Get any supported Linux distro. And install EVA ICS with the default settings:
curl geteva.cc | sh /dev/stdin -a
The above command prepares the system, installs all EVA ICS components on a single machine to “/opt/eva” directory and automatically links them together. “eva” and “eva-shell” commands are automatically added into the system path with symlinks in “/usr/local/bin”.
Alternatively, EVA ICS docker image can be used.
Let us have a temperature sensor and a fan, both connected with Modbus to the local serial port. We want to:
- Monitor state of both and control the fan from UI
- Turn the fan on when the temperature reaches 25C.
- Turn the fan off when the temperature reaches 22C.
Connecting the equipment
Equipment in EVA ICS is managed by Universal Controller.
It is much faster to use the interactive mode (“eva -I” or “eva-shell”), which has auto-completion for everything and other cool features, but in this document commands are provided as they should be executed from the system shell.
Why command-line? Where is a web interface? Well, EVA ICS has the web interface: Cloud Manager. But setting up from command-line is much quicker and can be also automated with scripts, can’t it? Furthermore, setting up production systems manually is absolutely not recommended, as EVA ICS has the very powerful and modern IaC and deployment.
Download Modbus PHI modules. PHI = PHysical Interface modules, which are used by UC to form drivers. When PHI module is loaded, the “default” driver is created automatically, providing the most typical logic for the supported equipment.
eva uc phi download https://get.eva-ics.com/phi/modbus/modbus_xvunit.py eva uc phi download https://get.eva-ics.com/phi/modbus/modbus_sensor.py
Define Modbus virtual port. Consider the bus is on /dev/ttyS0 (system RS-232 port #1):
eva uc modbus create local0 rtu:/dev/ttyS0:8600:8:N:1 --lock
EVA ICS modules use virtual ports for field buses. This allows different modules (e.g. drivers) to share the same port, locking it for commands if required. For Modbus over TCP or UDP locking is obviously not necessary.
If Docker image is used, either map ttyS0 device from the host or run the container in privileged mode. If local port is used, either install/run EVA ICS under root, or make sure the user has read-write access to the device.
Create the items. There are two types of equipment items in UC: units (can be controlled) and sensors (can be monitored only).
eva uc create unit:room1/fan --enable eva uc create sensor:room1/temp --enable
Define drivers and assign them to the items. Consider the fan control relay is on Modbus unit 0x01 and is controlled by coil #0 and the temperature sensor is on Modbus unit 0x02 and its value is stored in holding registers h0-h1 as IEEE 754a 32-bit float.
eva uc phi load mctrl modbus_xvunit -c port=local0,unit=1 eva uc phi load mmon modbus_sensor -c port=local0,unit=2 # for modbus drivers "port" means a register eva uc driver assign unit:room1/fan mctrl.default -c port=c0 eva uc driver assign sensor:room1/temp mmon.default -c port=h0,_type=f32 # let us query the sensor value every 5 seconds eva uc config set sensor:room1/temp update_interval 5 # check the sensor value eva uc state -p sensor # turn on / off the fan manually, "-w 5" means wait 5 seconds for the # action finish eva uc action toggle unit:room1/fan -w 5 # check the fan (visually and the unit status) eva uc state -p unit
Logic in EVA ICS is managed by Logic Manager.
eva lm rule create if sensor:room1/temp.value \> 25 then @action\(unit:room1/fan, status=1\) -E eva lm rule create if sensor:room1/temp.value \< 22 then @action\(unit:room1/fan, status=0\) -E
As the rules are created from the system shell, do not forget to screen special symbols with slashes. “@” symbol tells the rule to call macro function “action” directly, instead of compiling and executing a user-defined macro.
Check that LM PLC has all states from UC:
eva lm remote
If the items are already loaded from UC, their states are synchronized in real-time on a single machine, the same is when controllers are on different cloud nodes. Real-time always and everywhere, this is the way EVA ICS works.
The newly created UC items are loaded to LM PLC automatically every 30 seconds by default. To load them manually, use “eva lm controller reload” command.
The logic is ready. LM PLC will monitor the temperature and switch the fan automatically.
Building a very simple Human-Machine Interface
Interfaces and combined API for 3rd-party applications in EVA ICS are provided by SCADA Final Aggregator.
Check that SFA has all states from UC:
eva sfa remote
The newly crated UC and LM PLC items are synced with SFA automatically every 30 seconds. To sync them manually, use “eva sfa controller reload” command.
Install EVA JS Framework:
eva sfa server pkg-install -w 60 https://github.com/alttch/eva-js-framework/releases/download/v0.3.24/eva-js-framework-0.3.24.evapkg
By default, EVA ICS creates in SFA “operator” API key and “operator” user, but let us create a new API key and use it directly:
eva sfa key create op eva sfa key set op key 123 eva sfa key set op groups '#'
Note that after calling fan actions, UI app does not need to update the button value. The value is updated in real-time by “$eva.watch” as soon as the server reports that the action is completed.
Go to http://localhost:8828 (or IP of your system) and HMI application is ready to go:
That is all. After understanding this simple example, read other sections of EVA ICS documentation to discover the real power of this mighty open-source Industry-4.0 automation platform. Good luck!