33
Operation of the HM8143
Example
: Modulation source V
mod
= 2,0 V
ss
f
mod
= 50 Hz
channel 1
V
set
=
1
0 V
channel 3
V
set
= 10 V
5.7 Tracking
With the aid of the tracking function, it is possible to simul-
taneously vary 2 setting parameters of the two 30 V-chan-
nels. In other words, either both output voltage settings or
both current limits can be varied at the same time by using
the tracking function. This function is activated by pressing
the TRACKING button
14
. The TRACKING LED is lit. To exit
the tracking mode, press the TRACKING button
14
again .
This has the effect of clearing all previously activated func-
tions, and from then on whenever a value is called and
changed both channels of the instrument are identically
affected (the 5 V output remains unchanged). It does not
matter which values had been set prior to changing one of
the parameters; in the tracking mode, the HM8143 always
retains the respective differences between the voltages va-
lues and the current limits, except if the minimum or ma-
ximum values of current limit (0.005 A or 2 A) or of the out-
put voltage (0 V or 30 V) is reached. In this case, the diffe-
rence of voltage or current will be reduced as long as it will
be zero. That means until the values of the output voltage
or current limit of both channels have set to the minimum
or maximum values.
0 V
1 V
2 V
modulations signal
10 V
13 V
16 V
0 V
3 V
6 V
channel II
channel I
If a modulation voltage of 2 Vpp is applied, the nominal value of
the output voltage of the HM8143 must not exceed 24.00 V.
5.8 Change of the display refresh rate
From firmware version 2.40 the display refresh rate of the
measured voltages and currents can be varied. The selec-
ted display rate is shown during boot procedure in the vol-
tage display of channel 2
11
.
L = Low display rate, i.e. the displayed value corresponds
to the average value from 8 measurements. Approx. 3 va-
lues per second are displayed.
H = High display rate, i.e. the measured values are shown
directly the display. Approx. 24 values per second Are
displayed.
To change the display refresh rate, hold the TRACKING
key
14
when switching on the instrument, until you hear 3
beeps. The display refresh rate is changed according to the
following pattern: L
H
L etc.
Please note that the data which are sent via remote control
(e.g. with command MI1) are transmitted according to the
display refresh rate.
If the ground of the modulations source is connec-
ted with the safety ground terminal , the modulation
source has to be operated via an isolation transfor-
mer, as there will be no electrical isolation of the po-
wer supply.
