opc_app

This is a simple API that exposes a few routes to request information from the KEP

This app will make the following routes available at:

http://:5000

Depending on the router configuration you will be able to access this gateway from outside the local network as well, i.e. if it is NAT'd out.

Routes

GET / OR /api

Test if the API is alive

{
  "message": "opc http endpoint is alive"
}

GET /api/sensor/\

Fetch the list of available servers to connect to

{
  "quality": "Good",
  "time": "02/01/19 07:08:28",
  "value": 10614
}

GET /api/servers

Fetch the list of available servers to connect to

{
  "servers": ["Kepware.KEPServerEX.V6"]
}

GET /api/nodes/\

Fetch the list of nodes

{
  "nodes": [
    "_AdvancedTags",
    "_ConnectionSharing",
    "_CustomAlarms",
    "_DataLogger",
    "_EFMExporter",
    "_IDF_for_Splunk",
    "_IoT_Gateway",
    "_LocalHistorian",
    "_Redundancy",
    "_Scheduler",
    "_SecurityPolicies",
    "_SNMP Agent",
    "_System",
    "Channel1",
    "Data Type Examples",
    "Simulation Examples",
    "XMPro"
  ]
}

Pre-requisites

Make sure everything installed is 32-bit (even on a 64-bit os)

Git BASH

Install git BASH. We will use this terminal emulator to run our program that will communicate with the PLC server.

There is no need to change any of the default settings during the installation process except the below caveats.

When installing git BASH the installer will ask you how you would like to use it from the command line. Select the option the same as the image below.

The installer will also ask you which terminal emulator you would like to use, we will use Winows' default console.

Python 2.7

Install Python 2.7 32-bit (if it is not already).

Ensure that python gets added to Path. Make sure the small symbol next to Add python..exe to Path does not have a cross through.

Check the installation is working by opening git BASH and executing the following.

python

Expected output.

Pywin32

Install the 32-bit version of pywin32 for python 2.7.

OpenOPC

Install the OpenOPC library.

During the installation you'll be asked to choose the components you want to install. Uncheck the OPC Gateway service.

Quick Start

After all pre-requisites the following steps should get the API up and running

Install the app

Open git BASH and run the following command to install the app.

pip install opc-app

Run it!

xmpro-demo-app

On the first time you run this program you may be prompted by Windows about allowing python to communicate through the firewall. We want to allow incoming connections so we need to make sure both boxes are checked like in the image below.

Test it!

Open the browser and browse to any of the routes. Try browsing to http://localhost:5000/api and you should see the following.

If you are using edge you will need to make sure you type the http:// in front of the web adress or it will probably not work.

Close it!

You will need to close git BASH by clicking the red cross. Ctrl-c does not appear to be working at this point.