User manual

30
Subject to change without notice
Interface settings
This menu item is used for the settings of the diverse inter-
faces:
1. The dual interface HO720 USB/RS-232 (Baud rate, num-
ber of stop bits, parity, handshake on/off).
2. LAN interface HO730 (IP address, sub net mask etc., see
the HO730 manual).
3. IEEE-488 GPIB interface HO740 (GPIB address).
STORE/RECALL
The actual instrument settings can be stored in the memory
locations 1 to 9. By pushing the knob
10
the pertinent selection
line can be accessed. The knob is used for the selection of the
location 1 to 9, the selection is confi rmed by pushing the knob.
RECALL allows to recall the settings. It is possible to also store
a date.
6 Control of the signal output
The key OUTPUT
11
is used to
turn the output on or off at any
time. Prior to turning the output
on, all parameters can be set
comfortably. If the output is ac-
tivated, the white LED of the key
will light up.
A positive or negative DC offset
may be added to the output signal. If an offset was selected it will
be added by pushing the key OFFSET
12
which will light up.
Fig. 6.2: Explanation for offset function
The diagram shows two signals. The lower curve without offset
is referenced to ground with an amplitude of 10 V
pp
. The limits
of the output stage are shown from –10 V to +10 V which equals
20 V
pp
. The second upper curve has an offset of +5 V, it reaches
the upper limit of +10 V, hence it is not possible to increase the
offset further, e.g. to +6 V. The amplitude will then be automa-
tically decreased. The signal amplitude can not be increased if
the offset is already +5 V as this would also violate the limit.
STOP
If the offset is decreased to +4 V, the amplitude can
be increased to 12 V
pp
.
The output signal polarity can be inverted by pushing the key
INVERT
13
which will light up white.
STOP
Any offset will be also be affected by a signal
inversion. Inversion is only possible for the wave-
form pulse which is the only one not symmetrical to
ground.
As mentioned the maximum output voltage including an offset
can not be increased beyond 20 V
pp
open circuit. Hence, for an
amplitude of 8 V
pp
e.g. the maximum offset possible is 6 V. Within
this range the offset voltage can be varied continuously from
negative to positive values. The same conditions are valid if the
sweep function is used with offset.
Control of the signal output
Fig. 6.1:
Controls for
output, offset
and invert
function