Signametrics Corporation SM4020, Operator'S Manual

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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