> For the complete documentation index, see [llms.txt](https://spascual90.gitbook.io/fenix-autopilot/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://spascual90.gitbook.io/fenix-autopilot/using-fenix-tiller-pilot/untitled.md). # Serial Interface ## Introduction Fenix Autopilot can be connected to a Laptop/PC via USB port. This provides access to all user functions available to calibrate compass and linear actuator. Also provides full capabilities to customize installation settings and pilot gain. ## Requirements * Serial Terminal shall be installed to Laptop/PC to communicate with Autopilot to use Serial Interface (eg. Arduino IDE, Putty) * [Checksum calculator](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#checksum) * [$PMEC Message specification](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#usdpemc-message) in this Guide. ### Checksum In order to generate $PEMC messages to be accepted by Fenix Autopilot, a checksum code shall be annexed after \* symbol. {% hint style="info" %} Serial I/F examples in this User Guide represent Checksum code as `xx`. To use these examples you should substitute `xx` by the calculated Checksum value. `Serial I/F Example: $PEMC,00*xx` `Serial I/F Valid Sentence: $PEMC,00*37` {% endhint %} In this link you will find an online Checksum calculator {% embed url="" %} {% embed url="" %} #### Set messages: 04 and 06 To keep same value of a parameter while changing others, omit any value while keeping the commas in place. {% hint style="info" %} To set Ki value while keeping Kp and Kd: $PEMC,06,,0.3,,,m\*xx {% endhint %} {% hint style="warning" %} Fenix V0.1 bug: Message 06, always include `m, M or A` deadband value or system will change to `M`. {% endhint %} ### $PEMC Message | Field | Value | Function | Additional Field | Sentence | | ----- | ----- | --------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------- | | 1 | 00 | Switch working mode from STAND BY to AUTO | N/A | $PEMC,00\*37 | | 1 | 01 | Change Current Rudder | [2: Change rate](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#additional-field-change-rate) | $PEMC,01,r\*68 | | 1 | 02 | Change CTS (Current Target Steering) | [2: Change rate](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#additional-field-change-rate) | $PEMC,02,i\*70 | | 1 | 03 | Get Installation Parameters | [2: Installation Parameters](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#additional-field-installation-parameters) | $PEMC,03,2,45,5,S,2,-3.2,-32.9,10\*xx | | 1 | 04 | Set Installation Parameters | [2: Installation Parameters](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#additional-field-installation-parameters) | $PEMC,04,2,40,4,S,3,4.1,33.9,9\*xx | | 1 | 05 | Get PID gain (incl. sample time and deadband) | [2: PID Gain](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#additional-field-pid-gain) | $PEMC,05,2,0.01,0.5,100,A\*xx | | 1 | 06 | Set PID gain (inc. sample time and deadband) | [2: PID Gain](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#additional-field-pid-gain) | $PEMC,06,3,0.11,0.7,100,m\*xx | | 1 | 07 | Get Autopilot information | [2: APinfo](/fenix-autopilot/using-fenix-tiller-pilot/untitled.md#additional-field-apinfo) | $PEMC,07,S,12,35.60,30.02,2,-0.50\*65 | | 1 | 08 | Request information |

2: 'I' Request Installation Parameters (message $PEMC,03)

2: 'G' Request Gain (message $PEMC,05)

2: 'A' Request Autopilot info. (message $PEMC,07)

|

$PEMC,08,I*5A

$PEMC,08,G*54

$PEMC,08,A\*52

| | 1 | 09 | Enter/ Exit into IMU Calibration mode |

2:'-' Calibration of all sensors in sequence 2:'G' Gyroscope calibration only

2:'A' Accelerometer calibration only

2:'M' Magnetometer calibration only

|

$PEMC,09,-*xx

$PEMC,09,G*xx

$PEMC,09,A*xx

$PEMC,09,M*xx

| | 1 | 10 | Enter/ Exit Feedback Calibration mode | N/A | $PEMC,10\*36 | | 1 | 11 | Save values |

2: 'I' Save Installation and current Feedback Parameters

2: 'G' Save current PID Gain parameters

2: 'C' Save current IMU Offsets

2: 'R' Restore Inst.Param, Feedback and PID Gain to hardcoded values

|

$PEMC,11,I*52

$PEMC,11,G*5C

$PEMC,11,C*58

$PEMC,11,R*49

| | 1 | 12 | IMU Cal.Mode status | Cal.Mode values | $PEMC,12, | #### Additional Field: Change rate [![](https://firebasestorage.googleapis.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M1IFMsiQH0N5uEseRXb%2Fuploads%2FacmjKiNZvOmCvT3sdMR1%2Ffile.gif?alt=media)](https://emacua.fandom.com/wiki/System_Interfaces?action=edit\§ion=9) | Field | Value | Function | Additional Field | | ----- | ----- | ------------------------------------- | ---------------- | | n | 'i' | Increment Current by 1 Position Unit | N/A | | n | 'I' | Increment Current by 10 Position Unit | N/A | | n | 'r' | Reduce Current by 1 Position Unit | N/A | | n | 'R' | Reduce Current by 10 Position Uni | N/A | #### Additional Field: Installation Parameters [![](https://firebasestorage.googleapis.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M1IFMsiQH0N5uEseRXb%2Fuploads%2FfOfMRFSx9Pu5ReJekINY%2Ffile.gif?alt=media)](https://emacua.fandom.com/wiki/System_Interfaces?action=edit\§ion=10) | Field | Value | Function | Additional Field | | ----- | ------------ | ---------------------------- | ---------------- | | n | Integer | Centered Tiller Position | N/A | | n+1 | Positive Int | Maximum rudder angle | N/A | | n+2 | Positive Int | Average Cruise Speed | N/A | | n+3 | 'S' | Installation Side: Starboard | N/A | | n+3 | 'P' | Installation Side: Portboard | N/A | | n+4 | Positive Int | Rudder Damping | N/A | | n+5 | Float | Magnetic Variation | N/A | | n+6 | Float | Heading Alignment | N/A | | n+7 | Positive Int | Off course alarm angle | N/A | #### Additional Field: PID Gain [![](https://firebasestorage.googleapis.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M1IFMsiQH0N5uEseRXb%2Fuploads%2Fq2R7cAPb2cDKJIdSPnwG%2Ffile.gif?alt=media)](https://emacua.fandom.com/wiki/System_Interfaces?action=edit\§ion=11) | Field | Value | Function | Additional Field | | ----- | ------------- | ------------------ | ---------------- | | n | Float | Kp | N/A | | n+1 | Float | Ki | N/A | | n+2 | Float | Kd | N/A | | n+3 | unsigned long | Sample Time (mSec) | N/A | | n+4 | 'm' | Deadband: Min | N/A | | n+4 | 'M' | Deadband: Max | N/A | | n+4 | 'A' | Deadband: Auto | N/A | #### Additional Field: APinfo [![](https://firebasestorage.googleapis.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M1IFMsiQH0N5uEseRXb%2Fuploads%2FC0vHPcXOrfRFakN9kyMY%2Ffile.gif?alt=media)](https://emacua.fandom.com/wiki/System_Interfaces?action=edit\§ion=12) | Field | Value | Function | Additional Field | | ----- | ------------ | -------------------------------------- | ---------------- | | n | 'S' | STAND-BY Mode | N/A | | n | 'A' | AUTO Mode | N/A | | n | 'T' | TRACK Mode | N/A | | n | 'C' | Calibration Mode (IMU or Feedback) | N/A | | n+1 | Integer | Current Rudder | N/A | | n+2 | Float | Heading Magnetic (HDM) - Magnitude (M) | N/A | | n+3 | Float | Course To Steer (CTS) - Magnitude (M) | N/A | | n+4 | Positive int | Deadband value | N/A | | n+5 | Float | Trimming value | N/A | #### Additional Field: IMU Cal. values [![](https://firebasestorage.googleapis.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M1IFMsiQH0N5uEseRXb%2Fuploads%2Fq3Nzt2jzMSVFIUKTf19q%2Ffile.gif?alt=media)](https://emacua.fandom.com/wiki/System_Interfaces?action=edit\§ion=12) | Field | Value | Function | Additional Field | | ----- | --------------- | ------------------------------------------------------------ | ---------------- | | n | '-' | Calib. Not started | N/A | | n | 'O' | Calib. Ongoing | N/A | | n | 'R' | Recalibrated | N/A | | n | 'N' | Not calibrated | N/A | | n | 'C' | Check ongoing | N/A | | n+1 | 1:OK/ 0:NOK | Sys status. Ony valid when Calib is ongoing | N/A | | n+2 | 1:OK/ 0:NOK | Gyro status. Ony valid when Calib is ongoing | N/A | | n+3 | 1:OK/ 0:NOK | Accel status. Ony valid when Calib is ongoing | N/A | | n+4 | 1:OK/ 0:NOK | Magn status. Ony valid when Calib is ongoing | N/A | | n+5 | Int (0, 360) |

X euler angle.

Ony valid when Check is ongoing

| N/A | | n+6 | Int (-180, 180) |

Y euler angle.

Ony valid when Check is ongoing

| N/A | | n+7 | Int (0, 90) |

Z euler angle.

Ony valid when Check is ongoing

| N/A | | | | | | | | | | | #### Additional Field: IMU Cal. values [![](https://firebasestorage.googleapis.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M1IFMsiQH0N5uEseRXb%2Fuploads%2Fxziw9SatxmPw0FJi7bue%2Ffile.gif?alt=media)](https://emacua.fandom.com/wiki/System_Interfaces?action=edit\§ion=12) | Field | Value | Function | Additional Field | | ----- | ----- | ------------------ | ---------------- | | n | '-' | Calib. Not started | N/A | | n | | | | ## OpenCPN NMEA I/F OpenCPN integrates GPS and plotter capabilities to provide user with all required means to define a route and send it to Fenix Autopilot. OpenCPN is required for Nav mode. Fenix and OpenCPN implements NMEA I/F in both directions ### Data sent by OpenCPN to Fenix Autopilot in ALL working modes from different sources: * **External Compass (only in External Compass mode):** > Message: $HDM - Heading Magnetic {% hint style="warning" %} Features below are not available in V2.x {% endhint %} * **Windvane and calculations** * **GPS Fix** * **Speed Log** ### Data sent by OpenCPN to Fenix Autopilot in NAV Mode: #### Message: $APB - Autopilot Sentence "B" * **Route** * Waypoint ID * Course To Steer to Next Waypoint (CTS) - Magnetic angle * Cross Track Error (XTE) * Arrival Circle Alarm * Perpendicular Circle Alarm {% hint style="warning" %} Feature available with limitations in V0.1: Only APB message decoded. {% endhint %} ### Data sent from Fenix Autopilot to OpenCPN in ALL working modes: #### **Internal compass (in Internal Compass Mode only):** > Message: $HDM - Heading Magnetic > > Message: $HDT - Heading True #### **Rudder position** > Message: $RSA - Rudder Sensor Angle --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://spascual90.gitbook.io/fenix-autopilot/using-fenix-tiller-pilot/untitled.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.