Configurable ComputerCraft SCADA system for multi-reactor control of Mekanism fission reactors with a GUI, automatic safety features, waste processing control, and more!
> Supervisory control and data acquisition (SCADA) is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also covers sensors and other devices, such as programmable logic controllers, which interface with process plant or machinery.
This project implements concepts of a SCADA system in ComputerCraft (because why not? ..okay don't answer that). I recommend reviewing that linked wikipedia page on SCADA if you *want* to understand the concepts used here.
There can only be one of these. This server acts as a hybrid of levels 3 & 4 in the SCADA diagram above. In addition to viewing status and controlling processes with advanced monitors, it can host access for one or more Pocket computers.
There should be one of these per facility system. Currently, that means only one. In the future, multiple supervisors would provide the capability of coordinating between multiple facilities (like a fission facility, fusion facility, etc).
RTUs are effectively basic connections between a device and the SCADA system with no internal logic providing the system with I/O capabilities. A single Advanced Computer can represent multiple RTUs as instead I am modeling an RTU as the wired modems connected to that computer rather than the computer itself. Each RTU is referenced separately with an identifier in the modbus communications (see Communications section), so a single computer can distribute instructions to multiple devices. This should save on having a pile of computers everywhere (but if you want to have that, no one's stopping you).
The RTU control code is relatively unique, as instead of having instructions be decoded simply, due to using modbus, I implemented a generalized RTU interface. To fulfill this, each type of I/O operation is linked to a function rather than implementing the logic itself. For example, to connect an input register to a turbine `getFlowRate()` call, the function reference itself is passed to the `connect_input_reg()` function. A call to `read_input_reg()` on that register address will call the `turbine.getFlowRate()` function and return the result.
PLCs are advanced devices that allow for both reporting and control to/from the SCADA system in addition to programed behaviors independent of the SCADA system. Currently there is only one type of PLC, and that is the reactor PLC. This is responsible for reporting on and controlling the reactor as a part of the SCADA system, and independently regulating the safety of the reactor. It checks the status for multiple hazard scenarios and shuts down the reactor if any condition is met.
There can and should only be one of these per reactor. A single Advanced Computer will act as the PLC, with either a direct connection (physical contact) or a wired modem connection to the reactor logic port.
## Communications
A vaguely-modbus [modbus](https://en.wikipedia.org/wiki/Modbus) communication protocol is used for communication with RTUs. Useful terminology for you to know:
- Discrete Inputs: Single Bit Read-Only (digital inputs)
HMAC message authentication is available as a configuration option to prevent replay attacks and generally prevent control or false data reporting within a system's network. This is done utilizing the [lua-lockbox](https://github.com/somesocks/lua-lockbox) project.
