I installed a digiflight 11vs in my RV7A. I can't get the autopilot to go into nav mode. I have followed the TruTrak instrutions for a GX65 and tried all the setup combinations for pin 5 and pin 22. The GX and the Autopilot are communicating but the autopilot will not go into the nav mode. Anyone know what I'm doing wrong or not doing. Thanks
Van's Air Force
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TruTrak Autopilot
- Thread starter casper
- Start date
GPS Nav Mode vs GPS Steering
So on TruTrak's site (http://www.trutrakflightsystems.com/autopilot2_2.htm), it says that the DigiFlight II-VS has GPS Nav Mode, but not GPS Steering.
The FAQ on TruTrak's site has this to say:
Q - What is GPS Nav?
A - GPS Nav is similar to GPS Steering but not as sophisticated. GPS Nav signals are on the RS-232 output (GPRMC and GPRMB sentence in the data string) from most GPS's. This is the same RS-232 connection that is required for the autopilot to be functional so no additional wiring is necessary. Virtually all GPS's (handhelds included) have the output that is required for GPS Nav. GPS Nav flies a preprogrammed route with multiple waypoints. The course intercept feature of GPS Nav allows the autopilot to seamlessly intercept courses regardless of the aircraft's initial direction of flight. When the last waypoint is flown over the autopilot reverts to the track mode. All Trutrak autopilots have GPS Nav Mode.
Q - What is GPS Steering?
A - GPS Steering is a new way to fly a flight plan that is programmed into a GPS. Some GPS's have the required output for GPS Steering. With GPS Steering the GPS calculates a desired bank angle for the autopilot to fly. There is no overshoot of the desired course in any course change. GPS Steering allows the Trutrak family of autopilots to fly complex patterns such as holding patterns and DME arcs with stunning precision
Q - What is the difference between GPS Steering and GPS Nav?
A - GPS Nav does not anticipate a course change. Thus when one leg is finished the autopilot has to intercept the next leg after over flying the waypoint. With GPS Steering the autopilot does not have to intercept the new leg because it starts intercepting procedure before reaching the waypoint so that when the intercept turn is complete the aircraft will be on the next leg. GPS Steering will also fly complex turns such as DME arcs and holding patterns. If you want the increased capability of GPS Steering you must be sure that your GPS supports GPS Steering.
Q - Which GPS systems provide the GPS Steering signal required for GPS steering?
A - Most panel GPS that are IFR certified Garmin 250/300XL, Garmin GNC 430/530, 480, Apollo GX50/55/60/65 and, King KLN 90/90B, Sierra Flight Systems, Chelton Flight System, and Grand Rapids EFIS. In most cases the signal used for GPS Steering is the ARINC 429 Roll Steering signal, however the Apollo GX50/55/60/65 units provide GPS Steering over the RS-232 line.
So with all that said. I think your set up should work Doyle. It just needs 'something' adjusted. Maybe the GX65 is sending GPS-Steering info and it needs to just be sending GPS-Nav info since the DigiFlight II-VS can only understand the GPS-Nav. Is there such a thing?
-Jim
RV-10 40603, wings
So on TruTrak's site (http://www.trutrakflightsystems.com/autopilot2_2.htm), it says that the DigiFlight II-VS has GPS Nav Mode, but not GPS Steering.
The FAQ on TruTrak's site has this to say:
Q - What is GPS Nav?
A - GPS Nav is similar to GPS Steering but not as sophisticated. GPS Nav signals are on the RS-232 output (GPRMC and GPRMB sentence in the data string) from most GPS's. This is the same RS-232 connection that is required for the autopilot to be functional so no additional wiring is necessary. Virtually all GPS's (handhelds included) have the output that is required for GPS Nav. GPS Nav flies a preprogrammed route with multiple waypoints. The course intercept feature of GPS Nav allows the autopilot to seamlessly intercept courses regardless of the aircraft's initial direction of flight. When the last waypoint is flown over the autopilot reverts to the track mode. All Trutrak autopilots have GPS Nav Mode.
Q - What is GPS Steering?
A - GPS Steering is a new way to fly a flight plan that is programmed into a GPS. Some GPS's have the required output for GPS Steering. With GPS Steering the GPS calculates a desired bank angle for the autopilot to fly. There is no overshoot of the desired course in any course change. GPS Steering allows the Trutrak family of autopilots to fly complex patterns such as holding patterns and DME arcs with stunning precision
Q - What is the difference between GPS Steering and GPS Nav?
A - GPS Nav does not anticipate a course change. Thus when one leg is finished the autopilot has to intercept the next leg after over flying the waypoint. With GPS Steering the autopilot does not have to intercept the new leg because it starts intercepting procedure before reaching the waypoint so that when the intercept turn is complete the aircraft will be on the next leg. GPS Steering will also fly complex turns such as DME arcs and holding patterns. If you want the increased capability of GPS Steering you must be sure that your GPS supports GPS Steering.
Q - Which GPS systems provide the GPS Steering signal required for GPS steering?
A - Most panel GPS that are IFR certified Garmin 250/300XL, Garmin GNC 430/530, 480, Apollo GX50/55/60/65 and, King KLN 90/90B, Sierra Flight Systems, Chelton Flight System, and Grand Rapids EFIS. In most cases the signal used for GPS Steering is the ARINC 429 Roll Steering signal, however the Apollo GX50/55/60/65 units provide GPS Steering over the RS-232 line.
So with all that said. I think your set up should work Doyle. It just needs 'something' adjusted. Maybe the GX65 is sending GPS-Steering info and it needs to just be sending GPS-Nav info since the DigiFlight II-VS can only understand the GPS-Nav. Is there such a thing?
-Jim
RV-10 40603, wings
