Introduction

The NM-251D-INC is a member of the NM-251 Series family and is programmed to function as an Inclinometer Sensor data output format converter in order to display the Trim and List Values transmitted to the Furuno RD-33 display.

In addition the NM-251D-INC supplies optical isolation to the interfaced systems (RS232 sensor output and the RD-33) as required by the NMEA-0183 protocol.

Operation

The NM-251D-INC acquires the RS-232 serial signal input port only. The NM-251D-INC extracts the values for the trim and list angles transmitted from the sensor and create a compatible NMEA-0183 string as shown below:

The new NMEA-0183 string is then transmitted to all five RS-422 output ports and the RS-232.

Input Ports (listeners)

The NM-251D-INC uses one of the two input ports. The input port Inb is not available at the NM-251D-INC custom interface and should not be connected. The listener port Ina is optically isolated. Since the inclinometer sensors’ talker port is single ended, the signal wire (hot) should be connected to the Ina(+) input terminal and the Ina(-) should be tide to sensor’s ground (see typical application drawing below). The listener port Ina can acquire signals carried in TTL, RS-232 and RS-485/422 signal levels.

Installation and operation manual