Agilent Technologies 3499A/B/C - Manual (Page 8)

8
Scan Feature
The scan feature is a sequence of
alternating switch closures and
measurements. This feature is
provided by both the 34980A and
a 3499A/B/C combined with a
DMM or other measurement
instrument. The 34980A increases
the measurement scan abilities
and offers more than twice the
number of scanned channels
within one scan list compared to
the 3499A/B/C as seen here.
Single Scan List Size:
34980A Up to 560
2-wire channels
or
Up to 640
1-wire channels
3499A/B/C Up to 200 channels
and/or bits
Although the 34980A scan feature
can be used with either the
internal DMM or with an external
instrument, using the integrated
DMM provides a faster and more
efficient scan rate. The integrated
DMM eliminates the need for
external instrument triggers and
wiring. The 3499A/B/C scan list
requires the use of instrument
triggers to work with an external
DMM or other measurement
instrument. Each switch module is
rated with individual switch scan
rates. A comparison of the scan
rates for both systems Multiplexer
and Matrix switch modules is
shown in Table 5 below.
Another advantage the 34980A
system has over the 3499A/B/C
system is its ability to store
measurement readings. When the
34980A internal DMM is used, up
to 500,000 time stamped readings
can be stored in volatile memory.
The 3499A/B/C cannot store
readings but does offer more scan
configurability. For example,
once a 3499A/B/C scan list is set
up, the user can select an arm
source, a trigger source, the
number of sweeps, and the delay
time for each individual channel
within the scan list.
Module Type
34980A Scan Rate 3499A/B/C Scan Rate
Modules Ch/s Modules Ch/s
Multiplexer 34921A 40 Ch armature 100 N2260A 40 Ch armature 80
34922A 70 Ch armature 100 N2266A 40 Ch reed 350
34923A 40 Ch reed 500 N2270A 10 Ch 100
34924A 70 Ch reed 500 44470A 10 Ch armature 43
34925A 40 Ch FET 1000 44470D 20 Ch armature 43
Matrix 34931A Dual 4x8 armature 100 N2262A 4x8 armature 80
34932A Dual 4x16 armature 100 44473A 4x4 armature 43
34933A Dual 4x8 reed 500
Table 5. 34980A and 3499A/B/C Multiplexer & Matrix module scan rates