I was testing OH1.x and now OH2, just to see how fast it runs and some fundamental features. I’m glad, the test results were good and I think OH2 could be used for another kind of application as a SCADA System. So, my question is:
How far do you think is OH2 to be a SCADA system?
for example, to implement:
Dynamic mimic, with the image of the process and variable inside it. http://www.progea.com/
Alarms, a module to manage the alarms
I think OH could be a good start point product to be implemented as a Process SCADA, as well.
I believe it depends on your application. openHAB is not meant to be a generic process modelling or visualization system and while its programming capabilities are fine for home use, it doesn’t have many APIs into industrial type of applications and it’s dynamic visualizations capabilities aren’t as great, and it’s not real-time proof.
I wouldn’t use it to run a nuclear power plant (that’s the context where I heard the term ‘SCADA’ first).
Yes, for home application it is a nice solution, I think there are a lot of application it can be used too. For example, if you want to monitor and control no critical system like Brewing Process Control, where you monitor a multitude of variables – temperature, humidity, pH, pressure etc. Those variable are not critical and, in all cases, the process control algorithm must be implemented on a PLC or another kind of Controller. From the SCADA system you only change the setpoint of variables, show the state (not hard real time), show trending chart, manage alarms, configure your system, etc.
Yes, but modbus, for example, is a standard open protocol very common in the industry, but like you say, it’s needed some others binding like profibus, BACnet, DNP3, etc.
This is, from my point of view, the biggest challenge of openHAB as SCADA system.
The “hard” real time control system, normally, must be implemented in the controller device like PLCs, RTU, etc. So you don’t need to care about that, the SCADA system is a human interface and our eyes have a low sample period. All data and control rules will be implemented in dedicated devices. So, If devices send the couple Variable_Value:Time_Stamp it is possible to get the trending chart in any moment.
Neither me, just some very few specific SCADAs in the world have the restriction and certification needed to be used in the nuclear plant. And for sure, this is the smaller market in this field and just the big big companies have access to it.
OH is not real-time and based on that basic alone I would be hesitant to deploy OH for SCADA or Industrial Control. That being said, based on your further elaborations that may not matter.
Another thing OH is lacking, which I’ve been thinking about in my own mind on how to do, is good support for state machines. So defining complex flows and monitoring and reacting to states will become a little difficult to define and implement inside OH.
But also based on your elaborations it sounds a lot less like you are controlling anything and more like you are just monitoring in which case what you are really doing is using OH as a big database charting and viewer. So why not skip the middleman and just dump the data into a DB and use a good charting and visualization tool?
At this time OH is not capable of producing a visualization anything close to the one you linked to, though through MQTT and the REST API it can surely drive such a visualization.
Ultimately, I question OH’s suitability in this sort of deployment though I’m positive it could be made to work if one were really bound and determined to try.
I completely agree! It’s a little “unfair” to use a Nuclear power plant as a comparison since this type of process is definitely at the very extreme end of the scale in terms of need for integrity, safety, reliability, etc.
The bulk of SCADA systems deployed worldwide are serving processes that are far less critical. As a matter of fact I am working on such a system for an offshore wind farm at the moment,
A SCADA system is mostly about visualization (i.e. essentially an HMI) and this is IMO really not covered by openHAB (apart from very basic support for sitemaps and dashboards).
