Section 2 - MONITOR FUNCTIONS
3
monitor in the rack. The OK Circuit continuously checks the condition of the transducer(s)
associated with that monitor. If the circuit detects a transducer problem, the OK LED on the front
of the affected monitor goes off and a relay drive signal is sent to the OK Relay in the System
Monitor.
The OK Relay is located on the System Monitor PIM, is normally energized, and is a single-pole,
double-throw (SPDT) relay. Since it is normally energized, the relay also can be used to
annunciate when mains power to the rack is lost or interrupted. Either a system power-up inhibit
signal from the System Monitor or a not OK signal from any monitor in the rack will cause the OK
Relay to change state.
ALARM SETPOINT ADJUST
The System Monitor has two switches on the front panel that adjust alarm setpoint levels on each
monitor. One switch is for upscale adjustments, and the other switch is for downscale
adjustments.
DATA INTERFACE
The System Monitor supports the following Bently Nevada data interfaces: Dynamic Data
Manager (DDM), Transient Data Manager
®
(TDM), Serial Data Interface (SDI), Dynamic Data
Interface (DDI) and Transient Data Interface (TDI). The SDI and DDI are options of the System
Monitor and reside within the System Monitor slot of the rack. DDM, TDM and TDI are external
data interfaces which gain access to the rack through the PIM. There is an external version of the
SDI and DDI which connects to the PIM. For more information about these products consult a
Bently Nevada sales representative.
Keyphasor
®
TRANSDUCERS
The System Monitor receives input from four Keyphasor
®
transducers through terminals on the
PIM. Two of the Keyphasor
®
transducers are available to the monitors within the rack. All four of
the Keyphasor
®
transducers are available to the Dynamic Data Interface (DDI). Buffered
Keyphasor
®
signals are also available from the coaxial connectors on the front panel. The System
Monitor also provides short-circuit protected Keyphasor
®
transducer power.
STATIC DATA BUS BUFFER
The System Monitor multiplexes signals from either the DDM or TDM to select static data
from the monitors. The System Monitor buffers the static data signals sent from the
monitor to the DDM or TDM.
