Victron VE.Direct with Raspberry Pi/Signal K

Updated 2022-01-11 !

During my update of the cables going from the batteries, to the distribution panel and engines, I stumbled over the Victron SmartShunt(VSS). We had a 15 year old Mastervolt battery monitor but it didn't feel "true" and it wasn't at the right place in the boat. So instead of moving the old shunt we bought a VSS. 

Introduction

The VSS don't have any display but can be used, standalone via Bluetooth, with the VictronConnect app which is available for different OS. 

If you want to get the data from VSS via a cable there is a serial VE.Direct(VED) output which can be connected to a 

• Victron GX product running the Victron Venus OS
• Raspberry Pi running Victron Venus OS. Link to install
• Raspberry Pi running Signal K(SK) with the SK server plugin, "@signalk/vedirect-serial-usb", that will do the job translating the data to SK format

My Inspiration link

Cables

To get the serial data, to the SK server, the most straightforward way is to buy the Victron USB interface cable, and connect it to the computer running the Signal K server.

Here we will check out two DIY ways to connect to a Raspberry Pi(RPi) but please note !! that these solutions don't have galvanic isolation as the Victron cables have.

Victron have different products with the VED interface and they have different logic levels. For the VSS it's 3,3 V so it matches the RPi inputs.

Using a "standard" USB to serial console cable you do the connection as follows. The VSS pin numbers are found in the picture above. If you want to validate this cable, check below at Cable check.    

VSS pin	USB cable color
Gnd, 1	GND, Black
TX, 3	RX, White

Another way is to use a "direct cable" connected like this

VSS pin	RPi pin
Gnd, 1	GND, 9
TX, 3	RX, 10

The cable could be a JST PH 4Pin cable.

USB cable

After Connecting the USB cable it will probably appear as "/dev/ttyUSB0". Check with 

dmesg | grep tty

Direct cable

Per default the RX/TX pins, on any Raspberry Pi, are setup as a serial console. This means that you can use the USB console cable, mentioned above, to log on from almost any computer, which have an USB port, to the RPi. We have to disable this function with 

sudo rasp-config

3. Interface options => 

    I6 Serial Port Enable/disable shell messages on serial connection

    

    Would you like a login shell to be accessible over serial? => No

    Would you like the serial port hardware to be enabled? => Yes

    The serial login shell is disabled

    The serial interface is enabled  => OK

Shutdown with "sudo shutdown now", connect the 2 cables, boot up and check with

dmesg | grep tty

probably it will appear as "/dev/ttyS0"

Check the output
In both cases you have to set the port baud rate, matching the output from the VSS, with 

stty -F /dev/ttyXX 19200

the "ttyXX" should be exchanged with what you got above. Then check the data with

cat /dev/ttyXX

and you will see something like

PID 0xA389

V 13515

VS -12

I -453

.........

Send to Signal K
Direct attached VSS

Via the SK Appstore install "@signalk/vedirect-serial-usb" and configure it via "Plugin Config".

Using the SK "Data Browser" check the data.

Remote VSS

In our boat the batteries are in the aft part and the SK server is ahead. So the solution was to place a Raspberry Zero W(RZ), at the VSS, avoiding long cables. The shunts serial output connects, with a "Direct cable", to the serial input on the RZ. 

With "socat"
There are several solutions to send the data from the RZ to the SK server but the solution, with the smalest footprint, is to use "socat" and forward the data via UDP.

Install "socat" with "sudo apt install socat" and test the output from VSS with 

socat /dev/ttyS0,b19200,raw,echo=0,crnl -

Interrupt the command with Ctrl +c and then issue the command 

socat -u /dev/ttyS0,b19200 UDP-SENDTO:zest:8888

where "zest" is the hostname of the target SK server. Configure the plugin on the target SK server to receive UDP at the right port number and check the data in "Data Browser".

If you want this command to be working in the background, autostart at boot and restart if it fails I really recommend using systemd. Check this post and search for "Autostart with systemd" where you get some hints for the setup.

With Signal K
Another way could be to set up a complete SK server on the RZ with the use of the "@signalk/vedirect-serial-usb" plugin. When the RZ is setup it will automagically appear, at the target SK server, where you use that suggestion to set upp the connection.

Please note that Node.js 16 have to be installed via binaries on the RZ. Check below.

This approach could also be used due to that you want to use the embedded NodeRed plugin, on the RZ, where one of the use cases could be to connect an analog to digital converter ADS1115. Check this post where the node "signalk-send-pathvalue" is used.

With Node-Red

With Raspberry Pi OS Lite install Node-Red, "node node-red-node-serialport", "node-red-contrib-ads1x15_i2c" and import this flow.

The flow part with the "ADS 1015" node is from this post.

Cable check

A loopback test will check the mentioned cable. Connect the RX(white) and the TX(green), cable to each other and in a terminal window issue the receive command 

socat /dev/ttyUSB0,b19200,raw,echo=0,crnl -

In another terminal window issue the send command

echo "Test data" > /dev/ttyUSB0

If you receive the text in the listen window you have succeeded and the cable is OK.

This test also applies to testing the "direct" port on the RPi and then doing a connect between between the GPIO pin 9 and 10.

Node.js 16 on Raspberry ZW

Hints .....

https://nodejs.org/dist/

https://nodejs.org/dist/latest-v16.x/

wget https://nodejs.org/dist/latest-v16.x/node-v16.14.0-linux-armv7l.tar.gz

tar -xzf node-v16.14.0-linux-armv7l.tar.gz

node-v16.14.0-linux-armv7l/bin/node -v

v16.14.0

cd node-v16.14.0-linux-armv7l

sudo cp -R * /usr/local/

node -v

npm -v

rm node* -rf