8
To commence plotting press PLOT (key 6). The oscilloscope dis-
play will show a series of prompts for setting the plotter. If RUN /
HOLD is at RUN it will be set to HOLD. To abandon plotting
before it is completed press ESCAPE.
A more complete description of the analog plotter PLOT function
is given in Appendix D.
R23. PRINT
The waveforms shown on the oscilloscope display can be con-
verted to hard-copy using a dot-matrix printer. The printer must
be compatible with EPSON graphics commands (including quad
density bit mapping) and must be fitted with a serial interface for
connection to the RS-423 interface socket of the DSA. For details
of making connections and of setting the baud rate see Section
R25. Baud rates below 2400 are not recommended as the
printing time becomes excessive.
The waveforms are printed with an 8x10 graticule using the same
1:1 aspect ratio as the oscilloscope display. They are preceded by
several lines of text which detail the present settings of the DSA.
Line feeds are arranged so that two prints will fit onto one sheet
of 11 inch paper.
To commence printing, press SHIFT (key 8) followed by PRINT
(key 6). RUN /HOLD will be set to HOLD and printing will com-
mence. To abandon printing before it is completed press ESCAPE.
R24. REMOTE CONTROL AND DIGITAL DATA TRANSFER
The DSA can be fully controlled via its RS-423 serial interface or
its IEEE-488 interface (if fitted). Anything that can be controlled
from the front panel can also be controlled via these digital inter-
faces. Waveform data can be sent to and from the DSA using the
interfaces, and a variety of other functions are also available.
The software commands for use on either of these interfaces are
listed in Appendix F. ‘Software Commands’.
R25. RS-423 INTERFACE
The DSA524 is fitted with an RS-423 serial interface which is fully
compatible with equipment fitted with an RS-232C interface. It
can be used for remote control of the DSA, for bidirectional data
transfers and for connection to a printer or a digital plotter.
The RS-423 interface is connected via the 9 pin female D
connector mounted on the rear panel. The connections are as
follows:
Pin No. Name Function
2 RXD Input line for sending data to the DSA
3 TXD Output line for sending data from the DSA
5 GND Signal ground line
7 RTS Output line for handshaking (Request to
Send)
8 CTS Input line for handshaking (Clear to Send)
The interface operates with 8 data bits, 1 start bit, 1 or more
stop bits, no parity. If hardware handshaking is not being used,
pin 8 (CTS) must be pulled permanently high, this can be done
by linking it to pin 7 (RTS) and forcing RTS permanently high by
using function 83 (see Section R27). X-on/X-off handshaking can
be used as an alternative to hardware handshaking.
The baud rate is adjustable in binary steps between 300 baud
and 38,400 baud. Once set, the baud rate is stored in non-
volatile memory and will remain set. As shipped from the factory
it is set to 9,600 baud.
To change the baud rate press SHIFT (key 8) followed by SET
BAUD (key 3). The display will show "baud rate = 9600" (for
example). Use the reference cursor keys (keys 2 and 3) to
increase or decrease the rate, then press ESCAPE. If the DSA is
not connected to an oscilloscope the baud rate may be set
directly using the FUNCTION NN key (see Section R27).
Note that as well as the options of 300 through to 38,400 there is
a further option of IEEE. This option is exclusively for use when
the optional IEEE-488 interface board is installed and enabled.
Note that the RS-423 interface cannot be used when the IEEE-
488 interface is enabled.
Further details of making connections to the RS-423 interface
are given in Appendix E.
A description of the software commands for remote control and
data transfer via the interface is given in Appendix F.
R26. GP-IB (IEEE-488) INTERFACE
An optional module is available which interfaces the DSA524 to
the General Purpose Interface Bus (GP-IB) using the IEEE-488
standard. This option makes all of the functions which are avail-
able via the RS-423 interface also available via the GP-IB inter-
face. The interface can be used either with a controller or with-
out a controller in "talker only" mode for connection to a printer
or digital plotter.
A full description of the fitting and operation of the GP-IB inter-
face module is provided in the separate manual supplied with it.
A description of the software commands for remote control and
data transfer via the interface is given in Appendix F. ‘Software
Commands’.
R27. DIRECTLY ACTING FUNCTIONS
Some of the parameters of the DSA which are normally set
interactively using the text readout on the oscilloscope display
can also be set directly using the FUNCTION NN key. These
include setting the baud rate for the RS-423 interface and
setting the analog plotter rate.
A full list of these functions is given below:
Set Analog Plotter Rate 1sec /div 21
2sec/div 22
5sec/div 23
10sec/div 24
Select Analog Plotter Routine auto version 25
Select Analog Plotter Routine prompted version 26
Select Digital Plotter Routine 27
Set Baud Rate 300 30
600 31
1200 32
2400 33
4800 34
9600 35
19200 36
38400 37
IEEE-488 mode 38
Turn bandwidth limiting off 80
Turn bandwidth limiting on (factory default) 81
(a bandwidth limit of about 6MHz is applied
except in repeat mode)
Enable hardware handshaking via RTS (factory default) 82
Disable hardware handshaking via RTS 83
(disabling RTS handshaking forces RTS permanently high)
Note that the RESET function cancels the effect of Function 80.
The following functions are intended for use by Service Engin-
eers only (in conjunction with the appropriate service manuals):
Start analog plotter calibration routine 20
Check display lamps 70
Check keyboard switches 71
Check rotary controls 72
Check DAC output waveform 73
Check RS-423 operation 74
Check Autocal values 75
Return bytes from RS-423 input buffer 76
Clear all set-up parameters 78
Function 78 can be used if the DSA appears to have suffered a
program corruption from which it cannot be made to recover
either by switching the DSA off or by using the RESET function.
Note that the contents of all the memories including the
indexed waveform stores and the PROGRAM memory will be
cleared. Function 78 restores the DSA to the same state as
when it left the factory.
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