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OPERATION
Pressing CHANNEL
does two things:
1. It toggles the display between channel 1, channel 2, and
the dual-channel
display mode. Table 3-4 shows typical
displays for each of the three formats. For the two single-
channel formats, the channel number
appears in the
right most digit. In the dual channel display mode, chan-
nel 1 is on the left, and channel 2 is on the right.
2. It allows you to access a particular channel for program-
ming
remaining
parameters.
To change
channel
operating modes, the display must be in the single chan-
nel mode of that particular channel. For example, to pro-
gram the rate on channel
1, you must first use the
CHANNEL
button to display only that channel. Similar-
ly, if you wish to change the range on channel 2, you
must first display channel 2 by pressing CHANNEL
and
then use the appropriate
range button
to change the
range.
Table 3-4. Display Format
3.9.3 Speed Considerations
Each channel has its own A/D converter, 64K bytes of
memory, and clocking circuits. As a result, each channel
can be independently
programmed
for the maximum
@MHz) sampling rate without
affecting sampling rate of
the other channel. However, the overall reading rate will
be reduced if both channels are sampling simultaneously.
3.9.4 Cross Channel
Triggering
Either channel can be triggered by the other channel to
begin its measurement sequence. To do so, program each
channel
for the appropriate
trigger mode, as required.
Paragraph 3.6 covers triggering
in detail.
As an example, assume that channel 2 is to be triggered
by channel 1, and that channel 1 is to be triggered by a
positive-going
input signal at a threshold
of 4.6V.
1. Using the CHANNEL
button,
select the channel
2
display mode.
2. Press the SOURCE
button
and then
uprange
or
downrange
repeatedly
until the following
message is
displayed:
OTHER CHANNEL.
3. Press the CHANNEL
button, as required, to select the
channel 1 display mode.
4. Select input signal triggering
with the SOURCE and
uprangc keys.
5. Using the SLOPE button, program channel 1 to tripp
on the positive-going
edge.
6. Press the LEVEL button and key in a trigger level of
+4.6V. To do so, press: 4,
,6 , V.
7. Arm both channels by pressing TRIGGER in the dual-
channel display mode.
8. With this programming,
channel
~1 will be triggered
when the input signal rises above 4.6V. Channel 2 will
in turn be triggered by channel 7.
3.10 USING ZERO
The zero mode allows a stored offset value to be subtracted
from subsequent
readings. The stored offset can be ob-
tained from an applied signal, or directly keyed in \vith
the data entry keys. Once the baseline is stored, the zero
mode can be enabled or disabled by pressing the ZERO
button.
When the zero mode is enabled, the ZERO in-
dicator will be on.
ZERO KEYS
f
ZERO
>
When the instrument
is in the dua-channel
display mode,
the ZERO button and associated indicator are inoperative,
although
the instrument
will remain in the selected zen~
mode if already so programmed
when entering the dual-
channel
mode. The unit must be in a single-channel
display mode to change or indicate the mode presently in
effect.
The zeroed reading can be as small as the resolution
of
the instrument
(lOl,V), or as large as full range. Somr
typical examples include:
Zeroed Reading
Applied
Signal
-
D+ayed
Value
+10.5oov
+18.6OOV
1~8,lOOV
+2.566V
+1.8OOOV
-0.756OV
-12.6OOV
+4.5ooov
+'17.1oov
3-17
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