https://github.com/patrickjmcd/node-ethernet-ip-scanlist
Ethernet/IP Scan List
https://github.com/patrickjmcd/node-ethernet-ip-scanlist
plc rockwell
Last synced: 7 months ago
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Ethernet/IP Scan List
- Host: GitHub
- URL: https://github.com/patrickjmcd/node-ethernet-ip-scanlist
- Owner: patrickjmcd
- License: mit
- Created: 2018-04-24T20:20:12.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2018-05-02T19:28:39.000Z (over 7 years ago)
- Last Synced: 2024-12-28T09:27:50.801Z (9 months ago)
- Topics: plc, rockwell
- Language: JavaScript
- Size: 45.9 KB
- Stars: 3
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Node Ethernet/IP Scan List
[](https://www.npmjs.com/package/ethernet-ip-scanlist)
[](https://github.com/patrickjmcd/node-ethernet-ip-scanlist/blob/master/LICENSE)
[](https://github.com/patrickjmcd/node-ethernet-ip-scanlist)
A small plugin to help with scanning a list of tags.
## Installation
```Shell
npm install --save ethernet-ip-scanlist
```
or
```Shell
yarn add ethernet-ip-scanlist
```
## API
### ScanTag
The ScanTag class wraps the ethernet-ip tag with the ability to react periodically or to value changes.
#### ScanTag Constructor
The ScanTag class is constructed with the following parameters:
- tagName: the tag name in the PLC
- vanityName: Description or cleaned-up name (often used for gauges or graphing)
- storePeriod: max number of minutes between periodic value updates. This can be disabled by setting the parameter = 0
- storeChangeDelta: max absolute value change before the value is updated. This can be disabled by setting the parameter = 0
#### ```ScanTag.gotValue(value, force=false)```
Function to be called when a new value is read by the PLC.
Returns an object ```{ storeValue: , reason: }```
### ScanList
The ScanList class holds the configuration and values of all the tags added to the list.
#### ScanList Constructor
The ScanList class is constructed with the following parameters:
- ipAddress: the IP address of the PLC (it is also possible to pass a FQDN to this parameter)
- slot (optional, default = 0)
- scanRate (optional, default = 200ms): the rate at which the PLC is scanned
#### ```add(tagName, vanityName, storePeriod, storeChangeDelta)```
Creates a ```ScanTag``` with the given parameters.
#### ```remove(tagName)```
Removes a ```ScanTag``` from the ```ScanList``` with the given tag name.
## Events
Since the ```ScanList``` class extends ```EventEmitter```, it has the ability to emit events, two of which have been defined:
### 1. ```Updated```
The ```Updated``` event is emitted by the ```ScanList``` class when a tag's value has changed or the tag has been updated by the ```keepAlive``` parameter of the tag. This could be a minor change or no change at all. This event is useful for displaying values on an HMI screen or updating an in-memory value.
The event is emitted with a payload of the updated ```ScanTag```.
### 2. ```newValue```
The ```newValue``` event is emitted by the ```ScanList``` class when any of the following are true:
- The tag's value has changed by more than the ```storeChangeDelta```
- The amount of time specified in the ```storePeriod``` has elapsed
- The ```force``` parameter was ```true``` when calling ```gotValue```
- There was no previous stored value or timestamp for the tag.
This event is useful for pushing values to a remote monitoring system or storing to a database.
The event is emitted with a payload of the updated ```ScanTag```.
## Usage
```Javascript
const { ScanList } = require("ethernet-ip-scanlist");
const scanList = new ScanList("192.168.1.1", 0);
scanList.add("analog_1_value", "Pressure Reading", 1, 60.0);
scanList.add("digital_2_status", "Valve Status (NC)", 1, 0);
scanList.start();
scanList.on("newValue", (tag) => {
console.log(tag.vanityName, tag.value, tag.lastSendReason);
});