bus, forming one group, and, Ch11 through Ch20 to the B-bus, forming the second group. The SM4040 and
SM4042 route Ch1 to Ch20 to the A-bus forming the first group, and Ch21 through Ch40 to the C-bus, forming the
second group.
4.1.5 Four Groups Configuration
In the
FourGroup
configuration, the SM4040 and SM4042 provide four independent multiplexing groups. The
groups function as independent two wire multiplexers. When a channel is selected, any closed channel within the
selected group is opened, followed by the closure of the selected channel. It’s like having four individual switching
modules. Ch1 to Ch10 are routed to the A-bus forming the first group. Ch11 to Ch20 are routed to the B-bus
forming the second group. Ch21 to Ch30 are routed to the C-bus forming the third group. Ch31 through Ch40 are
routed to the D-bus to form the fourth group.
Figure 4-4
.
In the Four Groups configuration, four independent 2-Wire scanners are available.
4.1.6 Disabled
In the Disabled configuration, all relays, including channel and configuration relays are open. This is the default
configuration, selected on power up, or initialization.
4.2 Scanner Operations
In addition to basic scanner operations such as selecting channels, the SM4000 series has several built-in operations,
which it more versatile and a lot more capable. These operations include various self-diagnostics procedures,
contact cleaning, and auto scanning and interfacing to external test and measurement instruments.
4.2.1 Trigger Output
The trigger output line,
TRIG_out
, maybe enabled or disabled as well as set for a positive or negative polarity
using the
SCANTriggerOutState()
command. Under normal operation, the
TRIG_out
line is active for the
duration of the Actuation time. It maybe used to drive or synchronize other test equipment. If set to positive
polarity, a positive edge indicates the selected channel is closed and settled, provided the correct Actuation time is
set (use
SCANSetActuationTime()
function to set it). The logic level of TRIG_out may be set high or low using
Signametrics
18
Summary of Contents for SM4020
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