HMI Design – Backend

This figure show a key principle in modern HMI design. I have only illustrated 2 input signals, but the principle is the same regardless of what signal or what hardware you use.

Using a analogue signal as an example you collect that from a sensor or ADC channel. The signal will then be normalized and scaled, before it is processed. This is ether done in your device or in a backend server. Maybe you have a modbus serial RTU protocol transferring from a remote device to your backend, but the backend server will only present the finished, normalised signal that is processed according to your specification.

The Front-end part is actually simpler because you only receive the signal and connect it to a gauge that does the precentation. At this stage you don’t care wherever the gauge is an analogue meter, bar or just a number on the screen – backend precent a normalized signal, front end do the visual precentation.

Obviously front-end also need to configure the entire chain and configuration will be device specific.

The backend in my system have a name – it is called easyIPC and consist of several protocols,  servers and external protocol interfaces. Having a healthy backend design makes building the frontend so much easier.

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