RV-C

##RV-C: Support library to extend NMEA2000 with addition of RV-C

This library extends the capability of Tim Lappaliainen's NMEA2000 (http: https://github.com/ttlappalainen/NMEA2000) with PGNs for RV-C

You will also need the appropriate underlying hardware CAN libraries, reference NMEA2000 above for details.

RV-C is an industry standard open-source CAN protocol: http://rv-c.com, RV-C specification PDF

Like NMEA2000, RV-C is built upon the J1939 standard in a non-exclusive manner.

DERIVATIONS FROM RV-C SPECIFICATION.

Every attempt has been made to align OSEnergy with the RV-C specification, however as development continues areas have been identified which require a deviation. The following documents the specific deviations. Changes have been submitted to RV-C standard committee for consideration, and this guide will be updated pending the resolution of those submissions.

Addition to the RV-C specification: Charger Status 2.
Scheduled for inclusion in next revision using PGN #1FEA3h.

// Charger Status2 - 1FEA3h 
// Input:  
//  - Instance              Instance of charger  
//  - DC Source Instance    DC Instance (bus) ID associated with  
//  - Device Priority       Relative ranking of DC charging Source  
//  - DC Voltage            0..3212.5v, in 50mV steps  
//  - DC Current            -1600..1612.5a, in 50mA steps (0x7D00 = 0A)  
//  - Temperature           -40..210 in deg-C, in 1C steps

Charger Type designation has been added to all the 'Charger' DGNs via the upper nibble of the existing Instance byte. (6.21.x in December 2015 release of RV-C spec). This allows for a common approach to all charging sources, while being able to segregate the different type of chargers. With this, device specific DC charging messages not be used.

Global usage of Generator Instance. RV-C specification assumes only one generator per vehicle. Many applications support more than one generator. An extension is to use the Generator Instance bits 0..3 as per the following:

| Byte | Bit    | Name     | Data Type | Unit | Value Description                    |
|------|--------|----------|-----------|------|--------------------------------------|
| 0    | 0 to 4 | Instance | bit4      | -    | 0000- not used  <b>  1110 - not used |
|      | 5 to 7 | RESERVED | bit4      | -    | 0000b                                |

Note that the Generator Instance nibble will be the same as the Charger instance nibble

Please note, this lib is under development. Several functions have not been tested - so expect bugs to be found and corrected.