Signametrics Corporation SM4020, Operator'S Manual

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7 Signametrics
1.4 Configurations
In addition to the channel switching relays, the SM4000 series includes two sets of relays used for configuring of
the scanner. The configuration switches facilitate inter-group connections and the Tree relays provide isolation of
each of the group’s buses from their respective channel relays. These relays are automatically switched on the fly
when the scanner receives configuration commands or changes are required while selecting channels from various
groups. In cases where the pre-defined configurations (
TwoWire, FourWire, SixWire, TwoGroups, and FourGroups )
do not meet the test needs, select the Universal configuration. It allows an unlimited control any of the configuration
and tree relays independently. Care must be taken however, since it does not offer the protection of the predefined
configurations. This could result in shorting some “hot” lines, constituting in potential hazard to the user from any
thing that is connected to the scanner and from the scanner itself. This could also lead to damaging the scanner or
anything connected to it.
1.5 Self Test and Contact Cleaning
In addition to the channel relays, Tree relays and Configuration relays, there are additional relays and circuit
components that handle the various tests built into the Scanners. The user does not have direct control of these
components.
The test connector is used in various self tests and cleaning operations of the Scanner. It is a Female DIN 96
position connector which has 40 shorts across all Channels (Ch1Hi shorted to Ch1Lo etc.), and three shorts across
the B-Bus, C-Bus and D-Bus. All other terminals, including the A-Bus must be left open. This Test Connector is
optionally available from Signametrics.