MMU-16LE
SmartMonitor
Operations Manual
Eberle Design Inc.
Page 10
2.5.2.1 MINIMUM YELLOW PLUS RED CLEARANCE DISABLE
The Red + Yellow Clearance Disable Configuration screen is provided in the SET / VIEW
CONFIG menu to disable Minimum Yellow Plus Red Change Monitoring on a per channel
basis. Provision to disable this function is not provided for in the
NEMA
Standards
Publication TS2-2003 v02.06.
The
MUTCD Section 4D.10 Yellow Change and Red Clearance Intervals
requirement
states, “A yellow signal indication shall be displayed following every CIRCULAR GREEN or
GREEN ARROW signal indication”. In some legacy intersection cases this requirement is
not met due to the lack of a Yellow signal head on an overlap phase (channel), and signal
timing that precludes what would normally be the overlap clearance interval. In this case
the Minimum Yellow Plus Red Clearance monitoring function can be disabled for that
channel. It should be noted that the Minimum Yellow Plus Red Clearance monitoring
function is only intended to be disabled under these special conditions.
See Section 6.3.7 for the programming procedure. The default setting for Minimum Yellow
Plus Red Clearance monitoring is Enabled.
2.6 MMU POWER FAILURE DETECTION
When the AC LINE voltage is below the minimum AC Line drop-out level (Section 8.1.3) for
the MMU Power Fail Respond time (Section 9), the MMU-16LE
SmartMonitor
®
will suspend
all fault monitoring functions, de-energize the OUTPUT relay, and de-energize the START
relay. The POWER indicator on the front panel will flash at a rate of 2Hz to indicate the low
voltage status. The main status display will indicate “AC LINE BROWNOUT” and display
the current AC Line input voltage.
When the AC LINE voltage returns above the maximum AC Line restore level (Section
8.1.3) for the MMU Power Fail Restore time (Section 9), the monitor will resume normal
operation and the POWER indicator on the front panel will remain illuminated. After a 2.0 +
_
This expanded operating voltage range for cabinet components allows the MMU-16LE
SmartMonitor
®
to place the intersection into flash and return to normal operation in an
orderly manner when the AC LINE voltage is sufficient for proper operation. The MMU-
16LE
SmartMonitor
®
should be the first component in the cabinet to sense a low voltage
condition and the last component to sense a proper AC LINE operating voltage.
0.5 second delay the START relay will be energized. After a programmable delay
determined by the Minimum Flash programming, the OUTPUT relay will be energized (see
Section 6.2.2).
The AC LINE and AC NEUTRAL inputs are used to generate the internal voltage supplies
required to operate the monitor. AC NEUTRAL also serves as the return for all AC signals
including RED ENABLE. EARTH GROUND provides an independent connection to the
chassis of the unit and is isolated from AC NEUTRAL and LOGIC GROUND. LOGIC
GROUND is provided for inputs which are isolated from AC NEUTRAL (i.e. +24V Monitors,
CVM, CONTROLLER WATCHDOG, EXTERNAL RESET, and 24V MONITOR INHIBIT).
LOGIC GROUND may be tied to AC NEUTRAL if desired.
2.7 PORT 1 COMMUNICATIONS
When operating in the Type 16 mode and connected to a TS2 Controller Unit, the MMU-
16LE
SmartMonitor
®
has the ability to exchange information in a standardized format with
the Controller Unit using Port 1. For details on message formats refer to Section 3.3.1,
NEMA
Standards Publication TS2-2003 v02.06, Traffic Controller Assemblies With
NTCIP Requirements.
The information transmitted from the Controller Unit to the MMU-16LE
SmartMonitor
®
consists of the following message types: load switch driver commands (Type 0), time and
date (Type 9). The information transmitted from the MMU-16LE
SmartMonitor
®
to the
Controller Unit consists of the following message types: field signal status and fault status