Operations and Maintenance Manual

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JANUS
®
Multi-Protocol Reader Ver. 2: Maintenance Instructions
Confidential UM 360463-202: A12 (Draft) Page 139 of 291
© Kapsch TrafficCom Canada Inc. 2013
These drawings and specifications contain confidential and proprietary information and are the property of Kapsch TrafficCom Canada Inc. and are issued in strict
confidence and will be kept confidential and used solely for the purpose intended and for no other purpose and shall not be transmitted, reproduced, copied, and/or
used as the basis for manufacture or sale of apparatus unless otherwise agreed to in writing by Kapsch TrafficCom Canada Inc.
FILE: MPR2_OPERATIONS_AND_MAINTENANCE-MANUAL_REV A12.DOCX 05/08/2014 11:24
Kapsch TrafficCom
If unsynchronized Readers are located within a 200 meter (660 feet) radius, tests for in-band RF
interference should be carried out to ensure that no Reader-to-Reader interference occurs. This test
should be carried out under live traffic conditions to ensure that RF signal reflections off moving
vehicles do not exceed the in-band limits. If Reader-to-Reader RF interference exceeds the in-band
limits then the Readers must be synchronized.
How Reader synchronization operates at the toll location
After interrogating all of the assigned MRFM-S slots in the rack, each Reader will provide a ‘sync
ready’ signal on its SPM terminal block. Only when the configuration parameter Enable Reader Sync
is set ON for all Readers in the sync network does synchronization occur.
As busy Readers become ready they will not send any more RF trigger signals until the sync bus
indicates that all Readers are ready. Once the last Reader in the network generates its ready signal, all
Readers on the sync bus simultaneously generate OBU trigger pulses starting with the RF module in
slot 1. This can be seen in the truth table shown below for synchronization circuit consisting of two
Readers.
Table 4-2: Boolean Logic Truth Table for Synchronization of two Readers
The truth table above demonstrates the following rule of synchronization operation:
The sync bus will only be in the ready state when all Readers in the group are in the ready state.
The last Reader to acquire a ready state controls the system synchronization. Most of the time (greater
than 95%), the sync bus will be in the busy state. If operating correctly, the sync bus will normally be in
the ready state for about 100 Sec.
The Sync Recovery Process
When a Reader detects it is out of synchronization, it attempts to re-establish synchronization at the
beginning of every superframe. During this time, the CTM SYNC LED flashes green/orange (the orange
is a mix of green and red due to the short amount of time in red).
Note: Connection of other equipment or external synchronization devices is not supported and may
cause Reader errors.
Reader 1 sync port Tx
Reader 2 sync port Tx
Reader 1 or 2 sync port Rx
0 (ready)
0 (ready)
0 (ready)
0 (ready)
1 (busy)
1 (busy)
1 (busy)
0 (ready)
1 (busy)
1 (busy)
1 (busy)
1 (busy)