how scada works???

hi,
i m monitoring a plant.
i came to know about SCADA and CITECT.
but i don't how they work?

i came to know about SCADA and CITECT.

Click to expand...

CITECT is a SCADA package. SCADA is a general term meaning Supervisory Control And Data Acquisition, while CITECT is both a company and a product which performs SCADA functionality.

but i don't how they work?

Click to expand...

For this I can give you but one good solution: read the manual. With CITECT it's all incorporated in the help.

All SCADA and HMI software essentially works the same way. You create objects, like digital displays or indicators or pushbuttons and place them on the screen. You assign a PLC register to the object either directly or through a tag base - a database of registers that are associated with a tag or device designation. The software's communications driver then periodically communicates with the PLC through a comm link and reads data from or writes data to the assigned register, and displays the results on the screen.

SCADA = Slow Control And Delayed Action

Ooh Old Timer. Used a serial connection did we. My latest project with Citect had Citect kernel reporting 15,000 digital reads per second. Used a good comms system with the PLC. Monitoring frequency for trending every 0.2 second.
beerchug

I am over 50 but attempt to learn things as much as I can.

SCADA=Slow Control and Delayed Action is TOO OLD. If you havent dealt with and learned NEW systems then you should not respond.

Changes, upgrades, new versions..etc..etc.. are made virtually daily. YES, its hard to keep up with.

THATS the point, many of us are old timers BUT dont want to keep thinking OLD WAYS.....NOT all of us are willing to accept that our kids are smarter and can do more.

Old Timer: Do you realize that NOW Scada systems can use Ethernet communication to transfer data? In some cases this can be 100mbs, 10 at the low end. Thats a long way from the old days at 300 baud. IT AINT SLOW.

For what it is worth I would like to add that the terms SCADA and HMI, although meaning essentially the same thing, have also developed different usages.

The generic HMI term is most often used where the main PC server is sitting directly on a network, (Ethernet, DH+, Modbus+...etc) that exchanges data at decent speeds.

On the other hand I prefer to use the term SCADA for wide area telemetry networks, usually radio modems that due to their much lower bandwidths tend to use different messaging strategies, such as "report by exception"..etc.

By this usage then...SCADA systems do tend to be slow and delayed...so Old Timer can extract some dignity from under what has been heaped upon him.

Thanks gents for commenting on my humor, or humour. Phil and I have similar outlooks, there is an implicit distance component of SCADA. Quantifying, distance means > 1 km, up to 1000's of km.

My customers tend to be remote mines, dams, pumping sites, pipelines unreached by high speed data infrastructure. We use ethernet on copper or fiber within the site, and spread spectrum ethernet radio within a few km.

Larger distances to sites, usually have to trade off speed for distance. Of course, response depends on the application, how much data needs to be sent and received per unit time.

For human Y chromosome carriers, >=50 years is merely advanced adolescence.

Regards,

Al

Hey Bobb, what PLC system and com's backbone did you use on you job. Sounds pretty good.

Technically I disagree with most of the explanations on what HMI and SCADA are except for Tom's.

The original question was about SCADA and Citech and how it works.

Simple overview of SCADA is its a PC program that has control over the PLC registers...ie what you put in is what the plc uses.

Example: If you are making BREAD and its set to use 5 pounds of flour but you want it to use 6 then you can change it...thats Supervisory control

SCADA programs like Citech also have Data Acquisition capabilities..ie if making BREAD it can tell you how much flour, milk, water, salt etc was used in EACH BATCH over a designated period. How much BREAD was made. How much downtime...you define what you want/need to know.

HOW does it do this? By being connected to the PLC...the connection can be in many ways depending on the PLC...ie can be serial, RS422/485, DH485, Modbus, Profibus, Ethernet...the list goes on. Connection type and distance are relevant to speed. SCADA has the option of using RTU (remote terminal units) which may be dialup/modem (and can be slow).

A search on this site and the NET for SCADA will give you an abundance of info.

Sleepy Wombat - the PLCs are 5 Omron CS1 with 10 Device Net scanners and 90 odd Device Net I/O blocks, 7 AB Powermonitor 3000.
The comms bacbone is Omron Controller Link.
The SCADA is Citect with a Controller Link card in the computer.
Citect also communicates with the fire panel via Modbus RTU and Alerton DDC controllers via Cimetrics BACnet OPC server.