Bently Nevada 3300/46, Operation Manual

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Ramp Differential Expansion Monitor Operation 84413-01
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MONITOR FUNCTIONS
RAMP DIFFERENTIAL EXPANSION - The Ramp Differential Expansion Monitor provides continuous
monitoring of shaft growth relative to the machine case. Normal expansion direction can be toward
or away from the probe A.
PROBE GAP VOLTAGE - Probe gap is measured as a negative dc voltage that is directly proportional
to the gap distance between the face of a proximity probe and the surface being monitored. Probe
gap voltage for each channel is displayed on the front panel meter by pressing the GAP switch.
OK - When the Proximitor output voltage is within its upper/lower limits, the transducer is defined as
OK. The OK detection circuit controls the channel OK LED and the monitor relay drive to the system
OK relay. If the monitor has the latching Not OK option, a System Reset is required to reset the OK
function.
OK RELAY - The OK relay is located on the Power Input Module. Every channel in the rack must
be OK or bypassed to energize the OK relay.
ALARM - Pressing the ALERT and DANGER switches on the front panel of the monitor causes the
Alert (first-level alarm) or Danger (second-level alarm) setpoints to be displayed on the front
panel meter. ALERT and DANGER LEDs come on when the differential expansion signal level exceeds
preset levels for the selected time delay, and appropriate Alert and Danger alarm relay contacts are
activated.
FIRST OUT - Separate First Out circuits exist for Alert and Danger alarms. A monitor with First Out
option selected flashes the LONG or SHORT alarm LED if that particular alarm was the first alarm
since the last reset. Pressing the RESET switch acknowledges the First Out.
ALARM RELAYS - Monitor alarms can be programmed for either the latching or nonlatching mode.
In the nonlatching mode, the alarm resets automatically when the alarm no longer exists. In the
latching mode, the alarm condition must be reset manually by pressing the RESET switch on the front
panel of the System Monitor (or by closing external Reset contacts). The alarm will not reset if the
alarm condition still exists.
DANGER BYPASS - For maintenance functions, a Danger Bypass switch on the monitor circuit board
behind the front panel can be set to inhibit the Danger relay drive. This function causes the BYPASS
LEDs to be turned on. Other front panel functions are not affected. This function can be enabled by
installing a jumper on the monitor.
BUFFERED OUTPUT - The Channels A and B coaxial cable connectors on the front panel of the
monitor and terminals on the Signal Input Relay Module provide buffered signals from respective
channel transducers. These connectors can be used for connection of external equipment.
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