DFT Plugin Added to Zuken Design Suite

Zuken  and XJTAG have entered into a partnership to enhance Zuken’s CR-8000 with a design for test (DFT) capability that will improve test coverage during schematic entry. The capability is based on XJTAG’s DFT Assistant, and will be available later this year as a free plugin for Zuken’s CR-8000 Design Gateway users. CR-8000 is a native 3D product-XJTAG-DFT-Assistant-768x435centric design platform for PCB-based systems. CR-8000 directly supports architecture design, concurrent multi-board PCB design, chip/package/board co-design and full 3D MCAD co-design. CR-8000 Design Gateway is Zuken’s platform for logical circuit design and verification.

Increasingly, PCBs are densely populated making it difficult to gain manufacturing test access to pins under many packages, such as ball grid arrays (BGAs). JTAG was designed to enable test access, so an optimized JTAG design can have a positive impact on ROI. Failure to optimize JTAG test coverage at an early design stage can increase manufacturing costs and possibly require a board re-design. XJTAG DFT Assistant will help to validate correct JTAG chain connectivity while displaying boundary scan access and coverage onto the schematic diagram through full integration with CR-8000 Design Gateway.

Zuken | www.us.zuken.com

DC-DC Conv. Does ±1% Voltage Regulation

Vicor has extended its family of isolated, regulated DC-DC converter modules (DCMs) in ChiP packages, by adding a range of ±1% voltage regulation devices. With unrivaled power densities of up to 1,032 W-per-sqaure-inch, the new series will offer engineers the option of directly driving loads that require tightly regulated output voltages. Vicor’s current family of DCMs in a ChiP package offers up to ±3% regulation and can also be paralleled into arrays for higher power delivery.

ChiP-DCMThe ChiP DCM can operate from a wide range unregulated input to generate an isolated DC output. With its high frequency zero-voltage switching (ZVS) topology, the DCM converter consistently delivers high efficiency across its entire input voltage range. The new series of DCMs are initially offered with 28 V, 270 V, and 275 V nominal input voltages. These products are aimed at a variety of defense and industrial applications that require tighter output voltage regulation – applications including, UAV, ground vehicle, radar, transportation and industrial controls. These parts are available in M-Grade, which provides operation down to -55°C.

Vicor | www.vicorpower.com

Electrical Engineering Crossword — October (327)

The answers to Circuit Cellar 327‘s crossword are now available.327 Crossword grid (key)

Across

1. FIRMWARE—Executable software stored within a ROM
4. INFINITE—An incalculable number that extends indefinitely
5. ZENER—PN-junction diode designed to operate in the reverse-bias breakdown region
9. NETLIST—File that lists all connections needed to produce a PCB
11. ENCODER—Device used to encode a signal or character from one format to another
12. OCTAL—Number system based on powers of eight
14. PITCH—Nominal distance from center to center of adjacent pins or leads
17. BASIC—Beginner’s All-purpose Symbolic Instruction Code
18. LASER—Light Amplification by Stimulated Emission of Radiation
19. REGISTER—Storage space on a processor that holds an instruction, an address or data
20. WAVELENGTH—This is equal to the velocity divided by the frequency

 

Down

2. WAFER—Slice of semiconductor material upon which monolithic ICs are produced
3. JUMPER—Short length of wire used to complete a circuit
6. EXECUTABLE—File containing object code that’s ready for executing
7. NIBBLE—Four consecutive bits. Half of a byte
8. BREAKPOINT—Used in debugging programs A location to stop executing program code.
10. TRANSCEIVER—Circuit that Transmits and Receives a signal on the same line
13. COMPILER—Software that translates high-level language programs into machine-language instructions
15. HEAP—Area of memory used for dynamic memory allocation
16. RECURSIVE—A characteristic of software that calls itself

New Version of Altium Designer Previewed

Altium has completed an exclusive preview tour of its Altium Designer 18 at a series of upcoming global PCB design conferences. Altium Designer continues its focus on delivering new, easy-to-use and productivity enhancing PCB design tools as part of a single, unified application. Leveraging feedback and suggestions from the design community, Altium Designer 18 features capability updates and performance optimizations to significantly enhance user experience and productivity. In addition to the easy-to-use, modernized user interface, Altium Designer 18 will also feature a much anticipated upgrade to 64-bit architecture and multi-threading for greater stability, speed, and functionality. These updates will allow designers to increase their design speed and task execution, and also provide more flexibility and control, simplifying the overall design process.

Fast and High-Quality RoutingThe Altium Designer 18 release significantly enhances user experience and productivity with a modern interface to simplify the design experience and enable unprecedented performance optimization, aided by 64-Bit architecture and multi-threading for greater stability, speed, and functionality during PCB design.

Connectivity management and enhanced 3D engine allows you to render design models and multi-board assemblies – faster and with better shading and realism. Real-time BOM management in Altium Design 18 links the latest supplier part information to the BOM, enabling users to make educated design decisions on their own timeline. A new, cohesive user interface provides a fresh and intuitive environment, and optimizations that enable unparalleled visualization of your design workflow. Fast and high-quality routing is provided by visual Constraints and user-guided automation. These enable you to route complex topologies across layers. In other words, it routes at the speed of a computer, but the quality of a human.

Altium | www.altium.com

Tuesday’s Newsletter: Microcontroller Watch

Coming to your inbox tomorrow: Circuit Cellar’s Microcontroller Watch newsletter. Tomorrow’s newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

LX2160AAlready a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Microcontroller Watch newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

IoT Technology Focus. (11/21) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(11/28) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (12/5) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

LLC Controller With < 40mW Standby Power

Texas Instruments (TI) has introduced an inductor-inductor-capacitor (LLC) resonant controller with an integrated high-voltage gate driver that enables the what TI claims is the industry’s lowest standby power, as well as longer system lifetimes. The UCC256301 provides a cost-effective system solution that helps meet stringent energy-efficiency standards for a wide range of AC/DC applications, including digital televisions, gaming adapters, desktop computer and notebook adapters and power-tool battery chargers.

UCC256301The first in a family of new high-performance LLC controllers, the UCC256301 enables standby power of less than 40 mW when fully regulating the system output, while also performing better than industry efficiency requirements. By delivering the fastest transient response plus robust fault-protection features such as zero current switching avoidance, the device enables reliable operation over end-equipment lifetimes.

Key features and benefits of the UCC256301:

  • High efficiency and lowest standby power: By achieving a new low in standby power, the controller exceeds Code of Conduct (CoC) Tier 2 and U.S. Department of Energy (DoE) Level VI efficiency standards and achieves more than 90% efficiency with a 10% load.
  • Faster and more stable system transient performance: Hybrid hysteretic control, a new patented control method from TI, enables up to 10 times faster transient response and reduces output capacitance by 20 percent, leading to faster system response times.
  • Extended system lifetime: Robust fault-protection features on the device, such as zero current switching avoidance, extend system lifetimes.
  • Simplified design: Engineers can easily design their systems with the integrated X-capacitor discharge and high-voltage startup features.

The UCC256301 is the latest addition to TI’s high-voltage portfolio of end-to-end power-conversion solutions delivering high efficiency. In addition to the UCC256301, the new portfolio of LLC controllers includes the UCC256303, which works easily with an external bias, and the UCC256304, which supports wide input ranges. Engineers can pair the UCC256301 with a TI power factor correction (PFC) controller and synchronous rectifier (SR) controller to increase system efficiency. To meet a variety of power levels, PFC controllers include the UCC28180, UCC28063, UCC28051 and UCC28070. The UCC24610 SR controller can also be paired with the UCC256301 to further improve efficiency.

Support tools for the UCC256301 to speed engineers’ time to market include the UCC25630-1EVM-291 evaluation module, WEBENCH Power Designer and SIMPLIS transient models. Engineers can jump-start high-voltage system designs using the UCC256301 with the 480 W AC/DC Industrial Reference Design and 450 W AC/DC Reference Design with Single-Layer PCB.

Texas Instruments | www.ti.com

Cadence Adds Real-Time DFM PCB Design

Cadence Design Systems provides Cadence Allegro PCB DesignTrue DFM technology that performs real-time, in-design design-for-manufacturing (DFM) checks integrated with electrical, physical and spacing design rule checks (DRCs). The technology, integrated into the Allegro PCB Editor, enables PCB designers to identify and correct errors immediately, long before manufacturing signoff. By finding errors earlier, design teams reduce rework, shorten design cycles and accelerate the new product development and introduction process, potentially saving at least one day per iteration and days to weeks overall.

Cadence originalUnlike manufacturing signoff tools that are run in batch mode when performing DFM checks, DesignTrue DFM technology provides continuous in-design feedback while designing, eliminating the frustrating and time-consuming design-verify-fix iterations between PCB designers and DFM checking teams. By the time PCB designers reach final DFM signoff, they already know their design meets manufacturing rules, resulting in a smoother signoff and handoff to the manufacturing partner and a shorter, more predictable design cycle.

Introduced in September, DesignTrue DFM technology is consistent with the proven Allegro constraint-driven design flow and online checking solution currently used for electrical, physical and spacing rules. DesignTrue DFM technology provides a wide set of checks to ensure design manufacturability. Spacing between copper features such as traces, pins, vias relative to the board outline and other copper features can be verified in real time, independent of electrical and net-based rules.

The new technology makes it easy to configure, apply contextually and reuse manufacturing rules. DesignTrue DFM technology supports the import and export of DFM rules and addresses more than 2,000 advanced checks. In addition, it employs a new and more user-friendly DRC browser capable of addressing one class of errors at a time. Constraints are highly configurable with the ability to enable and disable groups and whole categories of rules, or individual rules. Rules can be applied in etch mode, non-etch mode, and in stack-up mode, giving designers the ability to isolate layers, geometries and cutouts. The new browser also features an integrated DRC description with graphics, characterizes DRCs by type and provides a DRC count chart. Users can quickly sort, browse and review, as well as waive and unwaive DRCs.

Cadence Design Systems | www.cadence.com

Negative Feedback in Electronics

Lead Image Novacek

A Look at the Opposite Side

Besides closed-loop control systems, negative feedback is found in many electronic circuits—especially in amplifiers. And just like positive feedback, negative feedback can significantly change or modify a circuit’s performance.

By George Novacek

Following last month’s discussion of positive feedback, let’s now take a look at its opposite: the negative feedback. Besides closed-loop control systems, it is found in many electronic circuits, especially in amplifiers. As we have already seen, feedback significantly changes or modifies a circuit’s performance. The end of the 19th century and the beginning of the 20th century was the era of introduction of the telephone. For long distance calls, amplifiers were needed along the telephone lines to make up for their transmission losses.

Vacuum tube amplifiers of the day suffered from many ailments: drift, high distortion and generally poor performance, making the long-distance voice communications nearly unintelligible. Harold Stephen Black, an AT&T engineer, was one of many working to solve this problem. Eventually—because he was familiar with the effects of negative feedback in mechanical systems—he tried to apply it to a vacuum tube amplifier. The result was astonishing and amplifiers with negative feedback have been with us ever since.

FIGURE 1 Transfer function of an operational amplifier with negative feedback

FIGURE 1
Transfer function of an operational amplifier with negative feedback

The op amp is the epitome of feedback application in electronic circuits. Because its comprehension is valid for all electronic feedback circuits, let’s take a closer look at the op amp. To analyze the negative feedback mathematically, we’ll consider an amplifier as a combination of two functional blocks: The open loop gain (OLG) block with transfer function A(s) and the feedback block with transfer function β(s). With monolithic amplifiers, the feedback is usually applied externally. The overall transfer function follows the principle shown in Figure 1.. …

Read the full article in the November 328 issue of Circuit Cellar

Don’t miss out on upcoming issues of Circuit Cellar. Subscribe today!
Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

3.5″ SBC Serves up Skylake Processors

COMMELL has announced its LS-37K 3.5-inch embedded mini-board based on Intel 6th/7th generation FCLGA1151 Skylake / Kaby Lake Core processor family and Xeon E3-1200 v5 processor. The Skylake PC is claimed to deliver 30 percent better performance than a PC base on Ivy Bridge architecture, 20 percent better performance than a PC based on Haswell, and 10 percent better performance than a Broadwell PC.

LS-37K-3D8The LS-37K desktop 3.5-inch mini-board platform supports DDR4 memory DIMM 1866/2133 MHz up to 16 GB. The platform is based on Intel HD530 (Skylake) HD630, (Kaby Lake) and HD P530 (Xeon E3-1200v5). For graphics, the Skylake GPU offers 24 execution units (EUs) clocked at up to 1150Mhz (depending on the CPU model). The revised video engine now decodes H.265/HEVC completely in hardware and thereby much more efficiently than before, and HD Graphics 630 GPU is largely identical to the 530 found in Skylake, The only real upgrade here is the HEVC and VP9 support. LS-37K Displays can be connected via 1 VGA, 1 LVDS, 1 DVI, 1 HDMI and one DP port, up to three displays can be controlled simultaneously.

LS-37K offers lots of features including high-speed data transfer interfaces such as 4 x USB3.0 and 2 x SATAIII, equipped with dual Gigabit Ethernet (One of the dual LAN with iAMT 11.0 supported), and comes with PS/2 port, 5 x RS232 and 1 x RS232/422/485, 4 x USB2.0, Intel® High Definition Audio, and 1 Mini PCIe socket (supporting mSATA) and 9 to 30 VDC input.

COMMELL | www.commell.com

PCB Technology Leadership Awards

Mentor has announced its 27th annual PCB Technology Leadership Awards. Started in 1988, this program is the longest running competition of its kind in the electronic design automation (EDA) industry. It recognizes engineers and designers who use innovative methods and design tools to address today’s complex PCB systems design challenges and produce industry-leading products.

Prominent experts in the PCB industry judged entries from around the world in categories that represent a wide variety of industries:

  • Computers, blade and servers, memory systems
  • Industrial control, instrumentation, security and medical
  • Military and aerospace
  • Telecom, network controllers, line cards
  • Transportation and automotive

The PCB Technology Leadership Awards contest was open to any designs created with Mentor PCB solutions. Judging is based on design complexity and overcoming associated challenges, such as small form factor, high-speed protocols, multi-discipline team collaboration, advanced PCB fabrication technologies, and design-cycle time reduction.

The expert judges included Michael R. Creeden, San Diego PCB CEO and founder; Gary Ferrari, FTG Circuits technical support director; Rick Hartley, RHartley Enterprises principal engineer; Steve Herbstman, SHLC founder and lead designer; Happy Holden, Gentex Corporation (retired); Andy Kowalewski, Metamelko LP senior interconnect designer; Pete Waddell, president of UP Media and publisher of Printed Circuit Design & Fab/Circuits Assembly Magazine; and Susy Webb, Fairfield Nodal senior PCB designer.

2017 Technology Leadership Award Winners
Category: Best Overall Design

  • Company: Fujitsu Augsburg
  • Design team: Simon Czermak, Michael Schreittmiller, Sergej Beljaev, Andreas Titz, Mario Lanteri, Markus Wicher, Werner Hasubick, Peter Bräu, Nikola Skordev, Dieter Feiger
  • Using: Xpedition Enterprise
The best overall winner of the 2017 Mentor PCB Technology Leadership Awards is the team from Fujitsu Augsburg for their design of a high-performance computing mainboard. (PRNewsfoto/Mentor, a Siemens business)

The best overall winner of the 2017 Mentor PCB Technology Leadership Awards is the team from Fujitsu Augsburg for their design of a high-performance computing mainboard. (PRNewsfoto/Mentor, a Siemens business)

Category:  Computers, Blade & Servers, Memory Systems

  • 1st place: Adcom
  • Design team: Moshe Frid, Alon Kukuliansky, Nitzan Habler, Eli Moshe, Haim Anava, Doron K’Eliyahu, Lior Elgazar
  • Using: Xpedition Enterprise
  • 2nd place: ASELSAN
  • Design team: Ahmet Erol, Fulya Ağirnas, Fatih Say, Emine Özer Türkay, Mustafa Algan
  • Using: Xpedition Enterprise

Category: Industrial Control, Instrumentation, Security & Medical

  • 1st place: Shenzhen Mindray
  • Design team: Hupeng, Ouyangyilong, Zhaoguolong, Yiyong, Suchaoxun
  • Using: Xpedition Enterprise
  • 2nd place: Murrelektronik GmbH
  • Design team: Matthias Haak, Simon De Serra
  • Using: PADS

Category: Military & Aerospace

  • 1st place: Curtiss-Wright
  • Design team: Ashleye Soanes, Pascal Sauvé, Luc Bouchard, Stephen Reich
  • Using: Xpedition Enterprise
  • 2nd place: Thales Alenia Space Italy
  • Design team: Enrico Checchi, Gabriele Rocco, Giovanni Saldi
  • Using: Xpedition Enterprise/li>

Category: Telecom, Network Controllers, Line Cards

  • 1st place: Altice Labs
  • Design team: Alfonso Figueiredo, Carlos Monica, Victor Soares, Luis Tavares
  • Using: Xpedition Enterprise
  • 2nd place: Coriant Oy
  • Design team: Sauli Kunnas, Peter Kokko, Hannu Saarikoski, Paavo Perälä, Sami Jokinen, Juha Sarapelto, Jyrki Vuorinen, Jycke Sulka-aho, Matti Pulkkinen, Jyrki Nyyssönen, Päivi Vallin, Juha Ahvenainen
  • Using: Xpedition Enterprise

Category: Transportation & Automotive

  • 1st place: Yanfeng Visteon Electronics Technology (Shanghai) Co., Ltd
  • Design team: Yuan Li, Yan Xue, Tao Wang, Qin Li
  • Using: Xpedition Enterprise
  • 2nd place: Sienna Ecad Technologies Pvt Ltd
  • Designer: Krishna Murthy BS, Raghava Charyulu V, Savita R Ganjigatti
  • Using: PADS

Mentor |  www.mentor.com

Tuesday’s Newsletter: Analog & Power

Coming to your inbox tomorrow: Circuit Cellar’s Analog & Power newsletter. Tomorrow’s newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

oki-78sr-12-prAlready a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Analog & Power newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Microcontroller Watch. (11/14) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (11/21) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(11/28) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Low Power PC/104-Plus SBC has Rich I/O

Winsystems has announced Its new PPM-C412 series for demanding environments and applications. It offers a broad spectrum of I/O features and the ability to expand functionality in a densely populated, standalone SBC solution. The board delivers greater performance and a clear upgrade path for current PPM-LX800 users while providing full ISA-compatible PC/104-Plus expansion.

WinSystems_PPM_C412At the heart of the board is a Vortex DX3 System on Chip (SOC), which offers a 32-bit x86 architecture with a dual-core microprocessor. The PPM-C412 incorporates dual Ethernet ports coupled with four serial ports, four USB channels and an LPT port for myriad communications options. It also includes dual simultaneous display outputs, one LVDS and one VGA, for Human Machine Interface (HMI) displays. Further, It provides 24 GPIO for monitoring and control, resulting in an I/O-rich, rugged SBC occupying minimal space. The PPM-C412 can be used on its own or in combination with the PC/104-Plus bus to expand functionality and capitalize on its full ISA compatibility, averting the need to re-engineer system architectures.

The PPM-C412 is specifically built for rugged industrial environments, with low power requirements, up to 2 GB RAM and an operating temperature range of -40ºC to +85ºC. With a 10-year availability, this new SBC also extends the product life of systems using commercial off the shelf (COTS) and proprietary PC/104 expansion modules.

Winsystems I www.winsystems.com

Gumstix Adds NXP SCM-i.MX 6D/Q Support

Gumstix, a provider of design-to-order embedded boards, has announced the release of the NXP Semiconductor SCM-i.MX 6Quad/6Dual Single Chip System Module (SCM) to the Geppetto D2O design library and the Gumstix Cobalt MC (Media Center) development board. The NXP SCM-i.MX 6D/Q [Dual, Quad] Core SCM combines the i.MX 6 quad- or dual-core applications processor, NXP MMPF0100 power management system, integrated flash memory, over 100 passives and up to 2 GB DDR2 Package-on-Package RAM into a single-chip solution.

QWKS-SCMIMX6-REVCEmbedded systems developers can, in minutes, design and order SCM-powered hardware combining their choices of network connection, communication bus, and hardware features. During the design process, users can compare alternatives for features and costs, create multiple projects and receive complete custom BSPs and free automated documentation. Designers can go straight from a design to an order in one session with no engineering required.

The NXP SCM is equipped with a wide range of I/O, multimedia processing, and connectivity features. Condensing it, a feature-rich power management IC and over 100 passive circuit elements into a single package, the SCM-i.MX 6Quad/6Dual greatly reduces the SoC’s cumulative footprint. The feature-rich Gumstix Cobalt MC single board computer shows off some of the best multimedia features of the NXP SCM with CSI2 camera, native HDMI, and audio, and connects over Gbit Ethernet, Wi-Fi and Bluetooth. The Gumstix Cobalt MC source description is available in Geppetto for any Geppetto user to copy and modify the board to meet their specific device requirements in minutes.

Gumstix | www.gumstix.com

STMicro and Objenious Collaborate on IoT LoRa Network Deal

STMicroelectronics and Objenious are working together to accelerate the connection of IoT nodes to LoRa networks. ST’s development kits certified on the Objenious network are available now, greatly reducing R&D effort and time to market in the creation of new LoRa devices.

STM32 Nucleo LoRa kits are now certified and available to developers through ST sales channels.

STM32 Nucleo LoRa kits are now certified and available to developers through ST sales channels.

LoRAWAN is a Low Power Wide Area Network (LPWAN) based on LoRa technology that is opening up a world of possibilities to create networks of connected devices ideal to address a broad range of IoT applications. The benefits of LoRa especially suit applications where nodes have limited power capability, can be difficult to access, and data transfers don’t require high bandwidth. LoRa can target a wide spectrum of applications such as tracking, proactive maintenance, and many others. Industry analysts estimate there will be tens of billions of connected devices deployed in the world by 2020.

Objenious launched and operates the first LoRa network in France, with more than 4,200 antennas deployed around the country. Leveraging the network know-how inherited from Bouygues Telecom, Objenious now proposes its LoRa network, platform, and services for LPWAN IoT to partners and customers locally and internationally thanks to roaming agreements.

STMicro helps developers by providing tools and software libraries that aid the STM32 MCU-based embedded design as part of its freely available STM32 Open Development Environment (ODE). By integrating Objenious’ network access software on top of the STM32 ODE, developing connected devices is even easier. STM32 Nucleo LoRa kits are now certified and available to developers through ST sales channels.

STMicroelectronics | www.st.com

Logger Device Tracks Amp Hours (Part 2)

Lead ImageWachsmann

Alternative Energy Sources

In this follow on to Part 1 of his story, Bill describes putting to use the amp-hour logger that he built using a microcontroller and a clamp-on ammeter. This time he discusses modifying the amp-hour software so it can be used as an analog input logger to measure solar and wind power. A small solar cell and a homemade windmill are used..

By William Wachsmann

2017-11-012-Wachsmann-Fig1

FIGURE 1 Amp-hour log for the Office Circuit over 24 hours. It adds up to 14.728 A-hours and 1.767 kW-hours at 120 V.

In November and December 2016, I monitored all the circuits in my house. Some of the results were eye opening. We have a shed/workshop that is spray-foam insulated, where—among other things—we store paint cans. It’s heated by a 240-V baseboard heater and in the winter, we keep the temperature at around 10°C or about 50°F. The amp-hour logger showed that the heater was coming on about 3 times each hour and stayed on for 7 to 9 minutes each time. When it was on, it drew almost 7 A. The spreadsheet (file: SteelShed.xls) with the chart for these readings is included with the code—see Circuit Cellar article materials webpage for links.

Over a 24-hour period this amounted to an energy use of 12.5 kW-hours. At the rate we pay for electricity, it was costing around $3 per day or $90 dollars per month. Needless to say, we got rid of the old paint and turned the heater off. Now I only heat it if I need to work out there and it would otherwise be too cold. Figure 1 shows a chart of amp-hour usage in our office where my wife and I normally have three computers and two monitors running. Over a 24-hour period we use 1.767 kW-hours costing us about $0.50 per day. That’s not too bad but it’s actually more than the refrigerator at 1.357 kW-hours.

Table 1 (available in full article) shows the results from all the circuits in our house over a 24-hour period. (Not all on the same day!) I have since turned off the ‘Steel Shed Heater’ thus removing its 12.5297 kW-hours. The daily total is 31.39 kW-hours and monthly is 941.59 kW-hours. As a sanity check, that is quite close to our annual monthly average about 950 kW-hours. I have previously looked into going completely off grid, but it turns out to be too costly—mainly because the payback period would be 12 years or more. This also applies to “feed-in tariff” programs where solar or wind generated power is sent to the grid. The amount paid for this power is subsidized, and is higher than what we pay. But it requires an investment of $30,000 or more—for solar anyway—and wouldn’t be profitable for 8 to 10 years.

There is one exception to getting off grid cheaply. We have natural gas, which at current prices could be used to produce electricity at half the price we pay for power from the grid. The first problem here is that the type of small generators I would need are sold as backup systems and are just that. In other words, they are not designed to run continuously. If I tried to do that, I would void the warranty and the generator wouldn’t last anyway. There are larger ones designed to run continuously and are made to supply power in remote areas. They will run on either propane or natural gas, but are much larger than I need and much more expensive. Second, they are noisy and neither us nor our neighbors would be too happy. …

Read the full article in the November 328 issue of Circuit Cellar

Don’t miss out on upcoming issues of Circuit Cellar. Subscribe today!
Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.