B&K Precision 4034 - Manual - Manual (Page 69)

69
5D 135 93 MTA29 7D 175 125 } MSA29,PPD
5E 136 94 ^ MTA30 7E 176 126 ~ MSA30,PPD
5F 137 95 _ UNT 7F 177 127 DEL
Message Definitions
PPE
Parallel Poll Enable SPE Serial Poll Enable
PPU Parallel Poll Unconfigure TCT Take Control
SDC Selected Device Clear UNL Unlisten
SPD Serial Poll Disable UNT Untalk
4.16 RS-232 Programming
4.16.1 General
The INSTALLATION section of this manual describes the RS-232-C connection for the instrument. Be sure that
you have the Remote Mode set to RS-232 and correctly set the baud rate.
EIA standard RS-232-C specifies the electrical characteristics and pin out of a serial communication standard for
connecting "data terminal equipment" (DTE) to "data communication equipment" (DCE). Data terminal
equipment is usually devices such as terminals, computers, or printers that are the final destination for data. Data
communication equipment, on the other hand, is usually a modem or other device that converts the data to another
form and passes it through. The instrument can be configured only as a DCE, so in most cases it can be connected
with a straight-through cable to a computer, but would require special cabling to connect to another DCE device.
The baud rate is the bit rate during the transmission of a word in bits per second. Different devices use many baud
rates, but the baud rates of the two devices that are connected must be the same. The instrument can be set to
different baud rates ranging from 1200 to 115,000 as described in Section 3, Operating Instructions.
Data signals over the RS-232-C use a voltage of +3V to +25V to represent a zero (called a space) and a voltage of
-3V to -25V to represent a one (called a mark). Handshake and control lines use +3V to +25V to indicate a true
condition and -3V to -25V to indicate a false condition.
When no data is being transmitted, the idle state of the data lines will be the mark state. To transmit a byte, the
transmitting device first sends a start bit to synchronize the receiver.
4.16.2 RS-232-C Operation
The RS-232-C standard is not very specific about many of the handshaking signals and it is therefore usually
necessary to refer to the manuals for both of the devices being connected to determine the exact pin out, signal
definition, and signal direction for the devices.
The serial interface implements the same SCPI command set as the GPIB interface. The instrument is programmed
by sending ASCII coded characters to the instrument.
When the instrument is in the remote mode remote command input has priority over any front panel control.
Therefore, as long as the serial interface is continuously supplied with data, the keyboard will appear to be
inoperative to the user.