COM,
therefore it behaves like a RS232 serial port). Settings automatically will apply for RS232 port
also.
 You must use the SCPI programming language
5.2 Serial Interface Operation
The instrument provides various remote commands. All operations from the front panel can be
performed by a computer via the USB interface.
5.2.1 USB interface configured as virtual COM RS232 interface
The USB interface in the rear panel of the instrument is a virtual COM port and behaves like a RS232
interface. This means that it can be connected to a USB port on a PC, and with the USB drivers
installed the PC will detect it as a serial COM port just like a RS232 serial port. In Windows, the PC will
automatically assign a COM port to the USB connection upon successful USB driver installation. Use
this COM port and configure the Baudrate, Parity, Start bit, and Stop bit settings as you would for RS232
communication. The settings will also apply to the RS232 port on model 5491B.
5.2.2 Sending and receiving data
The multimeter transfers data using 8 data bits, 1 stop bit, and no parity. Each program message that is
transmitted to the controller is terminated with or . Refer to section 4.5.3 for details on
configuring the termination character setting.
5.2.3 Selecting Baud Rate
The baud rate is the rate at which the multimeter and the computer communicate. Choose one of these
available rates:
 38.4k
 19.2k
 9600
 4800
 2400
 1200