User`s manual

44 Understanding the Relay Multiplexer Modules Chapter 4

Example: Scanning With

External Devices

This example uses the mainframe "Trig Out" port 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. The sequence of operation is:

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).

TRIGGER (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:MODE VOLT"

!Sets switchbox to measure

voltage.

50 OUTPUT 70914;"SCAN:PORT ABUS"

!Closes the AT and AT2 Tree

Switches.

60 OUTPUT 70914;"SCAN (@100:115)"

!Selects the channel list for

scanning.

70 OUTPUT 70914;"INIT"

!Starts scanning cycle.

80 FOR I=1 TO 16

!Start count loop.

90 ENTER 722;A

!Enter reading into variable A.

100 PRINT A

!Print reading in variable A.

110 TRIGGER 70914

!Trigger the switchbox to

advance the channel list.

120 NEXT I

!Increment count.

130 END