SDK for Embedded Systems

General topics regarding OPC Foundation and communication technology in general.

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JoseAdeilmo
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SDK for Embedded Systems

Post by JoseAdeilmo »

Hello,

I saw that Unified Automation make it work the OPC UA with the 14 specification using MQTT (https://www.unified-automation.com/news ... asier.html), i'm working with a plataform with the following specifications: 512 Kb of Flash memory, 96 Kbytes of SRAM, frequency up to 84 MHz and Data Bus of 32 bits.

I want know if the Unified Automation will provide some sdk for this purpose.

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Support Team
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Re: SDK for Embedded Systems

Post by Support Team »

Hello Jose,

at the moment we are working on a PubSub addon for our OPC UA SDKs.
Publishers/Subscribers normally can be configured via OPC UA Client/Server protocol
and the information model provided by OPC UA.
For such small devices, this will get difficult.
But it is possible to create a pure UA Publisher with static configuration and without a UA Server and its information model.
So yes, this is possible.
However, this has limitations. You cannot change any configuration via a standard mechanism, nor can your use security (encryption/signing).

Regarding MQTT transport. We have implemented the UADP transport protocol for PubSub, not MQTT.
MQTT is such a simple transport protocol that you can do this on your own or use an existing library to integrate it into our SDKs.
MQTT is just a transport protocol and does not describe its data, or defines any format of the payload.
In the IOT world, many people use JSON data, which is pretty much self-explanatory, but inefficient compared to binary.
In OPC UA Pub/Sub we can send UA binary over MQTT, and the meta data of datatypes is provided via the OPC UA Server.

You see, OPC UA Client/Server is still very important, even when using Pub/Sub.
With a little bit more RAM you can implement a full UA Server on an embedded device.
See https://forum.unified-automation.com/do ... ochure.pdf for more information.
Best regards
Unified Automation Support Team

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