National Instruments executes on its simulate-to-test strategy

Seeing a company with an exciting top-level strategy is a wonderful thing. National Instruments has a brilliant strategy that is focusing on helping engineers. When National Instruments bought Electronics Workbench up in Canada, their brilliance was obvious to me. Electronic Workbench owns the college SPICE program market. So that is a cool strategy, exposing college kids to the products, like Apple does with Macs, but the real strategy was trying to build a company that can help us through the entire design, prototype, and testing of a product. Think about it. Wouldn’t it be wonderful if you could do a SPICE simulation on your circuit and the cool thing is that the simulation you did can also be used to craft a test program for real physical instruments? So after you layout the board and get it stuffed, you can then have a National Instruments test systems that is all waiting to do the same things to the real board that you did to the virtual board in Electronics Workbench. Brilliant, just brilliant. And note that National Instruments is making partnerships with Sunstone and Digi-Key to help you get the physical PCB made and stuffed. So when this is fully implemented, all you need is 4 companies to design, build, and test a complete electronic system. You draw, simulate, and layout the design with National Instruments, then have Sunstone make the board, and they send it over to their partner Screaming Circuits to get stuffed. Screaming Circuits will order your BOM (bill of materials) from Digi-Key. Then once you have the PCB all built, you connect the board to a National Instruments test systems that is working off the same setup you created in their SPICE package. Now you can excite the real board with the same signals as you did your SPICE circuit, and you can compare the real results to the simulated results you got from your SPICE runs.

I asked a National Instruments Bhavesh Mistry, a NI marketing manager, about this when I was at PCB West last year, and he was nice enough to send me a little write-up about what National Interments is doing for us engineers:

National Instruments has further integrated the worlds of PCB prototype design and validation with NI Multisim and the PXI hardware platforms. By integrating the recently released Multisim 10.1.1 circuit design software, with PXI test and measurement hardware, engineers can within a single environment simulate their PCB designs and then immediately compare to real-world prototype measurements. This type of quick, streamlined analysis is working to improve the traditional design flow through integration not previously available. Soon to be available at the ni.com/labs website are new beta versions of PXI measurement instruments that can acquire both simulated and real measurements.

Multisim makes it possible to interactively build circuit schematics and simulate circuit behavior in a highly graphical environment. Because Multisim abstracts the complexity of SPICE simulation, engineers do not need in-depth SPICE expertise to quickly capture, simulate and analyze new designs. With enhanced simulation, engineers experience fewer design errors and achieve a quicker prototype turnaround with fewer iterations.

Both simulation and physical prototyping play a fundamental role in the design flow, and with NI software and hardware, we can implement best practices through integration. The beta version of the PXI Measurement Instruments for Multisim, allow engineers to add new simulation analyses to Multisim. These instruments are intuitive, easy-to-use interfaces to visualize simulated data.

With a single flick of a switch, these same instruments can acquire both real and simulated circuit measurements to correlate and analyze circuits to reduce cost and development time with an improved, methodical approach to benchmarking prototype behavior. This new functionality is providing engineers with cutting-edge tools to increase productivity. Individual engineers can now quickly prototype their designs and then use simulated data to benchmark physical measurement performance.

Five new beta instruments will be available that connect to corresponding NI PXI hardware: DC-Variable Power Supply (NI PXI-4110), 2-Channel Scope (NI PXI-5122), HSDIO (NI PXI 6552), Digital Multimeter (NI PXI 4071), and an Arbitrary Waveform Generator (NI PXI-5422).

NI is continuing to invest heavily in the development of the Multisim product-line, with new version releases, innovative new tools available in beta form, and technical resources. Multisim 10.1.1 can be purchased as a complete, integrated design and test platform that includes the board layout and routing of the NI Ultiboard 10.1.1 environment. Multisim 10.1.1 is currently shipped in English, German and Japanese versions. Readers can download a beta version of the connectivity toolkit for free at www.ni.com/labs.

One thing to note is how well Electronic Workbench does the user interface for SPICE. Rather that insisting that you have a computer science degree and speak geek gibberish, typing the SPICE netlist from memory and then applying arcane commands like “.TRAN {print step value} {final time} [{no print time} [{step ceiling value}]] [UIC]”, Electronic Workbench got wildly popular in colleges because they decided to have their software speak the language of hardware engineers rather than force us to do geek-speak software talk. So first off, they don’t think of the SPICE net list as the primary thing, they think of the schematic that they derive the net list from as the primary thing. The brilliant thing about Electronics Workbench is that when you want to do an ac transient simulation, you go to a handy toolbar in the program and drag a spectrum analyzer from the bar onto your schematic. It is a virtual instrument that you plop down on the schematic. When you want to see the bode plot of a node, you just draw wires to the circuit node you are interested in, and then look at the results on the virtual instrument. The same goes for dc measurements with a multi-meter or time domain observations with a virtual oscilloscope that you wire into to your schematic. I see why college professors love Electronics Workbench. By doing a SPICE simulation, it teaches the kids what test equipment they will be using and where to hook it up.

Now do you get it? Now do you see why National Instruments’ Dr. Truchard is a genius? He bought Electronics Workbench and yeah, that is great to get NI in the college scene, but the real brilliance is that those little virtual instruments that you drag around in your SPICE simulation can represent real instruments that National Instruments makes. National Instruments has already integrated a lot of their PXI instruments into Electronics Workbench, so you will be setting up your SPICE runs with the exact same virtual front panel that the real PXI instrument has. So when you do all the SPICE work up front, you are also defining a test regime for your board. Your real PXI instrument will make a real stimulus just like the virtual stimulus they made in SPICE, and the real PXI instrument will gather results that you can just plop on top of your SPICE results to insure they match up.

Now I am not writing a hagiography, there are always downsides. One thing is that Electronics Workbench is a stitched-together environment like most CAD vendors. Their board program came from a Dutch company called ULTIBoard. Remember those goofy ads in EDN that showed a knight on a chessboard? That was ULTIBoard. Electronics Workbench bought them and the primary Dutch programmer moved to the EW home office in Toronto, so that is good, but I don’t know if the board layout part of EW is as sophisticated as Altium or PADS. I will tell you that as cool as all the SPICE and testing protocol stuff is, the most important part of your CAD package is the board layout. If it can’t do matched trace length if you need it to, if it does not let you make the thermal vias the way you need it to, well, that is a show-stopper. PCB layout is not so critical to the college market where EW rules, but it is critical to working engineers that need to get a board built.

Another limitation I ran into in EW four years ago involved an arcane SPICE simulation I was trying to run. I was trying to model the noise of an op amp circuit when the op amp model had no built-in noise equations. So I just put little current sources in the op amp input pins and a voltage source across the pins and then looked at those as the equivalent input noise generators. I was doing this in PSpice with Capture as the front end. So the deal was that to get an rms noise reading you have to integrate the noise over a bandwidth of interest. PSpice can do an integral on the output no problem, where EW could not; they had not added that feature to the program yet.

BTW, my buddy Martin Cano figured out the coolest thing about the PSpice run I did. The integral of the noise over bandwidth did not make sense in PSpice, it actually went down over some ranges of the frequency, and that is impossible, you can’t be integrating noise over added bandwidth and have the rms noise go down. I showed Cano, and he scratched his head and shrugged. By the time he walked back to his cube 20 feet away, he had the answer– the noise is a complex number– it has both phase and magnitude. So you have to take the integral of the magnitude, the absolute value of the noise. It was easy to do in PSpice, just write the formula in the plotting program. Once I took the integral of the magnitude of the noise, then the rms noise agreed closely with the flat-band noise of the real op amp. Of course, none of this would help you with 1/f noise, but I suspect that you could factor that into the current and voltage sources somehow. All I cared about was getting an rms noise approximation from an old-op amp model that did not have noise modeled inside it.

Seeing a brilliant top-level corporate strategy is a wonderful thing. Texas Instruments has one. They owned the DSP market, and so they bought Unitrode and Benchmarq to feed the DSP power. They bought Burr Brown to do the analog on the front and backsides of the DSPs. And way before this, they knew enough to let the DSP group flower after they used one in their Speak and Spell toy. I see Intersil doing brilliant strategy as well. They have a solid base of analog chips, then they bought Kenet to get fast ADCs, Xicor to get floating gate analog, Zilker Labs to get digital power, and D2 Audio for sound, which also got them fellow biker Skip Taylor, a great deal for any company.

I guess my message to other EDA companies is that you don’t have to watch Electronics Workbench take your customers away. Altium or PSpice or even the wonderful free LTSpice from Linear Technology’s Mike Engelhardt could have virtual instruments that you drag into the schematic to do SPICE. Rather than just NI instruments, they could be Agilent spectrum analyzers, and Tektronix scopes, and Keithley source meters and electrometers. This would teach you how to test the circuit at the same time as you figured out how to SPICE the circuit. One day I hope the CAD packages will allow the entry of the available test equipment on our lab bench and the parts over in the little Akro-Mills boxes in the tool crib. Then you could sit down at your computer, design with parts that you know are sitting in the lab, and do your SPICE simulation with virtual representations of the real instruments you happen to own. The coolest thing is that the SPICE program could factor in the bandwidth of the scopes and probes and such, to show you exactly what the real instrument would show, but the SPICE program could also warn you that the circuit was oscillating so fast that it is not showing up in the slow scope that you dragged into the schematic. Now that is SPICE we can all get behind.

Then any CAD program could work the way National Instruments does, with the design files going off to get the board made, the parts ordered and the board stuffed, all the while creating a test regime, maybe with a procedure for an unskilled technician to take the data. Oh, another cool thing about NI Electronics Workbench and Sunstone I forgot to tell you was that Sunstone will import their design rules into the Electronic Workbench board layout program so that you can’t design a board that Sunstone is incapable of making. Sunstone also does this with their free PCB123 program as well as with Altium and PADs. So there you have it, soon we will have computers doing all the drudgery and we can have all the fun. What a wonderful new world it is going be.