Text preview for : TEK-222_RS232_Interfacing_Guide_070-7533-00.pdf part of Tektronix 222 TEK-222 RS232 Interfacing Guide 070-7533-00



Back to : TEK-222_RS232_Interfacing | Home

Qservice ----- This Document is a complete scan from the Original Tektronix Manual ----- Qservice
CONTENTS
Page
HOST COMMUNICATION . . . . . . . . . . . . . . . . . . . . 1
RS-232 INTERFACE SPECIFICATIONS . . . . . . 1
RS-232 Communications Parameters . . . . . . . . . . . . 1
Baud Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Maximum Applied Voltage (any pin) . . . . . . . . . . . . . . 2
PlotterIPrinter Support . . . . . . . . . . . . . . . . . . . . . . . . . 2
Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
RS-232 OPTIONAL ACCESSORIES . . . . . . . . . . 2
CODES and FORMATS . . . . . . . . . . . . . . . . . . . . . . . 2
Commands. Queries. and Responses . . . . . . . . . . . . 3
COMMANDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
QUERIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
RESPONSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Logical Front Panel Encoding . . . . . . . . . . . . . . . . . . 11
VERTICAL SETTINGS . . . . . . . . . . . . . . . . . . . . . 11
SECIDIV SETTINGS . . . . . . . . . . . . . . . . . . . . . . 14
TRIG POS. SLOPE. SOURCE. AND MODE
SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
ACQUISITION MODE AND MlSC SETTINGS . . 18
RS-232 ERROR CODES . . . . . . . . . . . . . . . . . . . . . 20
Communication Error Codes . . . . . . . . . . . . . . . . . . . 20
Diagnostic Error Codes . . . . . . . . . . . . . . . . . . . . . . . 20
Error Code Decoding Examples . . . . . . . . . . . . . . . . 23
RS-232 COMMUNICATIONS . . . . . . . . . . . . . . . . 24
Waveform Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Software Tools . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Available Software . . . . . . . . . . . . . . . . . . . . . . . 24
Transfer to a Local PC . . . . . . . . . . . . . . . . . . . . 25
Transfer via a Modem . . . . . . . . . . . . . . . . . . . . 25
RS-232 Interconnection Cables . . . . . . . . . . . . . . . . 28
INDEX
222 RS-232 Interface Guide



RS-232 INTERFACE
HOST COMMUNICATION
Communication between the 222 and an external host computer is
provided via an RS-232 communications interface. The actual format
of the commands is as close to the Tek Codes and Formats as
possible with the limited memory space available. Certain functions
are compressed into a more compact form.
Waveforms and front-panel settings may be transferred over the
RS-232 serial port in ascii character strings. The optional RS-232
Demonstration Disk accessory (available by request only) supports
communications with an IBM8 PC AT@or PC compatible computer.
Operating details are provided on the disk in a "README" file.
A simple terminal can be used to receive the messages that may be
generated at power on or during self calibration if an error occurs. The
error codes are defined later in this manual. An RS-232
interconnection cable for use with the 222 is available as an optional
accessory. Setting the communication baud rate for the 222 is done
using menu selections available in the Auxiliary Functions menu
under CONFIG.

RS-232 INTERFACE SPECIFICATIONS
RS-232 Communication Parameters
Start bits 1
Stop bits 1
Data bits 8
Parity None
Flow Control XONIXOFF
Signals RX, TX, and SGND are functional. SGND is
connected internally to EXT TRIG COMM. DSR
and CTS are always high, and DTR and RTS are
ignored.
Baud Rates
300,1200,2400,9600; 0.1 % accuracy based on the
microprocessor clock.

IBM PC XT and IBM PC AT are registered trademarks of the International
Business Machine Corp.
222 RS-232 Interface Guide


Levels
Compatible with RS-232C.
Maximum Applied Voltage (any pin)
25 V (dc +
peak ac).
PlotterJPrinterSupport
There is no plotter support in the instrument.
Messages
User message displays on the instrument crt are not supported.
The controlling PC cannot send messages to be displayed for the
operator of the 222.

RS-232 OPTIONAL ACCESSORlES
RS-232 Demo Disk 063-0070-00
RS-232 Interconnection Cable 175-1453-00

CODES AND FORMATS
Commands, front panel setups, and waveforms sent over the RS-232
interface are composed of ascii character strings. The ascii
characters represent hexadecimal numbers, with two characters per
hexadecimal value. (See "Logical Front Panel Encoding" for the
meanings of the numbers.)
The general command format is as follows:
cmd arg:data;
where cmd is the command; arg is an argument to the command, and
data is any additional data needed for the command. A single white
space (either a space or a tab) is needed between the command and
argument. There must be no white space on either side of the colon
delimiter between the argument and the data. The semicolon is the
command terminator, but a carriage return also terminates the
command.
NOTE
The command is executed as soon as the command
terminator is received; multiple commands in a string are
executed at the command terminator as they are received. A
command can be aborted after it has started execution by
sending an ESCAPE character.
222 RS-232 Interface Guide



Commands, Queries, and Responses



I COMMANDS 1 I
QUERIES RESPONSES
CURV CURV?
BUT ID?
DAC TRG?
FP STA? READY
DAC? DAC
FP? FP XXX;
CAL? CAL



Figure 1. Commands, Queries, and Responses.

The set of commands and queries sent to the instrument and the
responses sent by the instrument are shown in Figure 1. Explanation
for each is given in the following text.

COMMANDS. The following commands are supported:

CURV :
< wfrm data > Loads waveform data into the
specified 222 reference memory
(REF1 -REF4). The wfrm data must
be sent as hex-encoded ascii
characters.
Note

Waveformsmay be written back to Channel I and Channel 2,
but they will be overwritten by the next acquisitions into those
memories.
222 RS-232 Interface Guide



is one of the following strings:
CH 1 Channel 1 waveform
CH 2 Channel 2 waveform
REF1 Reference waveform 1
REF2 Reference waveform 2
REF3 Reference waveform 3
REF4 Reference waveform 4

< wfrm data > is composed of nr > < byte count > data > < checksum > , defined as
follows:
c fp data > Ten ascii characters representing
hexadecimal bytes of the front panel
settings for the waveform data. See
"Logical Front Panel Encoding" for the
meaning of the characters.
c frame nr > Two ascii character representing the
frame number (in hexadecimal) the
curve data is taken from. The frame
numbers range from 00 for the RO
(readout) frame to 06 for the REF4
(reference waveform 4 frame).
< byte count > Four ascii characters representing the
data byte count for the waveform data
(in hexadecimal).
In YT mode, each data point is
the hexadecimal value (represented
by two ascii characters) of the
Y-coordinate.
In XY mode, the X- and
Y-coordinates are sent as two
hexadecimal values (represented by
four ascii characters) with the
X-coordinate value first, followed by
the Y-coordinate value.
222 RS-232 Interface Guide



< checksum > Two ascii characters representing the
hexadecimal twos complement of the
modulo 256 checksum of all data
bytes and the byte count bytes.
Note

Programmers take note, additional bytes may be added to
the data string after the checksum byte. This space is
reserved for future expansion.
BUT < button > Simulates a button press.