MMU-16LE
SmartMonitor
Operations Manual
Eberle Design Inc.
Page 12
2.9 OUTPUT RELAY RECOVERY
Prior to the MMU-16LE
SmartMonitor
®
transferring the Output Relay contacts from the fault
state to the no-fault state, a transition state with duration of 500 milliseconds will occur.
During the transition state the Output Relay will remain in the fault state and the Start-up
Flash Call bit in the Type 129 frame will be set to 1.
2.10 INTERNAL DIAGNOSTICS
The MMU-16LE
SmartMonitor
®
is supplied with a resident series of self check diagnostic
capabilities which monitor for correct operation of the MMU-16LE
SmartMonitor
®
both at
power-up and continuously during operation. Should an internal diagnostic error occur,
other fault indicators that may be concurrently displayed with the DIAGNOSTIC indicator
may not be valid due to the nature of these hardware and/or firmware failures.
2.10.1 MEMORY DIAGNOSTICS
On power-up, the MMU-16LE
SmartMonitor
®
verifies the operation of all memory
components including RAM, EPROM, and non-volatile EEPROM. During operation the
MMU-16LE
SmartMonitor
®
continuously performs a check sum verification of the non-
volatile memory components. When either diagnostic test fails, the MMU-16LE
SmartMonitor
®
will enter the fault mode, transfer the OUTPUT relay contacts to the Fault
position, and illuminate the DIAGNOSTIC indicator. An MMU Power Failure will reset the
Diagnostic fault state of the monitor (see Section 2.6). Due to the nature of these
hardware/firmware failures, other fault indicators that may be concurrently displayed with
the DIAGNOSTIC indicator may not be valid.
2.10.2 MICROPROCESSOR MONITOR
The MMU-16LE
SmartMonitor
®
contains circuitry which monitors the operation of the
internal microprocessor. This monitoring circuit receives a logic transition signal from the
microprocessor every 5 msec. When this logic transition is not received for 300 msec, the
MMU-16LE
SmartMonitor
®
will enter the fault mode, transfer the OUTPUT relay contacts to
the Fault position, and illuminate the DIAGNOSTIC indicator. Due to the nature of these
hardware/firmware failures, other fault indicators that may be concurrently displayed with
the DIAGNOSTIC indicator may not be valid.
This type of failure is configured as latching. If the microprocessor resumes operation the
unit will not return to normal operation. With latching operation, only a loss of AC Line will
restore operation. If non-latching operation is desired, internal jumper E1 (Latching MPU
Fault) may be removed.
2.10.3 INTERNAL HARDWARE MONITOR
The MMU-16LE
SmartMonitor
®
contains circuitry which verifies the operation of the many
sections of the internal circuitry. Should a malfunction be detected, the MMU-16LE
SmartMonitor
®
will enter the fault mode, transfer the OUTPUT relay contacts to the Fault
position, and illuminate the DIAGNOSTIC indicator. An MMU Power Failure will reset the
Diagnostic fault state of the monitor (see Section 2.6). Due to the nature of this hardware
failure, other fault indicators that may be concurrently displayed with the DIAGNOSTIC
indicator may not be valid.