Realtime DB access and indication

[Roland]

Hello,

We are encountered some issues regarding to realtime data acquisition and display using KpMqtt. Our plan is to receive data through an MQTT broker from many sensors at the same time, using postgresql database. Once a new data is received, the ModDBExport.log file receives a new entry:

Unable to enqueue current data. The maximum size of the queue 100 is exceeded

Can you help me how to proceed with this?

My next question is that is it possible somehow to show realtime data on a chart contionously, without refreshing the webpage? Like shifting a window on the actual data from the previous 1 minute? Or it is possible to have such only in 1 minute intervals?

In general, is there a simply solution how to handle realtime data?

We are trying to build up a system based on Rapid SCADA to design a mass ventilator system for treatment of group illnesses, specifically to COVID19.

[Mikhail]

Hello Roland,

Unable to enqueue current data. The maximum size of the queue 100 is exceeded

2 main possible reasons:
1. Query is too slow comparing with the amount of incoming data
2. There is a database error.

You should analyze the log ModDBExport.log written by the DB export module. You could provide the log here.

[Mikhail]

show realtime data on a chart contionously, without refreshing the webpage?

We work on it now. Coming soon ))
You can contact us by email to get early version for testing.

We are trying to build up a system based on Rapid SCADA to design a mass ventilator system for treatment of group illnesses, specifically to COVID19.

Wow

[Mikhail]

To get quick results with export data to PostgreSQL, it would be useful to involve our team in the project. We can help to fix the export process, and upgrade the export module if necessary depending on the requirements.

[Roland]

Thank for the answers. Please find here the corresponding lines from the ModDBExport.log :

——————————————————————————–
2020-04-02 17:45:13 Start ModDBExport module
2020-04-02 17:45:13 Error initializing data source PostgreSQL – localhost: Could not load type of field ‘Npgsql.NpgsqlConnection:CertificateSelectionCallback’ (9) due to: Could not resolve type with token 01000058 from typeref (expected class ‘Mono.Security.Protocol.Tls.CertificateSelectionCallback’ in assembly ‘Mono.Security, Version=4.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756’) assembly:Mono.Security, Version=4.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756 type:Mono.Security.Protocol.Tls.CertificateSelectionCallback member:(null)

[greenfoxx]

Could you provide versions ScadaServer, ModDBExport and PostgresSQL?

[Roland]

I am using the scada_5.8.0_mono_en package, that I downloaded from here: https://rapidscada.org/download-all-files/download-rapid-scada/

I am using Ubuntu 19.10

[Mikhail]

Try the following:
1. Download Mono.Security.dll.zip.
2. Put the DLL into /opt/scada/ScadaServer/Mod
3. Restart the Server daemon

[Roland]

I downloaded and copied there, then restarted my PC.

Now I got the following in ModDBExport.log:

Error connecting to DB PostgreSQL – localhost: Could not load type of field ‘System.Net.Security.SslStream:provider’ (0) due to: Could not resolve type with token 01000030 from typeref (expected class ‘Mono.Security.Interface.MonoTlsProvider’ in assembly ‘Mono.Security, Version=4.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756’) assembly:Mono.Security, Version=4.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756 type:Mono.Security.Interface.MonoTlsProvider member:(null)

[Mikhail]

Then vice versa, delete /opt/scada/ScadaServer/Mod/Mono.Security.dll and restart the Server daemon.

[Author]

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