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Thread: SCADA System
10-01-2012, 01:14 PM #1
Can someone explain the differences between SCADA systems and your typical BMS such as a Continuum or a JCI system?
I know SCADA systems are typically used in industrial process, but why? Is it more reliable/ robust, can handle more points?
Do different manufactures have differing protocols such as proprietary, BACNet, Lon etc ? Can differing manufacturers communicate with each other?
Do you have the same signal choices, I.E., 0-10 VDC , 24 v etc.?
Are there any gotchas or any pitfalls one needs to look out for and or avoid that anyone can share.
What of network architecture? I.E. MSTP, IP, PTP?
I need to get up to speed on SCADA (purely on a design level) pretty quick and I have zero experience with it other than looking at a front end once or twice for CX purposes.
Thanks for any input.
10-01-2012, 09:07 PM #2
So know one here works with SCADA systems?
10-01-2012, 09:12 PM #3
10-01-2012, 10:48 PM #4
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10-01-2012, 11:21 PM #5
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10-01-2012, 11:40 PM #6
There too many differences to mention.
There is plenty of SCADA software in use in HVAC ... Johnson M5, Wonderware ...etc etc ... could run a steel mill with JCI M5 ( which is why MSEA is a backward step IMO)
It is often overkill for HVAC though ... we typically wont use batching, and redundant rollover...typically almost nothing happens at high speed like it does in SCADA world
You usually wont find thermistors in Scada, or 0-10Vdc ... in factory environments ...position encoders, stepper motor control, thermocouples, Platinum, 0-20mA, 4-20 mA etc yes.
In SCADA there are sometimes direct data connections to ERP, Batching, provisioning, ordering systems, and feed-forward info to other processes further down the line
In SCADA lots of stuff written in PLCs rather than relatively dumb and slow DDC controllers.
In SCADA buckets of Modbus, DDE, OPC rather than Bacnet, LON, N2
Most PLCs have their own special proprietary language as well as a version or 2 of modbus. Most SCADA packages know already how to communicate with the PLCs via built in drivers. Mostly all of this is "open" AND available for a price though not always cheap.
SCADA is often purchased on 'per-point' , 'per-driver' or 'per-tag' basis ... either way you pay quite a bit. The cost of software and drives is minuscule compared to the engineering of the product and fine tuning of the systems.
Unlike HVAC where the software is pretty cheap ... but kept under lock'n'key ... or 'managed' by special dealer-only arrangements.
the difference is mostly that SCADA needs precise, engineered input. HVAC ( to a point) can be managed by fridgies, sparkies and plumber.
Any pitfalls ??
yeah ... be careful
... stop the building cooling in HVAC and it just makes yr ears hurt because the phone rings incessantly until its fixed.
...stop the process line in a factory and it might cost $1m a minute until its fixed1 + 1 = 3 ( *** for very large values of 1)
...everybody wants a box of chocolates and long stemmed rose
10-02-2012, 09:07 AM #7
Thanks Matrix, that clears up a few things. The project that I need to bone up on is not for HVAC, it is for a waste water treatment plant expansion. They have a SCADA system in place that the new pumps, scrubbers etc. need to tie into. I don't need to program anything or otherwise get my hands dirty, so to speak. I just need to understand enough to put on a set of plans for a design build....not to say I would not want to understand more than the minimum necessary for what I am working on.