Project with massive number of analog inputs

ceilingwalker

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Hello All.
I have a project that is pretty easy however, it involves over 1,000,000 analog inputs. It is a solar panel farm that has 200 inverters, that contain 25 panels each. The customer is requesting Allen-Bradley products, however it is designed. I have never worked with this much I/O in the past and I am hoping someone here has. I am not even sure I want to use a PLC here, since it isn't going to be controlling anything, merely reading data. I am not sure which SCADA system would be best, with this many tags. A one-minute sample rate is all they are requesting. Any and all advice would be greatly appreciated.

Thank you for your time.
 
Don't let the size get to you. You have to divide and conquer on this one.

Start by finding if the panels are split in some sort of logical way. That can give you a number to divide that 1,000,000 with.

Then take that number along with your sampling rate and see what kind of IO systems you have in the market and what is their limit. This will let you know your number of cells you'll have to create.

Eventually these will communicate with servers/HMI to process.

I was just yesterday looking for IO that could interface directly with a SCADA system and this sounds like something that would be of interest to you too...

Definitely contact a couple of brands to see what they have available.
 
Part of my work involves wind farms and it's very similar. First, I would get some clarification from the project team. In majority of the cases, they will already come with proprietary PLC/controller and sometime their own historian/SCADA software. i would be very surprised if they make you "roll-your-own".

The approach to these type of installation is similar, however:

Each "package", which can be a pack of solar panel/transformer got:

IO > IO interface/Controller > Local Server/HMI/Historian (optional) > Wide area SCADA > Wide Area historian (optional).

So, each "package" would be the same which can be hundreds of IOs. Once you get that done then just duplicate that design.
 
How have they done it in the past? they just completed one not that for from me and they are on the second, I would say they are about 100 acres in size

https://sccommerce.com/news/press-r...blishing-solar-power-operations-saluda-county

· A 6.8 MW facility in Saluda to be developed and operated by Saluda Solar I, LLC along with financing partner Cypress Creek Renewables

· A 3.4 MW facility in Saluda to be developed and operated by Saluda Solar II, LLC along with financing partner Cypress Creek Renewables
 
This definitely sounds like something you'd let AB engineer for you. The price point for that IO count should get you some pretty good service/support directly from AB.
 
I would imagine it will be a lot like what you are doing. However, this farm does not currently have any SCADA, which is why I was called in. To compare it to your situation, each of inverters would equal (kind of sort of) one of your "fans"......maybe. Each inverter has a string of 25 solar panels connected to it. I was thinking 1 PLC per inverter, when one inverter may go offline, it won't affect the other, and then tie all of the PLC's into 1 SCADA. A PLC may not be the best way to go here however, the customer has brought up many times that he wants Allen-Bradley used.
 
How have they done it in the past? they just completed one not that for from me and they are on the second, I would say they are about 100 acres in size

https://sccommerce.com/news/press-r...blishing-solar-power-operations-saluda-county

· A 6.8 MW facility in Saluda to be developed and operated by Saluda Solar I, LLC along with financing partner Cypress Creek Renewables

· A 3.4 MW facility in Saluda to be developed and operated by Saluda Solar II, LLC along with financing partner Cypress Creek Renewables

My information is limited however, this farm (location unknown) has 200-1.5MW inverters and currently has no data collection, as unreal as that may sound. For security reasons, I know very little and little is shared with me.
 
Processing power for 1 million analog inputs is going to be beyond the capacity of any single PLC, this cries for a DCS. But to cardosocea's point, it will still need to be a "divide and conquer" topology. An A-B PlantPAX DCS system comprised of multiple CLX processors off-loading the number crunching of the AIs would be a good solution if they want A-B.
 
A PLC may not be the best way to go here however, the customer has brought up many times that he wants Allen-Bradley used.

I have installed a few data acquisition systems that were just monitoring temperature, humidity etc with alarms but they did not have much on the control side other than alarms and nice graphics... they were standalone systems, its was a medical building and they did not want a PC running a HMI/SCADA

Has your customer done it in the past? if yes ask if you can go and see one of their systems
 
This sounds like an interesting project.

You can assign up to 4000 analog points to a ControlLogix processor, so that means you'll need at least 250 of them. I'm back-of-the-napkin-thinking here, so what seems reasonable to me is consolidating a panel (or a few) full of processors and using remote racks connected over Ethernet/IP to distribute I/O and reduce sensor wiring costs.
 
Last edited:
Don't let the size get to you. You have to divide and conquer on this one.

Start by finding if the panels are split in some sort of logical way. That can give you a number to divide that 1,000,000 with.

Divide and conquer sounds like the right approach to me. You could use small PLCs (probably micrologix or micro800 in the AB world) as data concentrators. Each PLC can cover a region of the farm, and gather all the inputs to serve up to the SCADA layer.

I like the IDEA of IO connected direct to Scada, and something like Modbus TCP may be the way to go there. I don't know if 1 million connections from the SCADA server is really feasible, though. Then again, I don't get involved with Scada nearly as much. Another poster suggested layers of SCADA, and that may be the way to go, with smaller SCADA acting as a data concentrator.
 
Can use things like Armor block IO or Ethernet Flex IO and Point IO. But I would not try to collect it all into one Historian. I would use multiple Historians and then use one Vantage Point server to display the data. Definitely get in touch with AB networking and Software groups. They have some forms you can fill out and they will do an engineering review and work with you on a solution.

I just did that with them for a large system with 15 PLC's and about 200 VFD's and 48 Thin Client FTView's.
 

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