User manual

44 Using the Relay Multiplexer Chapter 2
Scanning Requirements of a Switchbox (With a Command Module). To scan
modules in a switchbox, you must nnow the card numbers of all the modules
to be scanned, sequentially address the modules (for example, logical
address 112, 113, 114, etc.), and set the lowest addressed module to a
logical address that is a multiple of 8.
Channel List Can Be Extended Across Boundaries. For multiple-module
switchbox instruments, the channels to be scanned can extend across
switch modules. For example, for a two-module switchbox instrument,

SCAN (@100:277) will scan all channels of both multiplexer modules.
Setting Multiple Continuous Scans. Use ARM:COUNt <number> to set from
1 to 32767 scans. Use INITiate:CONTinuous ON to set continuous
scanning.
Control Relay Switching. Control relays (0990 to 0996) are not affected by
opening and closing of the channel relays (banks 0 to 7). They are switched
when configuring a mode (See "Channel Switching" in this chapter), and
during scanning when SCAN:PORT ABUS is selected (see the
[ROUTe:]SCAN:PORT command for more information).
Two-Wire Ohms Measurements. When making two-wire ohms scanning
measurements using multimeters with SOURCE/SENSE leads, use
SCAN:MODE RES. When making two-wire ohms scanning measurements
using multimeters with HI/LO leads, use SCAN:MODE VOLT. See the
[ROUTe:]SCAN:MODE command for more information.
Scanning Channels
Examples
Some example programs follow that show how to scan channels using the
E1406A Command Module and/or external multimeters. The examples are:
• Example: Scanning Channels Using E1406A Command Module
• Example: Scanning Channels Using E1412A Multimeter
• Example: Scanning Channels Using 3457A Multimeter
• Example: Scanning Multimeter DCV Measurements
• Example: Scanning Multimeter Resistance Measurements
Example: Scanning
Channels Using E1406A
Command Module
This example uses the E1406A Command Module TTL Trigger Bus lines to
synchronize E1460A multiplexer bank 0 channel 0, to bank 7 channel 7
closures to an E1411B System Multimeter. For the example, a two-wire
ohms measurement is performed.
For measurement synchronization, E1406A TTL Trigger Bus line 0 is used
by the multiplexer to trigger the multimeter to perform a measurement.

The E1406A TTL Trigger Bus line 1 is used by the multimeter to advance the
multiplexer scan.
Figure 2-6 shows how to connect the E1460A multiplexer module to the
E1411B multimeter. This example uses GPIB select code 7, primary
address 09, and secondary address 03 for the multimeter and GPIB select
code 7, primary address 09, and secondary address 14 for the multiplexer.