Controller API

The Basics

Getting Connected

const { Controller } = require("ethernet-ip-cip");

const PLC = new Controller();

// Controller.connect(IP_ADDR[, SLOT])
// NOTE: SLOT = 0 (default) - 0 if CompactLogix
PLC.connect("192.168.1.1", 0).then(() => {
    console.log(PLC.properties);
});

Controller.properties Object

 {
    name: String, // eg "1756-L83E/B"
    serial_number: Number, 
    slot: Number,
    time: Date, // last read controller WallClock datetime
    path: Buffer,
    version: String, // eg "30.11"
    status: Number,
    faulted: Boolean,  // will be true if any of the below are true
    minorRecoverableFault: Boolean,
    minorUnrecoverableFault: Boolean,
    majorRecoverableFault: Boolean,
    majorUnrecoverableFault: Boolean,
    io_faulted: Boolean
}

Set the Clock of the Controller

NOTE Controller.prototype.readWallClock and Controller.prototype.writeWallClock are experimental features and may not be available on all controllers. 1756-L8 ControlLogix Controllers are currently the only PLCs supporting these features.

Sync Controller WallClock to PC Datetime

const { Controller } = require("ethernet-ip-cip");

const PLC = new Controller();

PLC.connect("192.168.1.1", 0).then(async () => {
    // Accepts a JS Date Type
    // Controller.writeWallClock([Date])
    await PLC.writeWallClock(); // Defaults to 'new Date()'
});

Set Controller WallClock to a Specific Date

const { Controller } = require("ethernet-ip-cip");

const PLC = new Controller();

PLC.connect("192.168.1.1", 0).then(async () => {
    const partyLikeIts1999 = new Date('December 17, 1999 03:24:00');
    await PLC.writeWallClock(partyLikeIts1999); // Pass a custom Datetime
});

Reading Tags

NOTE: Currently, the Tag Class only supports Atomic datatypes (SINT, INT, DINT, REAL, BOOL). Not to worry, support for STRING, ARRAY, and UDTs are in the plans and coming soon! =]

Reading Tags Individually...

const { Controller, Tag } = require("ethernet-ip-cip");

const PLC = new Controller();

// Create Tag Instances
const fooTag = new Tag("contTag"); // Controller Scope Tag
const barTag = new Tag("progTag", "prog"); // Program Scope Tag in PLC Program "prog"

PLC.connect("192.168.1.1", 0).then(async () => {
    await PLC.readTag(fooTag);
    await PLC.readTag(barTag);

    console.log(fooTag.value);
    console.log(barTag.value);
});

Additional Tag Name Examples ...

const fooTag = new Tag("Program:prog.progTag"); // Alternative Syntax for Program Scope Tag in PLC Program "prog"
const barTag = new Tag("arrayTag[0]"); // Array Element
const bazTag = new Tag("arrayTag[0,1,2]"); // Multi Dim Array Element
const quxTag = new Tag("integerTag.0"); // SINT, INT, or DINT Bit
const quuxTag = new Tag("udtTag.Member1"); // UDT Tag Atomic Member
const quuzTag = new Tag("boolArray[0]", null, BIT_STRING); // bool array tag MUST have the data type "BIT_STRING" passed in

Reading Tags as a Group...

const { Controller, Tag, TagGroup } = require("ethernet-ip-cip");

const PLC = new Controller();
const group = new TagGroup();

// Add some tags to group
group.add(new Tag("contTag")); // Controller Scope Tag
group.add(new Tag("progTag", "prog")); // Program Scope Tag in PLC Program "prog"

PLC.connect("192.168.1.1", 0).then(async () => {
    await PLC.readTagGroup(group);

    // log the values to the console
    group.forEach(tag => {
        console.log(tag.value);
    });
});

Writing Tags

NOTE: You MUST read the tags first or manually provide a valid CIP datatype. The following examples are taking the latter approach.

Writing Tags Individually...

const { Controller, Tag, EthernetIP } = require("ethernet-ip-cip");
const { DINT, BOOL } = EthernetIP.CIP.DataTypes.Types;

const PLC = new Controller();

// Create Tag Instances
const fooTag = new Tag("contTag", null, DINT); // Controller Scope Tag
const barTag = new Tag("progTag", "prog", BOOL); // Program Scope Tag in PLC Program "prog"

PLC.connect("192.168.1.1", 0).then(async () => {

    // First way to write a new value
    fooTag.value = 75;
    await PLC.writeTag(fooTag);

    // Second way to write a new value
    await PLC.writeTag(barTag, true);

    console.log(fooTag.value);
    console.log(barTag.value);
});

Writing Tags as a Group...

const { Controller, Tag, TagGroup, EthernetIP } = require("ethernet-ip-cip");
const { DINT, BOOL } = EthernetIP.CIP.DataTypes.Types;

const PLC = new Controller();
const group = new TagGroup();

// Create Tag Instances
group.add(new Tag("contTag", null, DINT)); // Controller Scope Tag
group.add(new Tag("progTag", "prog", BOOL)); // Program Scope Tag in PLC Program "prog"

PLC.connect("192.168.1.1", 0).then(async () => {
    // Set new values
    fooTag.value = 75;
    barTag.value = true;

    // Will only write tags whose Tag.controller_tag !== Tag.value
    await PLC.writeTagGroup(group);

    group.forEach(tag => {
        console.log(tag.value);
    });
});

Lets Get Fancy

Subscribing to Controller Tags

const { Controller, Tag } = require("ethernet-ip-cip");

const PLC = new Controller();

// Add some tags to group
PLC.subscribe(new Tag("contTag")); // Controller Scope Tag
PLC.subscribe(new Tag("progTag", "prog")); // Program Scope Tag in PLC Program "prog"

PLC.connect("192.168.1.1", 0).then(() => {
    // Set Scan Rate of Subscription Group to 50 ms (defaults to 200 ms)
    PLC.scan_rate = 50;

    // Begin Scanning
    PLC.scan();
});

// Catch the Tag "Changed" and "Initialized" Events
PLC.forEach(tag => {
    // Called on the First Successful Read from the Controller
    tag.on("Initialized", tag => {
        console.log("Initialized", tag.value);
    });

    // Called if Tag.controller_value changes
    tag.on("Changed", (tag, oldValue) => {
        console.log("Changed:", tag.value);
    });
});

Demos

• Monitor Tags for Changes Demo

const { Controller, Tag } = require("ethernet-ip-cip");

// Intantiate Controller
const PLC = new Controller();

// Subscribe to Tags
PLC.subscribe(new Tag("TEST_TAG"););
PLC.subscribe(new Tag("TEST", "Prog"););
PLC.subscribe(new Tag("TEST_REAL", "Prog"););
PLC.subscribe(new Tag("TEST_BOOL", "Prog"););

// Connect to PLC at IP, SLOT
PLC.connect("10.1.60.205", 5).then(() => {
    const { name } = PLC.properties;

    // Log Connected to Console
    console.log(`\n\nConnected to PLC ${name}...\n`);

    // Begin Scanning Subscription Group
    PLC.scan();
});

// Initialize Event Handlers
PLC.forEach(tag => {
    tag.on("Changed", (tag, lastValue) => {
        console.log(`${tag.name} changed from ${lastValue} -> ${tag.value}`);
    });
})