Transas T214, Technical Manual

Page: 69 / 115

Settings of Base Station configuration
Chapter 6. Commissioning.Internal configuration
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4. If configured to be semaphore, the AIS Base Station shall revert to semaphore
behaviour upon detection of semaphore condition on the VDL. The Base Station
shall be capable of using the two methods concurrently.
Epoch planning mode (On/Off)
The “Epoch planning mode” parameter changes the amount of FATDMA schedule
settings. With the “Off” value, the schedule is adjusted in accordance with the CBM
sentence parameters (planning for a period of 1 minute). With the “On” value, the
schedule is set up in accordance with the ECB sentence parameters (planning for a
period of 6 minutes). These sentences can be set up in the Configuration->Setup-
>BS setup->Schedule (CBM/ECB) menu. The window content in the “Schedule”
submenu corresponds to the selected “Epoch planning mode” parameters.
The interval span in this sentence supports FATDMA planning where six-minute
epochs are used. When planning the FATDMA use of VDL slots, time can be
organized into six minute periods identified using FATDMA “epoch numbers” (0 to
9). The start of a FATDMA epoch is correlated with the beginning of the hour. An
FATDMA epoch starts with the first second of the first minute, and ends with the end
of second 59 of the sixth minute of the epoch. The FATDMA epoch number of each
FATDMA epoch in one hour is correlated to an absolute start minute within the hour
(FATDMA epoch number × 6). For example, FATDMA epoch “0” is minute 0 through
5, and FATDMA epoch “9” is minute 54 through 59. The AIS Base Station, upon
receipt of an ECB Query for this information, will generate sentences for all message
types (4, 17, 20, 22, and 23) providing the current broadcast schedule. Even
unscheduled messages need to be reported. New ECB assignments will override
existing CBM or ECB assignments.
СВМ – Configure Base Station Message Broadcast Reporting Rates
This sentence is adjusted in the Configuration->Setup->BS setup->Schedule
(CBM/ECB) menu. The Configuration->Setup->BS setup->Epoch planning mode
parameter should assume the “Of” value».
This sentence configures the broadcast schedule of ITU-R M.1371 messages 4, 17,
20 and 22 that are to be broadcast from an AIS Base Station. It establishes the
broadcast schedule for each frame until changed. The AIS Base Station should
apply the information provided by this sentence to autonomously and continuously
transmit the VDL messages indicated until revised by a new CBM sentence. The
AIS Base Station, upon receipt of a Query for this sentence, will generate this
sentence providing the current broadcast schedule of ITU-R M.1371 messages 4,
17, 20 and 22 to the requestor.
For the description of messages see under (Table 3. AIS Base Station T214
Input/Output Sentences Formatters).
New CBM assignments will override CBM or ECB assignments.
Note: This sentence cannot control message 23 (See ECB sentence).