The NM-281A is a two channel NMEA-0183 input / seven or eight channels NMEA-0183 output multiplier. It enables data distribution from two NM-0183 sources (primary and secondary with priority encoding) to all NMEA-0183 instruments through seven or eight talker ports and PC connection through RS-232. In addition the NM-281A has control terminals that can be connected to a two position external switch to force connection of the first or second input to all outputs. Data from PC’s charting system can be delivered back to the autopilot from the same RS-232 port which acts bidirectional (talker and listener).
In the case that automatic operation is enabled (external switch disconnected or at position “0”, see figures 1-3), the NM-281A acquires NMEA-0183 sentences from the most significant input and immediately sends them to the general purpose outputs and the RS-232. A watchdog timer routine supervises if the NMEA signals are correctly applied in the primary input and switches to the secondary input whenever there is no NMEA sentence for at least eight seconds. In this case the secondary input starts receiving data if there is an instrument attached. If not, the device automatically returns to the primary input after eight seconds. When the secondary input is already in receiving mode and an NMEA signal is applied to the primary port, the device immediately switches to the primary input. In the case that no signal is applied to any input, the device “circles” around sampling the two listener ports every eight seconds until an NMEA-0183 signal appears to any of the two listener ports. In the case that an external switch is connected (see figures 1-3), the NM-281A outputs the signals from the first input if switch is at position “1” or signals from the second input if switch is at position “2”.
- NM281 Installation & Operation manual
Price 220.00 EURO
VAT not included
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