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Operation
2-29
3. If a trigger overrun occurs (the instrument is triggered
while processing a reading from a previous trigger), it
will ignore the trigger and display the following:
t Err
2.12.2 Meter complete output
The Model 6512 has an available output pulse that can be used
to trigger other instrumentation. A single TTL-compatible
negative-going pulse with a minimum duration of 10µsec (see
Figure 2-21) will appear at the METER COMPLETE OUT-
PUT jack each time the instrument completes a reading. To
use the METER COMPLETE OUTPUT, proceed as follows:
1. Connect the Model 6512 to the instrument to be triggered
with a suitable shielded cable. Use a standard BNC coax-
ial cable to make the connection to the Model 6512.
CAUTION
Do not exceed 30V RMS between the
METER COMPLETE common (outer
ring) and chassis ground, or instrument
damage may occur.
2. Select the desired function, range, trigger mode, and
other operating parameters, as desired.
3. In a continuous trigger mode, the instrument will output
pulses at the conversion rate; each pulse will occur after
the Model 6512 has completed a conversion (about ev-
ery 360msec).
4. In a one-shot trigger mode, the Model 6512 will output
a pulse once each time it is triggered after it completes
the reading conversion.
Figure 2-21
Meter complete pulse specifications
2.12.3 Triggering example
As an example of using both the external trigger input and
the meter complete output, assume that the Model 6512 is to
be used in conjunction with a Keithley Model 7001 Switch
System to allow the Model 6512 to measure a number of dif-
ferent signals, which are to be switched by the scanner. Us-
ing appropriate scanner cards, the Model 7001 can switch up
to 80 2-pole channels.
By connecting the triggering inputs of the two instruments
together, a complete automatic measurement sequence could
be performed. Data obtained from each measurement point
could be stored by the data store mode of the Model 6512.
Alternatively, the Model 6512 could be connected through
the IEEE-488 bus to a printer, which would print out the data
for each point as it is measured.
Once the Model 7001 is programmed for its scan sequence,
the measurement procedure is set to begin. When the Model
7001 closes the selected channel, it triggers the Model 6512
to take a reading. When the Model 6512 finishes the reading,
it triggers the Model 7001 to scan to the next channel. The
process repeats until all channels have been scanned.
To use the Model 6512 with the Model 7001, proceed as follows:
1. Connect the Model 6512 to the Model 7001 as shown in
Figure 2-22. Use shielded cables with BNC connectors.
The Model 6512 METER COMPLETE OUTPUT jack
should be connected to the Model 7001 EXTERNAL
TRIGGER input jack. The Model 6512 EXTERNAL
TRIGGER INPUT should be connected to the Model
7001 CHANNEL READY output. Additional connec-
tions, which are not shown on the diagram, will also be
necessary to apply signal inputs to the scanner cards, as
well as for the signal lines between the scanner and the
Model 6512.
2. Place the Model 6512 in the one-shot trigger mode by
pressing the SHIFT and TRIG buttons, in that order.
3. Install the desired scanner cards and make the required
input and output signal connections.
4. Program the Model 7001 scan list and trigger modes as re-
quired. See the Model 7001 Instruction Manual for details.
5. If data storage is required, enter the data storage mode
as described in paragraph 2.11.
READING
DONE
LS TTL HIGH
(3.4V TYPICAL)
10
µ
s
MINIMUM
BEGIN NEXT
CONVERSION
LS TTL LOW
(0.25V TYPICAL)
Summary of Contents for 6512
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