If the latter - good luck and get used to it - if the former, then lets start to get over it !
What ? I imagine you asking (rhetorically) so I answer - the following hopelessly hollow phrases..
- Let's put the 'e' back into bms.
- You can't manage what you can't measure.
- Every building is different.
- The cheapest kW is the one you never spend
- Self-Adaptive Learning Algorithm
You know why ? - because every building control system is inherently the same. And that is a huge problem for the people who make them and sell them.
Commodities they are, and the only differentiators are prices (which are falling), likelihood of going out of business (as many manufacturers do at alarming frequency), and the deliberate incompatibilities that are put in as booby-traps to snare the less knowledgeable buyer (think Internet Explorer iPhones and pretty much every closed protocol device)
So whether they are referred to as unitary controllers, nodes, programmable logic controllers, embedded supervisors, SCADA, etc etc it really doesn't matter - they are the same.
In essence they can take inputs in, process them according to some algorithm, put responses out and to be really esoteric they can communicate via "man-machine interfaces" aka screen/keyboard and via TCP/IP and a bunch of other protocols (unless you really buy a pooch). Beyond this they may have bits of network topology, data storage, protocol converters (why needed), routers and etc.
What did I just describe - well a smartphone can do all of that for under 99$ , so can arduino open source hardware and it costs peanuts in comparison with the black boxes sold by the controls industry, so can any computer. So the hardware is a sham.
What about analog sensors, (the phone has them and they cost virtually nothing), relays (oh yes every button on a keypad is a digital input).
No, in reality there is nothing to distinguish them from a hardware perspective. And remember just because a sensor can feed a 16-bit value along a comms network, if it is a thermometer it will tell you a very very precise temperature +/- a huge commissioning and field wiring error.
So if the hardware is the same, then the software must be different - nope.
|Ladder Logic Diagram|
Sure how you tell it what to do may be represented in a different "language" or via a different programming "paradigm", but what it does is it converts analog values into digital values and back again (ADC and DAC convertors), and in the middle bit it's all digital, so it does everything on the basis of sets of AND and OR gates (which many years ago was represented as "ladder logic" which was a visual analogy of a wiring circuit that related relays (digital states).
So where is the difference. Well sales technique counts for a lot (especially to the non-technical buyer), and then there are big words and euphemisms. So for example a BEMS is a euphemism for a BMS (a euphemy is simply the opposite of blasphemy - it literally means "speaking well")
Beyond sales technique there are the human skills of what to tell the computer (that's what it is) to do. And here there IS an enormous difference. You can either buy a set of pre-programmed modules off-the-shelf, or you can get someone to programme the "computer", that actually understand what boilers and air-handlers do. No they aren'tt light switches, boilers pre and post-purge, and no a PID is not a suitable solution for controlling a non-proportional response.
My tip to the energy manager, take the controls salesman into your plant room and ask him to explain what a sedimentation vessel achieves between primary and secondary circuits beyond the obvious (hint : hydraulic de-coupling of pumped circuits) . If he (or she) can't, then get someone who can - most local HVAC contractors can put someone in the frame to do the job.
And if your control system has to be configured by an "in-house expert" apply the same test and then say no - It is an artifical differentiator to suggest exclusivity and sucker byers with higher prices - that game went out of style a decade ago. the big-boys just have'nt all figured it yet.
Correction - some have - they call you cash cows - go and be assertive or go and be milked dry - the choice is yours !
If you think this article might help anyone or make them smile wryly - please do share it - and if you disagree and want to argue - I make mistakes - that's what the comments are for !