Characters (Rs-232-C); Rs-232-C Terminators - Wavetek 75 Instruction Manual

MARK
OPTIONAL
START BIT PARITY
Figure 3-9. Transmission Example
SPACE
When the Model 75's internal buffer fills, it will do one
of two things depending on the handshaking mode set
from the HAND soft key. If the handshaking mode is
CTSIDTR, the Model 75 will set the CTS line negative if
it in the DCE configuration or set the DTR line negative
if it is in the DTE configuration. When the Model 75 is
again ready to receive data it will set the appropriate line
back positive. If the handshaking mode is set to
XONIXOFF, the Model 75 will send an XOFF character
over the data line. When it is again ready to receive data
it will send an XON. After the Model 75 either sets the
handshake line negative or sends the XOFF, the con-
nected device must stop sending data within 10
characters or data will be lost.
The SRQ mode (XQn) has no effect over the RS-2326
interface, however the serial poll byte can be read using
talk mode(XT1). The bitsof the serial poll byte aredefined
in the same way as over the IEEE-488 interface and all
bits are always enabled.
When the instrument is in the remote mode (sending the
character '!'causes the instrument togo to remote), the
RS-2326 interface input has priorityover any front panel
control, and the Control knob is completely ignored.
Therefore, as long as theserial interface is continuously
supplied with data, the keyboard will appear to be
inoperative to the user.
DATA BITS STOP BITS NEXT TRANSMISSION
4
*
P
Line 2 of the LCD always shows the siate of the serial
interface after scanning the last string. In the lower right
corner, a character will appear:
'R'
=
Remote (if the unit is in remote)
Line 1 is the parameter and special message readout.
An asterisk to the left of the parameter indicates that an
execute has not been sent.
The front panel display is externally programmed by
sending any ASCII character between single or double
quotes, such as 'test string' or "test string".
The Model 75 is programmed by sending ASCII coded
characters to the instrument (see table 3-2 and Appendix
A).
+
i
h
V
IDLE
- --
3.31.1 Characters
There are 6 types of characters that can be sent over
the RS-232C interface. These are:
m
5
Alphabetic characters; 'A' through 'Z' (except 'E'). These
select action or parameter commands. Both upper
and lower case characters are accepted.
m
( I I
5
Numeric characters (Suffix); These are '0' through '9',
'E' (exponent),
'
-
'
(negative),
'
+
'
(positive), and
the decimal point. They control the selected
parameter.
Special characters; The instrument will display any set
of characters within single quotes, such as 'string'.
Interface Control Characters; These are the characters
I ! ' , I * ' ,
'$',
I ? ' ,
'XON', and 'XOFF'.
Terminator; Designates the end of a character string.
Initially, the instrument will accept a 'CR' or a 'LF'
and send a 'CR
+
LF' as a terminator.
Nonprogramming characters; These are characters
not in one of the previous described classes. They
have no effect on programming and may be
interspersed freely after any programming
character other than 'X'.
3.31.2 RS-2324 Terminators
Upon "power-on", the Model 75 accepts either a
carriage return(CR)or a linefeed(LF)asan endof string
(EOS) terminator and sends both a CR and LF as the EOS
terminator. If the connected device does not recognize
either one, the terminator will need to be changed. The
terminator can be changed to any ASCII character other
than XON and XOFF, or NULL by sending 'XV' followed
by the decimal ASCII code for the character. A terminator
code of '0' is a special case and represents the default
condition of sending a CR and LF and accepting either
CR or LF as previously mentioned.
Scans by ArtekMedia O 2006