User`s guide

Chapter 2 Front Panel Operations RIGOL
M300 User’s Guide
2-47
To Control MC3120
MC3120 is a 20-channel multiplexer (MUX-20 for short). MC3120 is divided into two
banks of 10 two-wire channels (HI and LO) each and can be used for 2-wire and
4-wire connections. When making 4-wire resistance measurement, the instrument
automatically pairs channel n with channel n+10 (wherein, n is an integer between 1
and 10). MC3120 is used with the external terminal block (M3TB20) which has a
built-in thermocouple reference junction.
01
H
L
H
L
...
H
L
H
L
...
DMM
Source
H
L
DMM
Sense
H
L
10
11
20
Bank Switch
Channel Switches
98
99
97
Backplane Switches
H
L
Com
(4W Sense)
H
L
Com
Signals
to be
Measured
Reference
Junction
Terminal Blocks: M3TB20
H
L
01
H
L
20
.
.
.
78-Pin
Interface
Figure 2-14 MC3120 Schematic Diagram
The control interface of MC3120 is as shown in Figure 2-15. Use the up/down and
left/right direction keys to select the desired channel. The channel currently selected
is highlighted, for example,
. You can perform various operations on the channel
currently selected (such as open or close the channel).