Example: Scanning
Using "Trig Out" and
"Event In" Ports
Chapter 4
This example uses the mainframe "Trig Out" and "Event In" ports to
synchronize the multiplexers to an Agilent 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. Note that the pulse output
from the multimeter's "VOLTMETER COMPLETE" port triggers the
switchbox to advance the channel list. Use the multimeter's reading storage
capability to store readings.
The sequence of operation is:
1.
(line 50) closes channel number 100.
INIT
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 stored into multimeter memory.
5. Trigger is output from multimeter's "VOLTMETER COMPLETE"
port.
6. Trigger to "Event In" port advances the channel list to the next
channel.
7. Steps 2-6 are repeated for channels 101 through 115.
10 OUTPUT 722;"TRIG EXT;DCV;MEM FIFO"
20 OUTPUT 70914;"OUTP ON"
30 OUTPUT 70914;"TRIG:SOUR EXT"
40 OUTPUT 70914;"SCAN (@100:115)"
50 OUTPUT 70914;"INIT"
60 END
Understanding the Relay Multiplexer Modules
!Sets multimeter to external
trigger; to measure dc volts, and
store readings.
!Enables "Trig Out" port.
!Sets switchbox to receive
external triggers.
!Selects the channel list
(channels 100 to 115).
!Starts scanning cycle.
45