One of the challenges I have is the size of connectors in front of the modules. I am actually considering using Top and Bottom on the modules to increase connector space. Another issue is that the screw connectors used on the RS485 board below is not really operational from front alone. Looking at the Servo Controller I could probably add another 16 inputs of which many would be analogue.
The GSM Module above can go as is. I am however considering replacing both SIM808, W5500 and Raspberry PI. SIM808 was chosen because it has digital voice interface, but it also cost 10.- USD and occupy a lot of space. W5500 and Raspberry PI can be replaced with ESP32.
This picture show a single Gauge on a form to illustrate how HMI Designer & Browser works. In this case we have a rotating needle that needs to be associated with an input value. What we do is to save this form as an XML and include it in a device.
But, we also need to associate this needle with a variable on that device. This is no coding, only a few clicks -job done.
The next that happens is that we start HMI Browser on Windows, Linux, OSX, iOS, Android or whatever. It contact our device, upload the HMI XML and we have a working HMI with a gauge showing the value of the variable we selected.
No coding involved, just a few click & plays on the screen and job done. No more need for hours by hours from expensive C#, Java, C++, HTML5 developers- no more need for specialised HMI/GUI skills – just a few clicks & play.
And I have not even got to the best part yet…
I still have some work to do on the basic drawing/HMI engine, but will soon be focusing entirely on what I call “furniture” as in pre-made controls we can use. I will create some fancy, build in controls, but the most important one is a “User Control” enabling us to create custom controls. Now-keep in mind that the entire HMI is specified in XML format and loaded as we start the HMI Browser, so a custom control will need to be loaded as part of this. For the Designer, we would like to have a library that is made available, but only those that are used to be included in the final XML.
The User Control itself needs to be built from other controls and by adding colors, scaling, rotation etc to create a new control. This means our user control will be a list of build-in controls where we create our own, new interface. As input values can transform to position or rotation we should be able to create most controls these ways.
To enhance our customization capabilities, we have Polygon and Plain. I don’t want to dig into the same security problems as ordinary browsers, so the Plain VM will only have access to HMI Browser, not any of the host OS capabilities. If we need the later we will have other options for that.
This premature screenshot shows an early version of the HMI Designer. The designer itself is quite simple, you use the menu/commands on top to create a “diagram” and the design tools at left will come up. In this case we create a HMI, but I will re-use the framework for other diagrams later.
An HMI (or GUI screen if you like) is straight forward. You just draw the HMI components you want into the screen and assign names to them. This example only show a few rectangles and ellipses. To edit the properties you click on a symbol and change the properties using the property editor at right.
A tab field on top (not shown) will allow you to select between HMI screens as you design a project.
This concept should be well known for anyone with experience from Delphi, Visual Basic, C# etc. I want to just start with a simple HMI Designer for now. The objective is to create the HMI framework, XML format, HMI Designer and HMI Browser to an usable stage.
I will use Plain as a scripting engine capable of processing HMI events locally. In a later version I will add support for experimental diagram logic and see how that goes. I will write a separate entry about the ups- and downs- using a graphical programming language later.
HMI Browser will in reality be an app that starts up with either a file- or communication path. It can either retrieve the XML from a file or have it sent up from a device.
As for time-line an application of this nature will take some hours to get right. As it also have to be done as I teach myself Qt and are occupied in very tight projects elsewhere it will be something we need to focus on for a while. I do however have plenty of unfinished electronics that we can play with if I need a break.
One of the applications I want to create is a “HMI Designer”. This is technically very easy as I have done similar applications before. What I will do is to create a graphical application that can design square objects on a form. Each object will have a name that we can use for IO through a serial line. To make the designer a bit more WYSIWYG we animate the objects as if they where “furniture” like Text Edit, Graphic Plot, Grid, Button etc. Each object will have a list of properties that are set/get design and run-time. The result is stored as an XML file and executed by a “HMI Browser”, a special application that download the XML and interact with the system.
This way we can design config HMI’s stored in the embedded devices as XML files and we only need to re-create the HMI Browser to support HMI on Windows, Linux, OSX, Android etc. The concept is not so unlike a Web Browser with the exception that the server here can be small embedded system in a closed loop. Nextion are selling displays build on a similar concept, so in time we can do our own embedded graphics displays as well. I do however want to do tings a bit different from Nextion.
One of the differences is usage of Plain as “scripting” language and interfacing using easyIPC and RSX as well as Ethernet/Wifi. The other difference is that I want a significantly larger object library and take advantage of GPU’s on Raspberry PI etc. I also want this to be a portable software package, not locked to proprietary hardware.
The most important difference is however system thinking. I want HMI Designer & HMI Browser to be building blocks in the CASE (Computer Aided Software Engineering) Tool I want to create on top of Plain. For now we will use Plain and the HMI Designer, but I do plan a fully graphical programming concept later.
As mentioned before with my Plain blogs I want to evolve the way we do software based system development. The network I build here have plenty of fun for C programmers and electronic hobbyists, but we need to create infrastructure and tools enabling this for non-specialists.
I have been thinking a bit about creating a stand-alone HMI component. Basically a terminal with a touch display and optional keyboard, mouse and customized input equipment. The key principle would be that we use a Ethernet/RSX as bacbone for data traffic, while the HMI takes care of graphics, input etc.
This is just some random GIF I found on the net, but an HMI app could consist of a set of standard components where layout is controlled by XML files that are uploaded from the device. Communication could be Ethernet/RSX. Equiped with a Plain VM this could be an interesting concept where HMI logic is executed on the HMI unit and only events/data transferred to/from the rest of the system.
Making the app above might seem complicated, but it’s nothing I have not done before from scratch in C/C++. I am thinking more and more about creating a standard HMI app in Qt since that can run on Windows, Linux, Android, OsX etc. I need to check around for options.
Since we are talking about a network of stand-alone units we could create a full control center as well.
The latest version of the backbone bus. It is only 10cm long and with max 8 boards. Connectors are 2 x RSX, 5V PSU, and Actuator PSU’s. On the right side is jumpers and resistors for RS-485 terminator and bias.
The backbone’s can be connected in many ways simply by connecting RSX1 to RSX1 and mount the boards in any way you want. They can easily scale up from a single card to a large multiple backbone system. 32 devices can easily be directly connected, but using an active RSX switch you can scale much higher.
I think I have reached a point where I want to order PCB’s and get going. In this case I want to start with the Backbone, CCM and 3xRSX modules. I need to modify the SWD on the Servo Module + the main purpose with the Servo was actually to test the design. The Servo module have doen it’s job as it forced an important change on the backbone.
I also need to start on the 3D for the fittings and see if I can manage to print those with a 3D printer.
The RSX connectors on the backbone are high speed designed for very short range, but we can also interconnect using 3xRSX modules. I do however still need the RSX Switch with power for sensors, so I will push 2 more modules.
- The active RSX switch.
- An upgrade of my preious RSX Sensor (Temperature, humidity, light, distance).
I actually have a few RSX devices in rev 1 that need an update so we can start making a system consisting of sensors and actuators. One step at the time.
I still got a few components to make\upgrade before I have a full Home Automation network. The CCM and RSX module allows me to create a central, but I need sensors and I need to feed the sensors power. One solution to this is to create an active RSX Switch with power output on each network.
The RS-X Switch as drawn here will take 2 x Ethernet or 2 x RS-X (M1 & M2) input and provide 4 x RS-X output with power. Each of RS-X E1,E2,E3 & E4 can be switched on/off separately and be used for networks or 1:1 with sensors/actuators.
The functionality in the switch is simple message switching. The idea of having 2 x Ethernet and 2 x RS-X Input is redundancy, but I realise this might be a bit tight to achieve so will see what pins & space I have available.
This module will also be a great RS485 Hub used stand-alone.
3D of a 3-port RS485 GW. This actually have 5 RS485 (or RS-X). 2 on the backbone bus running high speed, and 3 isolated with lower speeds in front. These can be used Standard RS485, RSX or even Profibus/485.
The MCU is actually capable of running 3 port Profibus using UART’s saving the need for specialised hardware.
This module do not have the Raspberry PI Zero W add-on option. The reason is because the connector would conflict with the isolation area.
Added 2 coils on the 16 x Servo Module as well. On this I have plenty of space. I should have moved the MCU a bit down, but I will leave it for now.
This module provide output only, meaning it can not do generic IO as my previous 32xServo/IO could. The limitator is the opto couplers providing a full galvanic isolation. It can still do digital output and low frequency PWM (< 100Khz) in addition to Servo signals.
Servo PSU is selectable from 5, 12 & 24V by jumper. Signal is also selectable from 5, 12 & 24V by Jumpers. The MCU 5V is separate from the Signal/Servo 5V etc.
It is also has a 4 pin HMI – the same as on the CCM board. I simply did not see any point in removing it + might be cool for demo/testing.
Doing 16 channel Servo on a STM32F405RG is well, the reason I use a M4 is the speed of the backbone bus.