Relay Switching Examples; Controlling Sources, Supplies And Loads - Keithley 7013-S Instruction Manual

Operation
The first command resets the mainframe to a default
scan configuration. The second command automati-
cally 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 20 channels of a 7013 relay card installed in
slot 1:
10 OUTPUT 707; "*RST"
20 OUTPUT 707; ":trig:seq:coun:auto on"
30 OUTPUT 707; ":scan (@ 1!1:1!20)"
40 OUTPUT 707; ":init"
50 END
Line 10 Selects a default configuration for the scan.
Line 20 Sets channel count to the scan-list-length.
Line 30 Defines the scan list.
Line 40 Take the Model 7001 out of the idle state. The
scan is configured to start as soon as this
command is executed.
When the above program is run, the scan will be com-
pleted in approximately 120msec (3msec delay for each
relay closed and a 3msec delay for each open), which is
too fast to view from the front panel. An additional
relay delay can be added to the program to slow down
the scan for viewing. The program is modified by add-
ing line 25 to slow down the scan. Also, Line 5 is added
to the beginning of the program to ensure that all chan-
nels are open before the scan is started.
5 OUTPUT 707; ":open all"
10 OUTPUT 707; "*RST"
20 OUTPUT 707; ":trig:seq:coun:auto on"
25 OUTPUT 707; ":trig:del 0.25"
30 OUTPUT 707; ":scan (@ 1!1:1!20)"
40 OUTPUT 707; ":INIT"
50 END
Line 5 Opens all channels.
Line 25 Sets a 1/4 second delay after each channel
closes.
4-6
4.4

Relay switching examples

The independent IN/OUT circuits for each channel
provide the means for some unique switching systems,
some of which are described in the following
paragraphs.

4.4.1 Controlling sources, supplies and loads

Figure 4-6 shows an example of a system that tests a
DUT (device under test) by measuring its output. Of
course the DUT can be tested by connecting the source,
supply, and load directly to the DUT. However, switch-
ing these devices allows you to test the DUT under a
variety of different conditions.
With the DUT properly biased (Channel 3 closed) you
may want to test the output under three different input
conditions; the normal source signal (Channel 1 open,
Channel 2 closed), an open input (Channels 1 and 2
open), and a shorted input (Channel 1 closed, Channel
2 open).
CAUTION
To prevent possible damage to the
source, do not allow Channels 1 and
2 to be closed at the same time. Doing
so will short the output of the source.
Isolation between the input and output can be tested.
By removing the power supply (Channel 3 open) the
DUT can be tested to see if any part of the input signal
appears at the output.
Output regulation of the DUT can be tested by compar-
ing the output with load (Channel 4 closed) and with-
out load (Channel 4 open).