pdjr-skplugin-venus-tanks

This plugin is intended for Signal K servers running on Venus OS.

pdjr-skplugin-venus-tanks represents Signal K tanks as D-Bus services, injecting tank data from Signal K into Venus OS and enabling its display on the Venus GUI.

This is useful because it provides a work-around for Venus' broken native support for CAN connected multi-channel tank sensor devices like the Maretron FPM100 and the Garnet SeeLevel.

Although designed to address Venus' problem with multi-channel tank sensors, the project will, of course, inject any Signal K tank data into Venus and so make it available to devices like the CCGX.

The plugin borrows GUI enhancements from Kevin Windrem's tank repeater project to achieve the display shown below. Of course, you can also roll your own GUI for tank data rendering.

Background

Support for tank monitoring in Venus OS is fundamentally broken. The OS code implementing 'socketcan' services assumes one tank sensor device per physical tank and generates a single D-Bus tank service for each sensor device based on this false understanding.

Consequently, a tank service in Venus that represesents a multi-channel tank sensor device is chaotically updated with data from all the tank sensors that are connected to the multi-channel device resulting in a GUI rendering of the data that is unintelligible.

Somewhere in this broken-ness Venus discards tank sensor instance numbers making disaggregation of the garbled composite data at best problematic and, for non-trivial tank installations, infeasible.

Even so, there have been a number of attempts at implementing fixes and work-arounds based on the timing of fluid type and tank level data updates but these do not allow disambiguation in installations which have more than one tank of a particular fluid type.

If you have a multi-channel tank sensor on CAN and you have only one tank of each fluid type, then look at Kevin Windrem's project (see above) for a solution that doesn't involve Signal K.

System requirements

A Venus OS based host system running Signal K and configured to display Venus' 'boat and motorhome overview'.

You can enable and disable 'boat & motorhome overview' by navigating to MENU -> Settings -> Display & language -> Show boat & motorhome overview on your Venus OS GUI.

If you require similar functionality but do not run Signal K under Venus or you prefer to maintain D-Bus tank data with a native Venus process, then consider using this alternative Python application.

Installation

Download and install pdjr-skplugin-venus-tanks using the Appstore link in your Signal K Node server console. The plugin can also be obtained from the project homepage and installed using these instructions.

Configuration

pdjr-skplugin-venus-tanks does not require configuration: all that is necessary after installation is a restart of your Signal K server.

By default the plugin will enable some tweaks to the 'boat & motorhome' view of your Venus host's GUI and create D-Bus tank services for every tank reported within Signal K. If you need to change either of these behaviours, then:

1. Login to your Signal K dashboard and navigate to Server->Plugin Config->Venus tanks interface and select the Configure button to open the configuration panel and reveal the following options.

2. OPTION: "Use GUI enhancements?"

   This option is checked by default and tells the plugin that it should use this project's versions of OverviewMobile.qml and TileTank.qml rather than the system's currently installed versions.

   To achieve this the plugin will backup the existing versions of these files and install its enhanced versions in their place. The GUI changes implemented by the two .qml files prevent the native display of CAN derived tank data and adjust the 'mobile' display page to better accommodate the display of multiple tank entries.

   Unchecking this option will prevent the use of the plugin's enhanced GUI, if necessary reverting any system changes that may have been made previously by restoring the backed up .qml files.

3. OPTION: "Tanks"

   This array option is empty by default, telling pdjr-skplugin-venus-tanks to create a D-Bus service for every tank reported in Signal K.

   If you want the plugin to support just specific tanks or you need to adjust the tank capacity value reported by Signal K for one or more tanks then you must configure each tank explicitly by adding entries to the Tanks list, one for each tank you want the plugin to process.

   Each tank entry consists of path and factor settings.

   path specifies the Signal K tank path of the tank being configured and must be of the form 'tanks.fluid-type.tank-instance'.

   factor must be a decimal value greater than or equal to 0.0 (it defaults to 1.0). This feature is useful when individual tank sensor monitors are poorly configured or report in non-standard ways: some perhaps returning volume in litres, others in cubic-metres. Venus OS expects tank capacity to be reported in litres.

4. When you have made any changes you require, click Submit to save your choices and start the plugin.

5. Reboot your Venus host or login and restart the GUI:

   $> svc -d /service/gui
   $> svc -u /service/gui
   

Reviewing operation in Venus OS

Once the plugin is installed, configured and working you can log into your Venus host and check things out.

On my five-tank system, for example:

$> dbus-spy
Services
com.victronenergy.battery.ttyO2                              BMV-700
com.victronenergy.fronius
com.victronenergy.logger
com.victronenergy.modbustcp
com.victronenergy.qwacs
com.victronenergy.settings
com.victronenergy.system
com.victronenergy.tank.signalk_192_168_1_2_3000_0_3          SignalK tank interface
com.victronenergy.tank.signalk_192_168_1_2_3000_0_4          SignalK tank interface
com.victronenergy.tank.signalk_192_168_1_2_3000_1_1          SignalK tank interface
com.victronenergy.tank.signalk_192_168_1_2_3000_1_2          SignalK tank interface
com.victronenergy.tank.signalk_192_168_1_2_3000_5_0          SignalK tank interface
com.victronenergy.tank.socketcan_can0_vi0_uc1640899          Tank sensor
com.victronenergy.vebus.ttyO1                                Quattro 24/8000/200-2x100
com.victronenergy.vecan.can0

If you choose one of the tank services you will be able to see tank data updates as they occur. For example.

com.victronenergy.tank.signalk_192_168_1_2_3000_0_3
Capacity                                                                     1.7981
Connected                                                                         1
DeviceInstance                                                                    3
FirmwareVersion                                                                   0
FluidType                                                                         0
HardwareVersion                                                                   0
Level                                                                        89.104
Mgmt/Connection                                                      SignalK tank:3
Mgmt/ProcessName                                              SignalkTankService.js
Mgmt/ProcessVersion                                                           1.0.0
ProductId                                                                         0
ProductName                                                  SignalK tank interface
Remaining                                                                   1.60218

You can see that my port-side fuel tank is reporting capacity in cubic-metres: I should really adjust this to litres in some way; maybe by setting a multiplication factor of 1000.0 for this tank.

Acknowledgements

Thanks to @kwindrem for making this a whole lot easier than it might have been by designing his repeater software in a way which allows its components to be leveraged by others.

Thanks to @mvader at Victron for his support and encouragement and for inviting me to think about a Signal K plugin variant of venus-signalk-tank-handler.

Author

Paul Reeve <preeve@pdjr.eu>