Hand - Off - Auto / Remote - SCADA Architecture Question *All You Super Users Read This*

[cmcgonag]

I am new to the forum. I have searched the net for almost 6 months on this and haven't really found a good response....

I have been around the block a few times with various control systems and am trying to figure out how to build a "proper" control system on the cheap. I used to use alot of Labview in School so that is how I ended up here.

What I want to do is have Hand Control at the Machine (Arduino Control System / or something) be able to switch that to Auto/Remote (Labview or some other language) then have that talk to SCADA (Thingspeak, SQL, havent figured this part out yet).

My question is how would you do it? I am a pretty good programmer and know just about every language so nothing is off the table. Seriously I would like to see some creative action.

I dont think LIFA is the best cause I need LOCAL control of all the variables. I would like to have PID loops etc running on the Arduino. I need to be controlling serial attached machines. I have some RS-485/232 going to VFDs and a dSPiN as well.

However, when I want to control it remotely, I would like to be able to pass set points if in auto mode or even better, in addition, be able to override auto and drill down into each attached component and control it in Hand remotely.

I know I could do this by building everything in VIs then linking through LIFA and using the VI as my hand/auto. However, I do not trust the link between LIFA and the Arduino that much. Also I do not know the capability of LIFA to do the RS-485 and serial data to the dSpiN. I need to be on Ethernet/Wifi, and if the controller goes down we may have a legitimate safety problem; hence why I want local control as my backup.

Further more how would you do the SCADA? I dont want to spend 4K on a Full Labview License.....I would prefer just using the iPad app and some free online services...I will  have a server running all the time as well.

If LIFA can be used to do some of this please let me know....Any links to past projects by people would be a huge help.

My Plan right now is:

Machine Data/Control sent to Arduino over RS-485 , 4-20ma and SPI.

Local Control on the Arduino. Local Arduino connected LCD displays Key Parameters.

Send Local Main Variables *Set Point / Run / Stop Etc / Key Data* over Serial or Hacked LIFA to Labview over ethernet or wi-fi.

Labview acts as main supervisory "go-between" and provides all main "in house" HMI support

Real time proccesing happens in Labview and is displayed on labview VIs; Realtime data is also sent out remotely over a service for world wide access.

Labview also sends all real time data to historical service of some kind either (web based or local based) (will be locally hosted)

Access historical data remotely by some means (API / Webservice)

Remote World Wide Access to Labview and thus machine, through Labview iPad app or VPN into house.

World Wide Historical Access through API or Webpage.

That is where I am at in my thinking. Please blow it up and make it better.

I appreciate y'alls help.

~Colin

[hrh1818]

Most readers here are amateurs  I suggest you try the main Labview discussion forum.

at <http://forums.ni.com/>

hrh1818

[Kristoff2]

Hey Colin,

It sounds like you are working on a rather large application (without a budget to match).  NI has lots of products that would make what you're asking easy.  Typically I would recommend using a cRIO as the main contorl unit with LabVIEW RT, LabVIEW FPGA and LabVIEW DSC to program the cRIO.  You could setup your control loops in FPGA, use DSC for remote access, logging and monitoring.  You can even host shared variables on the cRIO and monitor and control them via data dashboard on your iOS or android device.

Can you give a little more info on what exactly you are trying to setup and what you'll be controlling so we can get some idea of the scale, speeds, data bandwidth of this application.

Thanks!

-Sam K

LIFA Developer

[cmcgonag]

I have actually used a cRIO and RT and FPGA before. Took a class y'all gave in Houston about a year ago...cool stuff. Really liked it. I wanted a windows embedded machine back then but y'all didn't have them yet.

So my current project is a Chiller (refrigerator) it will be connected to a ABE reactor and possibly a gas to liquids plant. In my backyard. I travel for work so I need to control this remotely cause once you get it started you can't stop it. The flammable stuff I won't run unless I am home. Safety is a priority. All my systems have proper mechanical and hard electrical stops / reliefs. This control system is not responsible for safety.

I  Have purchased various things off of eBay. Have a baldor VFD. A stepper motor valve, and a bunch of RTDs and pressure transmitters. I have the valve up and running using a 30 dollar dSpin and the Baldor motor will be controlled off of modbus probably (haven't tried yet). RTD goes through a 4-20ma converter. Everything pressure/temp wise is 4-20ma.

Data rates are slow by your standards I only need updates every ten seconds or so. But would like every 1 second.

An arduino mega has enough bandwidth and inputs for my needs. Multiple tx/rx and analog inputs. So use that as your base.

I am extremely confident I can build what I want with cheap hardware. It will cost me time to do the software. I don't really see the need to spend 500 bucks on a cRIO 4-20module when I can build my own for ten in under an hour.

I Personally really don't like labviews GUI either. I want to write some HTML or OSC scripts and use interfaces I have for that. Labview appears to be very good at moving data around hence why I want to use it.

At the end of the day I want to be able to have an open source biological refinery I can give away to third world countries for energy production. Mechanical Hardware is dirt cheap. Control system to keep it running is 10x the mechanical cost. Hence why I am doing it on my own......this isn't a free energy idea or anything... It is just like brewing beer but instead of brewing beer you make sudo gasoline. I need be able to build these things cheap.....my current solution is way overkill to get the bugs worked out.