OpenCoral OCnet

OCnet is now available in two “flavors”, OCnet Basic and OCnet Advanced.

OCnet Basic is based upon ModBus/RTU over 2-wire RS-485.

OCnet Advanced is built around the CANbus (Controller Area Network) CAN 2.0A standard. CAN is a very well established bus, commonly used in automotive applications, for communicating amongst the various modules. It features very long bus lengths (above and beyond 100m) and high data rates.

CAN was chosen for various reasons over other established industry buses, such as Modbus.

1. Availability of dedicated hardware and software stacks for easy integration.
2. Multi-master support: allows clean reporting of exceptions and status, without requiring a single dedicated master.
3. Faster data rates than most common Modbus implementations.
4. Robust checksums, data integrity.
5. Low wire count.

MODBUS was not chosen due to its single-master nature.

OCnet Advanced devices are on a single line bus. There can be 0 or more “master controllers”, which are programmable user interface modules. There can also be 0 or more peripherals or sub-controllers, which can perform both direct and autonomous functions. For instance, a power control strip is a directed module. That is, another device needs to direct the module to change its output. On the other hand, the TipTop allows both directed and autonomous functions - it can both be controlled and also performs actions upon its own local programming.

More soon.