Operator`s manual

Figure 4-2. To perform 4-Wire resistance measurement with the SM4042, connect Ch1 and Ch21 to a resistor,
maintaining correct polarity.
4.1.3 Six Wire Multiplexing
In SixWire configuration, the SM4040 and SM4042 simultaneously connect one channel to the A-bus, one to the B-
bus and one to the C-bus. Selecting a channel automatically closes three channel relays. For instance, selecting
channel 2 results in the opening of all currently closed channel relays, followed by the closure of Ch2, Ch12, and
Ch22. Each is routed to the A-bus, B-bus, and C-bus, respectively. To measure a resistor using 6-Wire guarded
connection, the A-bus is connected to the DMM source leads, the B-bus to the sense leads and the C-bus to the
Guarded point. Make sure the polarity of the lines is consistent. It should e noted that the ‘D’ group, consisting of
Ch31 to Ch40, is available independently to provide additional 10 channels of 2-Wire multiplexing.
Figure 4-3. In the 6-Wire configuration, the three lead sets are switched simultaneously.
4.1.4 Two Groups Configuration
In the TwoGroup configuration, the SM4000 family provides two independent multiplexing groups. Both groups
function as two independent two wire multiplexers. When a channel is selected, any closed channel within that
group is opened; next, the selected channel is closed. The SM4020 and SM4022 route Ch1 through Ch10 to the A-
17 Signametrics