Agilent Technologies E8462A, User Manual

Page: 48 / 156

46 Using the Multiplexer
You can scan a channel or a list of channels using the
SCAN
command. The
analog bus connection control relays (CH9200-9204) are automatically
closed when you specify the command
SCAN:PORT ABUS
. This command
is required for the analog bus control relays to function during the scan
through the channel list. The default value is
SCAN:PORT NONE
which
does not automatically close these relays and connect channels to the analog
bus. They may however, still be manually controlled with the OPEN and
CLOSe commands.
At power-on or after resetting the module with the
*RST
command,
connection to the analog bus is disabled for scan operations. You must
execute the command
SCAN:PORT ABUS
to enable analog bus connection
control relay operation. Access is through the front panel analog bus
connector (usually connected to other multiplexers or to the E1411B
multimeter) or through the terminal module (Opt 014) “VM Input” and “

I”
terminals on P109 connector (see Figure 1-1 on page 13).
Synchronizing the
Multiplexer with a
Multimeter
This example uses the TTL VXIbus triggers ( TTLT 0-7 ) to synchronize
channel closures with the Agilent E1412A 6 1/2-Digit Multimeter. DC
Voltage measurements are performed. Measurement synchronization is
attained by the multimeter sending a voltmeter complete signal on TTL
Trigger Line 1 and receiving the channel closed signal on TTL Trigger Line
0. Similarly, the multiplexer module sends its channel closed signal on TTL
0 and receives its channel advance signal on TTL 1. Note; Figure 2-8 shows
connections between the Agilent E1406A Command Module Trigger In and
Trigger Out to the Agilent E1412A Trigger In and Voltmeter Complete. This
simply demonstrates an alternate method of synchronizing the
measurements.
Measurement Set-Up
•
Agilent E1412A has an GPIB select code = 7, primary address = 09
and secondary address = 03.
•
Agilent E8462A has an GPIB select code = 7, primary address = 09
and secondary address = 14.
•
Controller is an IBM compatible PC, the programming language is
Visual C/C++ with Agilent VISA extensions.