MMU-16LE
SmartMonitor
Operations Manual
Eberle Design Inc.
Page 11
(Type 129), channel compatibility programming (Type 131). The load switch driver
command (Type 0) and field signal status (Type 129) messages are exchanged
approximately every 100 msec.
The electrical interface used for Port 1 conforms to the requirements of the Electronic
Industries Association EIA-485 Standard. It is designed for balanced digital multipoint bus
systems and provides fully differential signal operation. The baud rate used is 153.6K bit
per second. The Port 1 connector intermates with a 15 pin D type connector, AMP
Incorporated part number 205206-1 or equivalent. The Port 1 connector pin assignments
are shown in Section 10.6.
The data and clock communications protocol used for Port 1 is a subset of the
Synchronous Data Link Control (SDLC) Protocol, as defined by
International Business
Machines Corporation Document GA27-3093-3 (June 1986)
. This protocol utilizes
sophisticated error checking computations to verify message integrity. In addition, the
Eberle Design MMU-16LE
SmartMonitor
®
adds enhanced communications diagnostics and
error handling capabilities to ensure proper communications occur.
2.7.1 PORT 1 TIMEOUT
When a Type 0 message from the Controller Unit has not been correctly received for the
Port 1 Timeout Fault time (Section 9), the MMU-16LE
SmartMonitor
®
will enter the fault
mode, transfer the OUTPUT relay contacts to the Fault position, and display the PORT 1
FAIL status screen. When receipt of a Type 0 message again occurs, the MMU-16LE
SmartMonitor
®
will exit the fault state and transfer the OUTPUT relay contacts to the normal
position, except when three Port 1 faults have occurred in a calendar day.
After the third Port 1 fault in a calendar day, the MMU-16LE
SmartMonitor
®
will remain in
the fault mode until the unit is reset by the RESET button or the EXTERNAL RESET input.
Loss of AC Line after the third Port 1 fault will exit the fault state and reset the Port 1 fail
count to 2.
A PORT 1 timeout failure during the programmed Minimum Flash time or during an MMU
Power Failure will not cause a latched fault condition.
2.7.2 PORT 1 DISABLE INPUT
Port 1 communications will be disabled when the PORT 1 DISABLE input is at a logic True
(low) state OR the TYPE SELECT input is at a logic False (high) state (Type 12 mode).
Port 1 communications will be enabled when the PORT 1 DISABLE input is at a logic False
(high) state AND the TYPE SELECT input is True (low) (Type 16 mode).
2.8 TYPE 129 RESPONSE FRAME
Five bits designated as Spare Bit #1 through Spare bit #5 of the Type 129 response frame
to the Controller Unit are used by the MMU-16LE
SmartMonitor
®
to indicate the type of
failure detected for enhanced fault monitoring capabilities of the MMU-16LE. Refer to
sections 3.9, 3.2, 3.7, 3.2.1, and 2.5.2 of this manual for further information.
Fault Type
Bit #
Nema Designation
Field Check Fault/Status
67
Spare Bit #1
Dual Indication Fault
68
Spare Bit #2
RP Detection Status
69
Spare Bit #3
External Watchdog Fault
70
Spare Bit #4
Yellow Plus Red Clearance
71
Spare Bit #5