Example: Scanning
With External
Devices
This example uses the mainframe "Trig Out" port to synchronize the
multiplexer to an HP 3457A Digital Multimeter. See the following figure
for typical connections.
For this example, use the trigger output pulse of the mainframe "Trig Out"
port to trigger the multimeter via its External Trigger port. The sequence of
operation is:
1. INIT (line 70) closes channel number 100.
2. The channel closure causes a trigger output from the "Trig Out" port.
3. The trigger causes the multimeter to make a measurement.
4. Measurement result is sent to the computer (lines 80 to 100).
5. TRIGGER command (line 110) advances the channel list to the next
channel.
6. Steps 2-5 are repeated for channels 101 through 115.
10 OUTPUT 722;"TRIG EXT;DCV"
! Sets multimeter to external
trigger and to measure dc volts
20 OUTPUT 70914;"OUTP ON"
! Enables "Trig Out" port
30 OUTPUT 70914;"TRIG:SOUR BUS"
! Sets switchbox to receive Bus
triggers
40 OUTPUT 70914;"SCAN (@100:247)"
! Selects the channel list for
scanning
50 OUTPUT 70914;"INIT"
! Starts scanning cycle
60 FOR I=1 TO 96
! Start count loop
70 ENTER 722;A
! Enter reading into variable A
80 PRINT A
! Print reading in variable A
90 TRIGGER 70914
! Trigger the switchbox to advance
the channel list
100 NEXT I
! Increment count
110 END
36 Understanding the HP E1346A Multiplexer
Chapter 4
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