MMU-16LE
SmartMonitor
Operations Manual
Eberle Design Inc.
Page 16
3.9 FIELD CHECK MONITORING
Field Check Monitoring is an enhanced function of the MMU-16LE
SmartMonitor
®
that
utilizes the Port 1 communications between the Controller Unit and the MMU in a TS2
Cabinet Assembly. When operating in the Type 16 mode the MMU-16LE
SmartMonitor
®
will
receive the Type 0 message from the Controller Unit (Type 1 or Type 2 CU) which contains
an image of the controller output commands to the load switches. When a fault condition
triggers the MMU-16LE, the Type 0 message information received while the fault condition
was being timed will be used by the MMU-16LE
SmartMonitor
®
to determine whether the
sensed field signal input status corresponded to the Controller Unit output commands. This
diagnostic information is then used by the Diagnostic Wizard to isolate whether the fault
condition was caused by a Controller Unit malfunction or a failure in the load switch and/or
field wiring. In the latter case, the Wizard then pinpoints the faulty inputs of the channels
involved in the fault condition.
The Field Check Monitor function is enabled for each channel input individually (see
Section 6.3.1) and provides two modes of operation,
Field Check Fault
and
Field Check
Status
.
3.9.1 FIELD CHECK FAULT
In the
Field Check Fault
mode, when the field signal input states sensed as active or
inactive by the MMU-16LE
SmartMonitor
®
do not correspond with the data provided by the
Controller Unit in the Type 0 message for 10 consecutive messages, the MMU-16LE
SmartMonitor
®
will enter the fault mode, transfer the OUTPUT relay contacts to the Fault
position, and display the FIELD CHECK FAULT status screen. The Channel Status Display
will indicate the channels on which the Field Check error was detected (see Section 7.2
Channel Status Display). Bit #67 (Spare Bit #1) of the Type #129 response frame will be
set to indicate a Field Check fault has been detected. The MMU-16LE
SmartMonitor
®
will
remain in the fault mode until the unit is reset by the RESET button or the EXTERNAL
RESET input. The Field Check Fail Monitoring function is automatically disabled in the
Type 12 mode, and in the Type 16 mode with the PORT 1 DISABLE input True (low). The
Field Check Fail Monitoring function is also disabled when the RED ENABLE input is not
active.
3.9.2 FIELD CHECK STATUS
The
Field Check Status
mode works in combination with the other fault monitoring
functions of the MMU-16LE
SmartMonitor
®
to produce additional diagnostic information
about the detected fault. The Field Check Monitor function will be collecting status and
timing a Field Check Fault if the sensed field signal input states do not correspond to the
Type 0 message data from the Controller Unit. When a Conflict, Red Fail, Clearance Fail,
or Dual Indication Fail triggers the MMU-16LE
SmartMonitor
®
, the Channel Status Display
and Main Status Display will correspond to that detected fault. If Field Check errors were
detected while the fault was being timed, the Main Status Display will add the text “+
FCstatus” to the fault type, The FIELD CHECK STATUS screen will also be available. Bit
#67 (Spare Bit #1) of the Type #129 response frame will be set to indicate Field Check
errors have been detected.
In a simple example, channels 2 and 6 are set to active Green by the controller. Channel 8
Green is not permissive with channels 2 and 6 and becomes active due to a short circuit in
the field wiring. The MMU-16LE
SmartMonitor
®
will detect a Conflict Fault with Field Check
Status on channel 8 Green. The main fault display text will show “Conflict with FC Status”.
Pressing the SELECT button will then display the actual Field Check status, which in this
example would show channel 8 Green only. The MMU-16LE
SmartMonitor
®
used the Field
Check function to directly pinpoint the faulty input (Channel 8 Green). Because of the Field
Check status it is also known that the Controller Unit did not drive the faulty input thus was
not involved in the fault.
The Diagnostic Wizard (HELP function, see Section 3.10) also uses the Field Check Status
to pinpoint faulty inputs in a more direct fashion.