MMU-16LE
SmartMonitor
Operations Manual
Eberle Design Inc.
Page 4
make enhanced event logging, remote intersection monitoring, and remote diagnostics
feasible. Similarly, the MMU-16LE
SmartMonitor
®
receives information from the Controller
Unit which corresponds to the Controller Unit output commands to the load switches. This
allows the MMU-16LE
SmartMonitor
®
to better respond to and diagnose fault situations.
The TS2 Standard also provides for messages to be generated by the Controller Unit and
the MMU-16LE
SmartMonitor
®
which extend the communications capabilities of a standard
assembly. The Eberle Design MMU-16LE
SmartMonitor
®
uses these message facilities to
provide enhanced application specific diagnostic reporting and monitoring.
1.4 FIELD SIGNAL TERMINALS
A GREEN, YELLOW, or WALK field signal input will be sensed as active by the MMU-16E
SmartMonitor
®
when it exceeds the Green, Yellow, or Walk Signal Detect voltage threshold
(Section 8.1.2) and a field signal input will be sensed as inactive when it is less than the
Green, Yellow, or Walk Signal No-Detect voltage threshold (Section 8.1.2). Both positive
and negative half wave rectified inputs will be sensed.
A RED (DON’T WALK) field signal input will be sensed as active by the MMU-16E when it
exceeds the Red Signal Detect voltage threshold (Section 8.1.2) and a field signal input will
be sensed as inactive when it is less than the Red Signal No-Detect voltage threshold
(Section 8.1.2). Both positive and negative half wave rectified inputs will be sensed.
NOTE:
1.4.1 LEDGUARD
®
LED FIELD SIGNAL SENSING
When the circuit connected to the sensing input of an MMU exhibits high
impedance characteristics such as caused by dimmers, burned out lamps, low wattage
equipment, or no load, it may be necessary to place a low impedance device external to the
unit between the MMU input and AC NEUTRAL (See Sections 5.5.3.9 and 6.2.4 of
NEMA
Standards Publication TS2-2003 v02.06, Traffic Controller Assemblies With NTCIP
Requirements
).
The Eberle Design MMU-16LE
SmartMonitor
®
can be configured to use a technique called
LEDguard
®
that is designed to better monitor the characteristics of LED based signal loads
(See Section 6.3.4.7). Each field signal input is measured and compared to both a high
threshold and a low threshold value to determine On / Off status. This differs from
conventional standard Nema operation where the active threshold is picked according to
the color of the field signal. Once the high and low On / Off thresholds (Section 8.1.2) have
been determined using the input RMS voltage, the individual fault monitor functions use the
appropriate threshold to determine if a fault condition exists.
LEDguard
®
Green/Walk
Yellow
Red/Don’t Walk
Conflict
Low
Low
---
Red Fail
High
High
High
Dual Indication
Low
Low
Low
Clearance
Low
Low
High
1.4.2 TYPE SELECT INPUT
The MMU-16LE
SmartMonitor
®
will operate as a Type 16 monitor with sixteen channels
when the TYPE SELECT input is a logic True (low). The MMU-16LE
SmartMonitor
®
will
operate as a Type 12 monitor with twelve channels when the TYPE SELECT input is a
logic False (high) or open circuit.
Type 16 - Each channel has three inputs: RED (DON’T WALK), YELLOW, and
GREEN (WALK).
Type 12 - Each channel has four inputs: RED, YELLOW, GREEN, and WALK.
The MMU-16LE
SmartMonitor
®
is normally configured as a 16 channel (Type 16) monitor
when operated in a TS2 type cabinet assembly. The Type 12 mode is intended to provide
downward compatibility with 12 channel Conflict Monitor Units (CMU) conforming to NEMA