CMU-24VDC-ITL Cabinet Monitor Unit
Operations Manual
Eberle Design Inc.
Page 2
AMU #1 AMU #2 AMU #3 AMU #4 Monitored Channels
6
6
none
None
1 thru 12
6
6
6
None
1 thru 18
6
6
6
6
1 thru 24
6
none
14
reserved
1 thru 20
6
6
14
reserved
1 thru 26
The ATC must verify that all output assemblies being driven by a Serial Interface Unit
(SIU) are being monitored by an AMU-24VDC and that the AMU-24VDC is enabled by
the programming in the CMU-24VDC. Failure to provide this check may result in
unmonitored load switch outputs.
This could occur as a result of improper configuration
of the cabinet, improper address assignment for one or more AMU-24VDC units, improper
address assignment for one or more SIU units, or improper programming of the ATC.
1.4 CMU-24VDC PROGRAMMING
The CMU-24VDC is individually configured using a removable nonvolatile memory device
called a Datakey
tm
(Datakey is a registered trademark of Datakey Electronics, Inc.). The
Datakey replaces the mechanical jumper or diode based program card used in
conventional signal monitors and provides an electronic method of programming the CMU-
24VDC. The Datakey contains a nonvolatile prom device that is read by the CMU-24VDC.
The Datakey itself is programmed by a separate programming device using a Personal
Computer program such as the Eberle Design MonitorKey product. See the Eberle Design
MonitorKey Operations Manual
for further details.
The Datakey is interoperable with any CMU-24VDC meeting the requirements of the
ASHTO/ITE/NEMA
Intelligent Transportation System (ITS) Standard Specification for
Roadside Cabinets
Version 01.02.17b
.
1.5 ECCOM SOFTWARE INTERFACE
The front panel display of the CMU-24VDC provides limited operational status. This status
includes real time indicators for Power, Serial Bus #1 activity, Serial Bus #3 activity, and
eleven latched indicators for fault conditions. Detailed status is obtained through the front
panel port using Eberle Design
ECcom
software running on a personal computer. The
ECcom software provides access to real time monitor data such as current field signal
status, field terminal voltages, cabinet control voltages, channel load current status,
temperature, and fault status. Historical event logs and signal sequence logs are also
provided. See the Eberle Design
ECcom Operations Manual
for further details.
1.6 SERIAL BUS #1
Serial Bus #1 provides a communication path between the CMU-24VDC to the ATC. The
communications between the ATC and the CMU-24VDC plays an integral role in ensuring
safe and proper operation of the cabinet equipment as well as providing important
diagnostic functions used for trouble shooting malfunctioning equipment. Standardized
communications can be broken into three categories; real time and latched fault status,
configuration verification, and malfunction detection and diagnosis.
Messages are defined that allow the ATC and the CMU-24VDC to perform redundant
checks on each other. The ATC has access to all CMU-24VDC information including field
signal input status, permissive programming, and fault status. This gives the ATC the
capability to provide a backup monitoring function and make enhanced event logging,
remote intersection monitoring, and remote diagnostics feasible. Similarly, the CMU-24VDC
receives information from the ATC that corresponds to the output commands to the load
switches. This data allows the CMU-24VDC to better respond to and diagnose fault
situations.
