Garmin GHP 12 Autopilot System Installation Instructions - Page 21

6. When the drive-unit speed is tuned correctly, select Done. Tuning the Error Tolerance on a non-Garmin Drive-Unit The error tolerance of the drive unit determines how much error the autopilot allows before adjusting the drive unit. If you set the error tolerance too low, the drive unit will react to the slightest course deviation. This causes the drive to work harder and may drain your battery at a faster-than-normal speed. If you set the error tolerance too high, the drive unit will not react until your course is off a significant distance. This causes a less reliable heading hold, and can result in unnecessarily large course corrections. 1. From the Heading screen, select Menu > Setup > Dealer Autopilot Configuration > Steering System Setup > Drive Unit Type. 2. Select Other or Solenoid, according to what you set in the dockside wizard. 3. Select Advanced Tuning > Tune Error Tolerance. 4. Center the rudder position, let go of the rudder control, and select Begin. 5. Select Tune. The rudder position moves from +5° to -5° each time you select Tune, and the drive unit steers and holds the rudder accordingly. 6. After the drive unit stops, observe the rudder error and power usage fields for 30 seconds. • If the power usage field fluctuates, then your error tolerance is set too low. • If the power usage field stays at 0%, but the rudder error field shows and unacceptable degree of error (1% or more), then your error tolerance is set too high. TIP: An ideal error tolerance configuration holds the rudder at an acceptable degree of error (.5% or so) without unnecessarily adjusting the drive unit and wasting power (0% for 30 seconds or more). 7. If necessary, select Adjust. 8. Select an option: • Decrease the value if the error tolerance is too high, and repeat steps 3-5. • Increase the value if the error tolerance is set too low, and repeat steps 3-5. 9. When the drive-unit error tolerance is tuned correctly, select Back. Appendix NMEA 0183 Wiring Diagrams The following three wiring diagrams are examples of different situations you may encounter when wiring your NMEA 0183 device to the GHC 20. Example One of Three - Two-way NMEA 0183 Communication ➋ ➌ + - ➊ ➊ > > ➌ ➋ > ➍ > ➍ > > ➎ > > ➏ ➊ GHC 20 ➋ NMEA 2000 network (provides power to the GHC 20) ➌ 12 Vdc power source ➍ NMEA 0183-compatible device Wire GHC 20 Wire Color - Function N/A N/A Blue - Tx/A (+) White - Tx/B (-) Brown - Rx/A (+) Green - Rx/B (-) NMEA 0183-Compatible Device Wire Function Power NMEA 0183 ground Rx/A (+) Rx/B (-) Tx/A (+) Tx/B (-) NOTE: When connecting NMEA 0183 devices with two transmitting and two receiving lines, it is not necessary for the NMEA 2000 bus and the NMEA 0183 device to connect to a common ground. GHP 12 Installation Instructions 21