Agilent Technologies L4400 - Manual (Page 96)

84 L4400 User’s Guide
3 Operating and Programming
• You can configure the list of channels for 4- wire external scanning.
When enabled, the instrument automatically pairs channel n in Bank 1
with channel n+20 in Bank 2 to provide the source and sense
connections. For example, make the source connections to the HI and
LO terminals on channel 2 in Bank 1 and the sense connections to the
HI and LO terminals on channel 22 (or 37) in Bank 2.
To configure the instrument for 4- wire external scanning, send the
following command.
ROUTe:CHANnel:FWIRe {OFF|ON}, (@<ch_list>)
The following program segment configures a separate DMM and the
L4421A for one pass through a scan list of 10 channels (Figure 3- 14).

CONF:RES AUTO, DEF

TRIG:SOUR EXT

TRIG:COUN 10

INIT


ROUT:SCAN (@1001:1010)

ROUT:CHAN:ADV:SOUR EXT

INIT
Configure DMM function (resistance)

Set DMM trigger source

Set DMM trigger count

Put DMM in wait- for- trigger state


Set L4421A scan list

Set L4421A channel advance source

Initiate the scan (close first channel)
The L4400 Product Reference CD- ROM (p/n 34989- 13601) included with
the L4400 instruments contains complete examples (VISA, VISA- COM,
IVI- COM) of scanning L4421A channels using a separate DMM. The
example is in the folder “Mux_L4421A.”
Alarm Limits
Usage:
• L4450A 64- Bit Digital I/O (digital input, counter channels only)
• L4452A Multifunction Module (digital input, totalizer channels only)
You can configure the instrument to generate an alarm when a specific

bit pattern or bit pattern change is detected on a digital input channel

or when a specific count is reached on a totalizer channel of the L4450A
and L4452A. These channels do not have to be part of the scan list to
generate an alarm. Alarms are evaluated continuously as soon as you
enable them.
There are two alarm paths that can be configured to alert you when
specific alarm conditions are encountered during a scan. You can assign
multiple channels to either of the two available alarms (ALARm1,
ALARm2).
Alarm data can be stored in one of two locations depending on whether
a scan is running when the alarm occurs.