IOT Platform
Internal Technical Documentation for Node.IOT Platform.
The Node.IOT platform was designed to make smart IOT based devices easy and inexpensive. The killer feature is a Web-based real-time Ladder Logic processor to allow the creation of custom control logic. The ladder editor runs in the browser and once the program is saved to the Node it runs independently. No other device is required, it is completely standalone.
The Node.IOT platform is divided into two logical systems: The core operating system Node.IOT.OS and the Web Interface and Node.IOT.Web.
The Node.IOT.OS operating system handles the real time network and hardware interface and service the web requests, AJAX, websockets, REST and TCP based IO. It also hosts the Logic engine which is used to run the ladder logic program. The ladder logic can be emulated in the browser to make coding and debugging easier. A extensive library of examples and demo projects will be provided
A minimum web server runs on the OS to serve the static HTML and process AJAX/WebSockets requests. The static HTML and config files are stored in on-board flash and accessed through the XXX filesystem. The javascript portion of the web interface runs on the client browser.
The ESP32 core is arduino compatible so that the project can be compiled with the normal Arduino IDE and work with Arduino libraries.
Todo: Add install instructions Need to set sketchbook location
The logic processor processor emulates a simple bytecode based CPU.The CPU state is loaded from bytecode.txt during startup.
The CPU has a single register called CR, or 'current result'. The register contains the current evaluation state of rung processing. It gets reset to with a '' command. Operations that results in a 1 state will not affect it. An operation resulting in a 0 will clear it.
The CR stack maintains previous CR results to allow branch evaluation
The OR stack maintains the results of previous branches so that the COLLECT instruction can evaluate previous results.
Memory is divided into partitions using a variable partition table. The following types of memory are supported:
| Type | Data |
|---|---|
| Bit | 1Bit Value |
| Byte | 8 Bit Value |
| Word | 16 Bit Value |
| Int | 32 Bit Value |
| Float | 32 Bit Floating Point |
| Timer | 16 bit Timer |
| Counter | 16 bit Counter |
Composite memory types have mode have multiple values.
| Name | Type |
|---|---|
| Value | Current state |
| TB | Timebase. 0 =1ms, 1 = 0.01 sec, 2 = 0.1 sec, 3: 1 sec. |
| PRE | 16 bit preset |
| ACC | 16 bit accumulator |
| Name | Type |
|---|---|
| Value | Current state |
| PRE | 16bit preset |
| ACC | 16 bit accumulator |
| Name | Type |
|---|---|
| H | 8 Bit Hour |
| M | 8 Bit Minute |
| S | 8 Bit Second |
| Name | Use |
|---|---|
| XIO | Examine if Open |
| XIC | Examine if Closed |
| OTE | Output Energize |
| OTL | Output Latch |
| OTU | Output Unlatch |
| TMR | Timer |
| TIME | Time window compare. |
Accumulates if source high
True if current time is greater or equal to the low lim and less that the low limit. Supports 24h wrap around
These are generated by the compiler for housekeeping
| Name | Use |
|---|---|
| PUSHCR | Push cr to cr stack |
| POPCR | Pop cr from cr stack |
| PUSHOR | Push cr to or stack |
| POPOR | Pop value from or stack and or CR with it |
The web interface files are stored in the /data directory of the arduino project to allow the firmware tool to copy them to the device
The web interface is divider into modules accessed from the navigation bar on the left side.
Overall project control. Allows load, save, assemble
Interactive display for displaying current values
Display all current inputs and outputs
Live ladder logic editor
Select mode allows the users to modify the options of a cell instruction
Toggle mode toggles the source bit of an instruction
Variable configuration Project must be reassembled after adding or removing a memory element
Name local and remove IO
General configuration
System interface. Backup, Restore, restart, etc
There are a few config files stored on the device
| Name | Use |
|---|---|
| project.txt | Main JSON encoded project. Contains the node list, variables, and configs. |
| bytecode.txt | Contains the CPU bytecode and the Variable state. |
| config.txt | Contains the config file in a format that is easy for the system to read. |