How to Connect Devices to the RV-C Network
The diagram below outlines the basic RV-C network layout. The Firefly Gx panel has a 12 volt power supply feed and this is where the switching and dimming takes place for the lights (or other devices) as shown to the left of the diagram. The right of the diagram shows the RV-C network. The blue line is the main Trunk, note the ‘T’ at each end of the trunk indicating a 120 ohm termination resistor. There are only 2 terminations allowed per network, one is located at each end of the Trunk cable. The green lines are Drops, these connect to wall switches, shade controllers, tank level sensors and whatever other RV-C devices are in the network. Drop cables must not be terminated and are technically limited to about 6′ in length.
Not shown in the diagram above are Drop Taps – these will be located where the green Drop cables meet the blue Trunk. Connecting eRVin (a RaspberryPi with an RV-C compatible “CAN” board) or any other RV-C device to the network can be at any location with a Drop Tap.
The Drop Tap shown below is over the entry door. The two green cables are Drops, The orange connector at the bottom connects to the Trunk. This Drop Tap has 4 Drop sockets, only two of which are being used. This Drop Tap also happens to be at the forward end of the trunk, so is a version with a terminating resistor built in.
On my Entegra Aspire, taps can be found in the following locations:
Behind the panel above the entry door, this is a wider view of the drop tap shown above.
The under the bed tap is a “Common Drop Tap” and has no termination resistor. Also it placement is unusual and not entirely “legal” because it is not connected directly to the Trunk and is being used to create a Drop from another Drop cable.
On the front of the G6 panel in the half bathroom (labeled “Network” port).
On the back of the G6 panel there are several more open connections. On my Aspire there were 12 sockets total and 7 of those were open. Note the termination resistor at the bottom left of the photo – there are three more empty drop sockets behind it.
Normally the easiest place to plug in your eRVin system is to the Net Port on the front of the Gx panel. Keep in mind you want it in a location that will ensure even WiFi reception throughout your rig. Also it is best to keep it in an area not subject to temperature extremes such as over the entry door. Other devices such as with the SeeLevel upgrade will most likely plug in directly to the back of the Gx panel.
Thank you for this website! For a long time, eRVin is something I have been looking for. I have a Tiffin Wayfarer, with the Spyder and Firefly systems. At this time I have a couple of questions: 1) Can you connect to the AirXCel system in the absence of the Aqua-Hot module; and 2) Can you give an example of integration with temperature and humidity sensors? Thank you.
Hi Elliott, eRVin doesn’t directly support Tiffin at this time although you can certainly adapt it to do so. You may be better off with the open source version of coachproxy which directly supports Tiffin models at least up to 2019. eRVin has many updates vs coachproxy, like GPS support and easier access, but right now it doesn’t support any HVAC directly. 1) for airxcel the 1 or 2 wire proprietary communications between the thermostat and the roof units needs to be reverse engineered. This shouldn’t be too difficult but I haven’t been able to get around to it. MicroAir, makers of the Easy Touch thermostat, have already reverse engineered it so I have just been using an EasyTouch for now. 2) Probably the easiest way for temp humidity, battery, etc. sensing is with an ESP8266 or ESP32 device and use MQTT to publish the data where it can be easily integrated with the dashboard via node-red. I have started looking into building my own inexpensive RV-C nodes that could broadcast directly to the RV-C with data on the defined PGN’s, but don’t even have a prototype yet. The ESP modules are really cheap. Let me know if you have any more questions.
Thanks so much for the quick and detailed response. I will take a look at the open source version, but I definitely like your modifications to it. Presently, for remote temperature and humidity sensors, I have set up a Hubitat hub (www.hubitat.com), which, if you are not familiar with it, is capable of handling Z-wave and Zigbee devices. By the way I have installed your image file on an RPi and it is working fine. I thought I would play around with it, before deciding to buy the extra hardware (R-CAN) to interface. One thing I am curious about is that in the coachproxy/configurator folder there is a file “features.json” that has a long list of RV models, including the 2018 Wayfarer. Can this information somehow be used with your version of the OS?
I really like this layout of your web pages what do I need to do to get a configuration file for a Tiffin Bus? I loaded the image all i see is an Entegra not a Tiffin. This RPI shows Raspberry Pi 3 Model B Plus Rev 1.3 Raspbian GNU/Linux 10 (buster) so I think the image is loaded correctly
David, sorry I don’t have configurations for Tiffin (or any other brand except where owners have contributed their efforts). Honestly i can’t even keep up with the Entegra models.
Your best bet is to join the CoachProxy Facebook group or visit the Coachproxy Github page and get the open source version of CoachProxy. I think ooen source CP supports up to 2019 Tiffins but I hear most stuff will work even in the years beyond that. Unfortunately CP will not have any of the extensive upgrades, or ease of access I’ve made to eRVin. I have been thinking about a possible way to add some Tiffin images to eRVin, but that will require some participation from a Tiffin owner. If you are interested in trying this let me know.
I’m just about to wrap up outfitting our Allegro BUs for our next road trip starting in March. I have a version of Coach Proxy working however I want to shift over to your interface for ease of upgrades and hardware changes. Sold my house so this is the next best thing to home automation. I would like to work with you to begin the process of making the changes required.
Please reach out to my email address PS you would really like the network rack installed in this coach I’ll send you photo if interested.
Will this also integrate with Truma heaters?
In order for eRVin to support it, it would need to be capable of connecting to a non-proprietary network, preferably RV-C CAN, but there are other possibilities. I did a brief search and didn’t turn up any info regarding Truma support for the RV-C CAN. But I did notice Tiffin is using some of the Truma devices and they are heavily into RV-C so – maybe? However, even if it had an RV-C network connection, eRVin as it is currently wouldn’t support it, but it probably wouldn’t be too difficult to add at least some of the functions to the eRVin dashboard. If you have any info regarding RV-C support let me know.
Thank you for your prompt response. Truma has a proprietary connection between the heater and its display controller. Its a rj12 connection.
It also intergrates with Firefly systems and others like you mentioned.
I will mentioned that i did purchase a LIN bus encoder/decoder so that I can further “learn” its communication, but I can see its going beyond my head at this point. I was able to communicate with this LIN bus, but have not gone any further.
I wonder if this LIN bus is just another name for rv-c communication.
This is my last piece of the puzzle to integrate with HOME ASSISTANT. I was able to accomplish all different aspects to make this class b sprinter “smart” except for this TRUMA. From lights, holding tank gauges, Victron battery system, water transferring system, and much more.
I will continue researching and provide you with additional info if it will help come up with a resolution.
So far, firefly systems , caracontrol (EU) , and now Tiffin proprietary systems can intergrate with TRUMA heating systems.
Thank you so much for you time,
Hi John, just wanted to say I‘m in the same boat. HA, Firefly, Truma, etc. Possibly we can share some information, though I am just starting. E.g. Victron VE.direct to HA.
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