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The default configuration of the relays for Calisto and Calisto 2 is as shown below.
Two different “fail-safe” relay configurations may be of particular interest:
First, any of the relays may be configured to be “energized-when-always”. This relay then serves as
an indicator that the Calisto/Calisto 2 has lost power or stopped running.
Second, any relay can be configured to indicate loss of power OR a relay condition, by selecting the
“energized-when not-condition”.
When deciding on the use of N.O. or N.C. contacts, the fail-safe wiring configuration is that which
normally has current flow through the relay. In this way, an open circuit caused by a broken or
disconnected wire can also be detected.
Since the relays are controlled by the instrument firmware, fail-safe configurations will
generate client alarms when the instrument reboots or enters a pre-heating cycle.
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