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%ST
:TRIGger:SEQuence:COLNt:ALITo ON"
:ROUTe:SCAN clistz
:DJIl-
The first command resets the mainframe to a default
scan configuration. The second command automatical-
ly sets the channel count to the number of channels in
the Scan List, the third command defines the Scan List
and the fourth command takes the Model 7001 out of
the idle state.
The following
program will perform a single scan
through all 40 channels of a multiplexer card installed
in slot 1:
10 ouTI?uT 707; "%w'
20 OUTPUT 707;
":&ig:seqxoun:aufo on-
30 OUTPUT 707;":scan (@1!1:1!40)"
40 0uTMlT707;":ini~
50
END
Line 10 Selects a default conQuration
for the scan.
Lie 20 Set.5 ckannd count to the scan-list-length.
Line30
Definesthescml.ist.
Line 40 Take the Model 7001 out of the idle state. The
scan is coniigmd
to start as soon as this
command is executed.
When the above program is run, the scan will be com-
pleted in approximately 240 milliseconds (3msec delay
for each relay close and a 3msec delay for each open),
which is too fast to view from the front panel. An addi-
tional relay delay can be added to the program to slow
down the scan for viewing. The program is modified
by adding line 25 to slow down the scan. Also, Line 5 is
added to the beginning of the program to ensure that
all channels are open before the scan is started.
5
OUTPW
707;
":open alY
10
0IJTmT707;"*RsY
20 OUTPUT 707;
":trig:seq:coun:auto on"
25 OUTPU'I 707;
":trigzdelO.Z5"
30 0uTruT707;":scan
(@ 1!1:1!40)"
40 0InPuT707;
":W
50 END
Line5
opensallchanneL5.
Line25
Sets a l/4 second delay after each channel
closes.
4.4
Multiplexer
switching
examples
This paragraph presents some typical applications for
the Model 7011. These include resistor testing, transis-
tor testing, and resistivity testing, which shows how to
use the Model 7011 with a matrix card (Model 7012).
4.4.1
Resistor testing
The Model 7011 can be used to test a large number of
resistors using only one test instnunent or group of in-
struments. Such tests include two-wire and four-wire
resistance measurements using a DMM, and low-resis-
tance measurements using a current source and sensi-
tive digital voltmeter, as discussed in the following
paragraphs.
Two-wire resistance tests
Figure 4-1 shows a typical test setup for making two-
wire resistance measurements. The Model 7011 card
provides the switching function, while the resistance
mea.sUTements are made by a Model 199 DMM. Since
only two-pole switching is required for this applica-
tion, one Model 7011 card can be used to switch up to
40 resistors (additional multiplexer banks can be add-
ed, if desired, by adding more cards).
Accuracy of measurements can be optimized by mini-
mizing sway resistance.
Make connecting wires as short as possible to mini-
mize path resistance. Another technique is to short one
of the multiplexer
inputs, close the shorted channel
and then enable the DMM zero feature to cancel path
resistance. Leave zero enabled for the entire test.
4-5
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Troubleshooting
