Modbus Data FROM Webpage HTML

[careythibodeau]

Hey all,
I am trying to find a way to get data from a local device webpage into a modbus server for a customers SCADA.


The customer was hoping that instead of spending money on service techs to program CAN modules etc, that we could somehow get the data off these compressors without needing all the vendor's proprietary junk.



Is there any way I could pull a few tags off an HTML webpage and have them update modbus data points? Is there anyway to directly import these tags into a Studio 5000 program?


Yes, its an obscure and weird situation, i am well aware hahah

 

[glennz]

Never did it, but I understood this was the sort of task Node-Red was capable of. Someone will respond shortly, I'm sure...

We asked this question of Rockwell at one time when we needed a reservoir water elevation from a USACE website. Their response was "you could use the EtherNet/IP Socket Interface". Never pursued it, but there might be something you could do. Look at their Publication ENET-AT002E-EN-P.

 

[Ken Roach]

>data off these compressors

What sort of compressors are you using, with what kind of Ethernet interface ?

Do you know if they implement a simple HTML sort of webpage, or if they have a more complex java applet or HTML5 visualization system ?

I would start by opening their webpage in a browser, right-clicking and selecting "View Page Source" (in Chrome, anyhow) and looking for the data you want in the source HTML file.

I agree that's something I would reach for Node-Red and a small Linux box to accomplish.

I presume your SCADA system's most generic interface is Modbus/TCP, but you also have some ControlLogix or CompactLogix in the system.

 

[drbitboy]

I would start by opening their webpage in a browser, right-clicking and selecting "View Page Source" (in Chrome, anyhow) and looking for the data you want in the source HTML file.

+1

I did some searching, and stumbled onto this: https://palewi.re/docs/first-web-scraper/

Update: the code is available on Github, and the example, to extract data from a table here, looks like this:

import csv

import requests

from bs4 import BeautifulSoup



url = 'https://report.boonecountymo.org/mrcjava/servlet/SH01_MP.I00290s?max_rows=500'

response = requests.get(url, headers={'User-Agent': 'Mozilla/5.0'})

html = response.content



soup = BeautifulSoup(html)

table = soup.find('tbody', attrs={'class': 'stripe'})



list_of_rows = []

for row in table.findAll('tr'):

    list_of_cells = []

    for cell in row.findAll('td')[:-1]:

        text = cell.text

        list_of_cells.append(text)

    list_of_rows.append(list_of_cells)



outfile = open("inmates.csv", "w")

writer = csv.writer(outfile)

writer.writerow(["Last", "First", "Middle", "Suffix", "Gender", "Race", "Age", "City", "State"])

writer.writerows(list_of_rows)

​