Agilent Technologies E8462A, User Manual

Page: 53 / 156

Using the Multiplexer 51
Using BUS Triggers
with an External Device
to Scan Channels
Refer to Figure 2-9. This example uses the
BUS
trigger (
GET
or
*TRG
) to
synchronize channel closures with the Agilent 3457A Multimeter. A DC
voltage measurement is performed. Measurement synchronization is
attained by:
1. After the multimeter and multiplexer are configured, iniitate the scan
on the Agilent E8462A ( INIT command). This closes the first channel.
2. FETCH? the reading from the multimeter.
3. Trigger the multiplexer (*TRG command). This opens the channel
and closes the next channel in the list. After the relay settles, the
Agilent E1406A outputs a trigger to trigger the multimeter.
4. Repeat steps 2 and 3 in a loop until all channels in the channel list
have been scanned.
The actual C++ language program is similar to the previous example and
will not be presented again.
Hybrid MUX
Configuration
The module can be configured into segments of channels that are of different
modes using the FUNCtion NONE and manually setting appropriate tree
switches. Figures 1-1 and 2-1 through 2-6 show the location of tree relays
and will help you determine what relays you should close. An example
program on the driver CD (in the examples subdirectory) titled hybrid.c
configures part of the module as 1-wire, part as 2-wire and part as 4-wire.
Distribution MUX
You can use the multiplexer to distribute a signal to many different channels
as well as multiplexing many channels into one signal line. The example
program distrib.c on the drivers CD (in the examples subdirectory) shows
how a signal input on terminal line TER0 can be distributed to 128 different
channels.
Figure 2-9. Scanning with an External Device