MMU-16LE
SmartMonitor
Operations Manual
Eberle Design Inc.
Page 15
3.7 RECURRENT PULSE DETECTION
This error detection function supplements the normal Conflict, Dual Indication, and Red Fail
monitoring algorithms for sensing faults which are intermittent or pulsing in nature. The
RMS-Engine
®
is designed to filter out short term transients commonly found on the
electrical service and provide noise immunity against false signal detections. The Recurrent
Pulse detection function is designed to respond to fault conditions which are intermittent in
nature and do not meet the continuous timing requirements of the normal detection
algorithms, yet may still produce improper signal displays. These input conditions are
differentiated by their longer time constant and fault response times.
The figure below shows a simple example of a Recurrent Conflict fault. Channel 2 Green is
detected active due to a malfunction of the load switch which caused the output to “flicker”
On for 100 ms approximately every 200 ms. Because normal Conflict detection requires a
continuous fault of at least 350 ms typical, this event could go undetected. The Recurrent
Pulse detection algorithm will process these pulses into one event and trigger a Conflict
fault once the longer recurrent timing threshold is exceeded.
When triggered by a recurrent pulse fault condition, the MMU-16LE
SmartMonitor
®
will
enter the fault mode, transfer the Output relay contacts to the Fault position, and display
the appropriate RP CONFLICT, RP DUAL INDICATION, or RP RED FAIL status screen.
The unit will remain in the fault mode until reset by the Reset button or the External Reset
input. Fault response times will vary depending on the pulse width and frequency of the
recurrent inputs, but typically range from 1000 ms minimum to 10 seconds maximum.
This function can be disabled by a UNIT Option called RECURRENT PULSE in the SET /
VIEW CONFIG menu. See Section 6.3.4.1.
3.8 TYPE FAULT
The TYPE SELECT input is used by the MMU-16LE
SmartMonitor
®
to specify whether the
monitor is to be configured as a Type 16 unit with 16 channels or a TS1 compatible Type
12 unit with 12 channels (see Section 1.4.2). This input is read by the MMU-16LE
SmartMonitor
®
only during power-up initialization or when the unit is reset by the RESET
button or EXTERNAL RESET input. The Type Select configuration of the MMU-16LE
SmartMonitor
®
can only be modified when the unit is reset by the RESET button or
EXTERNAL RESET input. This prevents the possibility of the MMU-16LE
SmartMonitor
®
changing its configuration mode due to the failure of the cabinet TYPE SELECT jumper or
the monitor TYPE SELECT input.
Once the unit is programmed by a reset command, its configuration mode (Type 16 or Type
12) is stored in non-volatile memory. During power-up initialization, the MMU-16LE
SmartMonitor
®
compares the programmed configuration mode with the state of the TYPE
SELECT input. If they are different, the MMU-16LE
SmartMonitor
®
will enter the fault mode,
transfer the OUTPUT relay contacts to the Fault position, and display the TYPE 12/16
FAULT status screen. The MMU-16LE
SmartMonitor
®
will remain in the fault mode until the
unit is reinitialized with the TYPE SELECT input in the proper state or the MMU-16LE
SmartMonitor
®
is reset by the RESET button or the EXTERNAL RESET input.