Com Ports ?

[Rich Ex]

Hi All

Is it possible for RapidScada to read data from a com port connected to the PC that is running RapidScada .

I have an old device that sends a stream of ASCII characters over the com port every 5 minutes and I want capture these with my RapidScada .

The stream is like 10/10/21 10:18 21.2 23.4 5 18 20 ( it sends date time and some measurements )

I know its not a SCADA format but any thoughts please .

Thanks as always
Rich

[Mikhail]

Hi,

Rapid SCADA supports COM ports. But you also need a driver (dll) for Communicator that implements recognizing the data in a particular format. It’s possible to develop such driver.

[Rich Ex]

Hi Mikhail,
Thank you for the information .

Is there an existing example to give me an idea of where to start will a dll for the COM port .

Thanks
Richard

[Mikhail]

Hi,

Please check the driver development article and the existing driver as an example (link 1, link 2).

[Rich Ex]

Mikhail ,
Thats brilliant thank you .

I have written a stand alone program that now gets the RS232 data from the device and writes it into a text file like ‘mydata.txt’, its simple the text file just shows a single number like 22.3

Could I not just write a formula to read this ‘mydata.txt’ file into RapidScada and then return this number from the file or am I going about it the wrong way?

Maybe theres a driver to read a .txt file already ?

Thanks
Rich

[kumajaya]

If I was in your situation, since I have Mqtt broker (Mosquitto) and Node-RED installed:
Solution 1: Use python to read serial data and push it to Mqtt broker, RS as Mqtt client
Solution 2: Use Node-RED to read serial data and also set it as OPCUA server, RS as OPCUA client

[manjey73]

@rich-ex I have a driver for reading 1Wire temperature sensors on a Raspberry Pi. I didn’t manage to process 1Wire directly, so I had to write the value to txt through crontab and then process this txt from the driver. If this option is suitable, I can give you the source code of the driver.

[Mikhail]

Hi,

and writes it into a text file like ‘mydata.txt’, its simple the text file just shows a single number like 22.3

Could I not just write a formula to read this ‘mydata.txt’ file into RapidScada and then return this number from the file

This is not optimal, however, it’s possible if the file contains only 1 number.

Create a formula and use it for an input channel of the Calculated real type.

[Mikhail]

The formula would be something like:

double ReadNum()
{
  try
  {
    string s = System.IO.File.ReadAllText(@"C:\mydata.txt");
    double val;
    return double.TryParse(s, out val) ? val : -1;
  }
  catch
  {
    return -2;
  }
}

• This reply was modified 2 years, 5 months ago by Mikhail.
• This reply was modified 2 years, 5 months ago by Mikhail.

[Rich Ex]

Mikhail , manjey73 , kumajaya .

Thanks very much for you great suggestions . I will have a go and see how I get on with the different solutions … what a great forum this is ..

Kind Regards , Rich

[Rich Ex]

@manjay73

Yes if you could copy your driver and paste it here that would be very interesting .
Thanks
Rich

[manjey73]

https://cloud.mail.ru/public/rZdp/o5aELSXvM

Sensor IDs are added to the text file, and the script reads them using crontab. The driver polls the specified file and outputs a list of channels. In some places, comments in Russian may not be reflected in you.

[Rich Ex]

Mikhail ,
You said “Rapid SCADA supports COM ports. But you also need a driver (dll) ”
So would device type be ‘ACC-RS232’ , I am struggling to find any documentation on the setting up of the device types .

Sorry to be a pain but my system so far is all Scada driven which I understand , the RS232 device is turning into a pain !!

Thanks
Rich

[Mikhail]

Hi Rich,

RS-232 is just a communication interface. The most important is how data is encoded when transmitted.

Do you successfully write values to a text file?
Does the above formula to retrieve data from text file work?

[Rich Ex]

Hi Mikhail ,

Yes I can write my data to a text file no problem .
I have a compiled a .exe file to do this now .

I have not tried your formula yet , I don’t want to put it onto my live system incase I have issues as we use it our factory to monitor many devices .
I will have to build Rapid Scada on another machine to use as a “test rig” i think .
I will let you know .

Thanks
Richard

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