PLC Virtual Shared Memory using SQLBridge

How can you accomplish virtual shared memory between PLCs of different models or even different brands? For example, how can you share memory between Rockwell and

Siemens processors? And what problems would this solve?

The first thing I want to point out is that the solution is not complicated or expensive and very few people even know about it. Yet it's the simplest solution in the world and can be setup to work in just a few minutes. The solution, by use of SQL Bridge, simply involves mapping two transaction groups in the bidirectional update mode to the same table. That's all. Each transaction group maps to a single PLC. And did you know you can create additional transaction groups for many more PLCs configured in the same way and have all of them share the same memory? There's no limit in the number of PLCs that can partake.

All this can be configured from only the Ignition Gateway and Designer. You can even launch several Gateway clients and using the Quick Client monitor and manipulate address values in each of the PLCs simultaneously. Everything for configuration and testing in one program and at arms length. How simple is that?

Think of the problems solved. Some gnarliest problems I ever encountered as an integrator had to the with inter-processor communications and handshaking, particularly between different brands or models of PLCs. It usually got complicated. Just documenting all the communication paths and getting my head around them, especially when there were many different brands/ models of processors involved, was onerous. Usually hardware protocol converters were required and talk about a pain, ouch! Handshaking was unreliable and it seemed like communication would always stop at 2am in the morning...always. And none of this was really "shared memory" anyway. Not really.

What do I mean by shared memory? Simple... you change a value of an address in PLC "A" to 99 and a corresponding address in PLC "B" gets the same value of 99. Now if you change the same address in PLC "B" to 33, then the original address in PLC "A" now sees 33. This is the magic of the bidirectional mode. I call it bidirectional mirroring. It's the most useful thing ever for an integrator. A thousand uses. No one else would ever understand the value of this.

But it gets better than that. Transaction Groups are configured just by dragging and dropping browsed tags into them. There are just a few fields to fill out to make it all work and half of those are just dropdown or checkbox selections.

Experienced integrators know that shutting down any system during production is no good. That's why online programming was invented for PLCs. Well, it's the same with SQL Bridge. Need to make an online change? No problem - no need to shut anything down.

You only need the SQL Bridge module and the zero-cost platform all at a price which is ridiculously low. You might want some OPC drivers too but they are equally low cost. I think the pricing committee lost their minds!

Virtual Shared Memory is just one thing out of 1000 things you can do with SQL Bridge. SQL Bridge was my secret weapon when I was an integrator. Now it's yours. Enjoy!

The PLC Industry is about to be Disrupted by a Source you would Never Expect

Bedrock Automation.  Never heard of it?  That’s probably because they've come swinging out of

Silicon Valley where anything is possible.  In two short years they've built a cyber secure PLC with OPC-UA built-in.  The operating temperature rating  is -40℃ to +80℃.  

All power and communications through the backplane is completely pinless by use of  what they call Black FabricTM  technology.  Not a single pin!

Their goal is to have as few catalog numbers as possible (they stated to me no more than a dozen part numbers).  For example, there is a single module part number for a universal I/O module.  By software configuration alone you can choose any type of industrial input or output, discrete or analog, AC or DC.

I held this thing in my hand and I've never seen or felt anything like it.  It’s rugged!  It’s well built!  I was even told they tried to blow one up by putting it on top of a million volt Tesla coil but it kept working.  

I know you’re thinking by now they’re just a flash in the pan.  But I don’t think so.  They are a subsidiary of Maxim Semiconductor.  Maxim has a 7.57B market cap and 8,800 employees.  A brief description of the company follows:

“Maxim Integrated Products, Inc. designs, develops, manufactures, and markets various linear and mixed-signal integrated circuits worldwide. The company also provides a range of high-frequency process technologies and capabilities for use in custom designs. It primarily serves automotive, communications and data center, computing, consumer, and industrial markets. The company markets its products through a direct-sales and applications organization, as well as through its own and other unaffiliated distribution channels. Maxim Integrated Products, Inc. was founded in 1983 and is headquartered in San Jose, California.”

The real question is, will they be able to push this amazing product to the finish line?  If they can actually deliver the product at the price point they told me, which is about the price of a mid-range PLC, then the price won’t be an obstacle.  In terms of hardware, I think it’s already a slam-dunk. Probably what it boils down to now is software.  And for that, I think they have some very cool stuff up their sleeve.

Their choice to build-in OPC-UA is a masterstroke.  While incumbents wearily cling to “has been” protocols, Bedrock is pulling out into first place with its UA adoption.  Welcome to the 21st Century!

Disruption happens when you least expect it.  Frankly, I was shocked to see what Bedrock has accomplished in so little time.  But Silicon Valley moves at a different pace and this company has significant resources.  Commercial release is slated for mid-2015.