Data from EV-1

[Chuck - Raymarine - Moderator]

Keith,

Q1. What does "only when underway" in your sentence apply to? And how does the EV-1 know that the vessel is underway?
A1. The physical design of the EV-1 sensor core include not only magnetometer, but also gyro and accelerometer sensors. According, heading is sensed by magnetometer, is stabilized by the gyro. Rate of turn, pitch, and roll are additionally sensed by the gyros, although only roll (Heel Angle) and Rate of Turn data items are able to be displayed within the system. The statement referenced previously which included underway should have stated underway and making way, as motion sensed by the accelerometers will trigger the Evolution autopilots to then display a "virtual" rudder angle (rudder bar) when should the autopilot not be fitted with a rudder reference transducer. Should the autopilot be fitted with a rudder reference transducer, then the autopilot control head will be capable of displaying rudder angle irrespective of whether the vessel is stationary or making way.

Q2. Related, that same pdf says that the EV-1 also receives 127250 "Vessel heading" - how is this used?
A2. Contrary to the pdf, the Evolution Autopilots are exclusively designed to utilize heading data from an EV-1 Sensor Core. While heading data from other sources may be displayed on within the databoxes, databar, etc. of products such as MFD, instrument displays, etc., the Evolution Autopilots will exclusively display heading data from the EV-1 Sensor Core.

Q3. In my application I have two devices transmitting 127250 - the EV-1 and an Airmar WS-200WX, but only the EV-1 is showing up in my a78 as a source for "Heading". The a78 is receiving wind data from the Airmar (and the EV-1 can receive wind data PGNs), but apparently not heading from the Airmar. And a laptop on this network is receiving 127250 from both devices. Is there some particular filtering that the a78 is doing to discard the Airmar's 127250 PGN?

A3. It is possible that in systems featuring an EV-1 Sensor Core the system will ignore other NMEA 2000 sources of heading data, as a single source of each type of data may only be used within the system or unpredictable results may occur. This may be verified by unplugging the EV-1 Sensor Core from the backbone, powering the system ON, and then determining whether the Data Sources feature lists the WS-200WX The one exception to this, only recently surfaced, is heading from a NMEA 0183 source. In the case of the latter, the a/c/e/eS/gS-Series MFD's auto selection feature appears to select the NMEA 0183 heading source for all devices except for the EV-1 Sensor Core.