Copperhill Books

Reprinted from “The Book Marketing Expert newsletter,” a free ezine offering book promotion and publicity tips and techniques. http://www.amarketingexpert.com

Comments were added by Wilfried Voss, author of A No-Nonsense Guide to a Professional Blog.

So you have a website, congratulations! Now let’s make sure it’s doing what it is supposed to be doing for you. Read: selling your book or product. While websites will differ in color, layout, and target audience, there are a few things that need to remain consistent. Let’s take a look at them.

1. Editing: Your website needs to be edited. There is no discussion on this topic at all. And don’t self-edit. Hire someone to go through your site page by page and make sure you don’t have any typos. Finding mistakes on your site is like finding typos on a resume. Doesn’t bode too well, does it?

My Comment: Don’t hire someone to check your web site. Use a spell-checker. Look for a spell-checking widget for WordPress. They are available.

2. Website Statistics: do you know your site stats? Did you even know you can get them? Site statistics are part of every website design. If you don’t have access to them make sure you get this. A good site stat service is Google Analytics, pretty comprehensive actually and easy to integrate into your site. You should know your traffic patterns and learn to read these reports (it’s a lot easier than it sounds). This way you’ll know what your site is doing and what it isn’t.

3. Media Room: even if you have never had any TV or radio appearances, you should have a media room. The media room is a great place to list all of your accomplishments as it relates to the book. Also, a good place to put your bio, picture (both of you and the book cover), as well as media Q&A, and a host of other items (I’ll cover the art and science of a good media room in an upcoming piece).

My Comment: Please be aware, while these tips are very valuable, they are targeted toward writers who are trying to promote their books.

4. Website Copy: Your website isn’t a magazine, people don’t read, they scan. Make sure your site isn’t so crammed with text that it’s not scannable. Ideally your home page should have no more than 200 to 250 words. Also, make sure you have a clear call to action. You want your visitors to do something on your site, yes? Make sure they know what that is, clearly and precisely.

5. Store: Yes, you should have a place for people to buy on your site, even if it means sending them off to Amazon.com or somewhere else to make their purchase. One key factor though: don’t make them hunt for it. Shorten the staircase. In other words, make it easy to find your stuff and then give them the quickest route to get there.

6. Design: I have two major rules in life: you should never cut your own hair or design your own website. Period. End of story. Why? Because much like editing our own books, we’re just too darned close to our message to be able to do it justice. Also, most of us are writers, not designers. Hire someone, invest the money, you’ll be glad you did. When you’re designing, also remember that your homepage should only do one thing. Your website can sell a lot of things, including any consulting or speaking services you offer, but your home page should be focused in on one major item. Surfers spend an average of 1/50th of a second on a website, if they have to stop and try and figure out what your site is about they will leave. I call it surf shock or analysis paralysis. Don’t make them guess what your site is about, or you will lose them.

My Comment: If you are using WordPress you don’t need a designer. That’s the beauty of WordPress. It’s a valid point, though, that you should concentrate on content once your blog is up and running.

7. Social content: make sure that you have something “social” on your site, whether it’s a blog, forum or even your very own social networking page. The easiest and best of these is a blog, in my opinion.

My Comment: WordPress allows comments on each page and post. When you write a post make sure – at the end of the entry – you invite readers to leave a comment.

8. Update often: search engines like sites that have a lot of fresh content, this will really help you with ranking in major search engines like Google. If you have a blog, you should plan to update it twice weekly at least.

9. Share and share alike: make sure that your content is easy to share. If you don’t have sharing widgets on your site (Upload to Facebook, Tweet This!, Digg, Delicious, etc.) then get your designer to add it to the site asap. Most blogging software comes with this all ready to go.

10. Placement and remarketing: first off, make sure that you understand how people surf, meaning where their eye goes to when they land on a website. The first place is the upper left hand quadrant of a site, that’s where your primary message should be. Then the eye goes to the center of your site. These two primary places are significant in conversion. You should have a clear message, and a clear call to action (whatever that action is). I also recommend funneling your visitors into a mailing list. You can do this via a sign-up on your home page and then an ethical bribe to encourage them to sign up. What’s an ethical bribe? It’s something you give them (of value) to get something – you might give them an ebook, a checklist or a special report. Just make sure it’s something your readers want.

Bonus tip: Understanding Anchor Text

If you ask any Search Engine Marketing Expert they will tell you the importance of anchor text. So what is this exactly? It’s the hyperlinked text that you click on to follow a link. Most people overlook this text, using words like “click here” or other nebulous terms. If used correctly, anchor text can really help with your site ranking. It’s not that difficult to implement really, you just need to understand a few basic concepts.

First, anchor text should be descriptive. It should describe the link you’re sending people to using keywords that reflect the page you’re recommending.

Second, if you know the high-traffic keywords for your market you can use those as well to describe the link (but only if the keywords relate to the page you’re sending visitors to).

Third, knowing where to use anchor text is almost as important as the text itself. All external links should be anchor text, but often web designers forget internal links (i.e. links leading to pages within your site) although they are equally as important. Your home page is also critical for anchor text links. If you have a blog (and you should) make sure that any article, website or blog you reference has anchor text in the hyperlink.

Creating these hyperlinks is easy, especially if you’re using them in a blog. Most blog software has some very simple one-click anchor text creation widgets.

So take some time and go through your site, make sure that anything you have hyperlinked is anchor text. Stay away from nebulous terms like “click here” or “follow this link” because you won’t get picked up by search engines that way. Make sure the text is focused and specific. How long can anchor text be? It doesn’t have to be long, but if need be, it can be multiple words. Keep in mind that as long as the words are relevant to your topic, the anchor text verbiage is all that matters.

My Comment: When you add a hyperlink under WordPress, it offers you to enter an Anchor Text (=Title) as shown below.

One of the ingenious features of CAN, the bit monitoring, contributes not only to the enormous reliability of Controller Area Network, but it is ironically also responsible for its biggest drawback, the limited physical distance of the CAN bus. Restricted physical distance is definitely an issue especially for applications such as elevators, security systems and other building technologies. The one and only way to extend the usable bus length without compromising the reliability is to lower the baud rate. In cases where reliability is not the main focus, e.g. diagnostics and low priority messaging, a CAN bus can be extended as far as the reach of the Internet.

Bus Length according to ISO-11898

The usable physical distance in a CAN network depends, first of all, on the applied baud rate as shown in the table below.

Baud Rate [kbits/sec] - Distance [m] – Distance [ft]
1000                                30                        150
500                                 100                      300
250                                 250                      750
125                                 500                      1500
62.5                               1000                    3000

While a distance of roughly 150 ft. at 1 Mbit/sec seems to be restrictive, especially for building technologies, a baud rate of 1 Mbit/sec can nevertheless be considered an overkill for such applications. Experience has shown that the vast majority of automation applications can work sufficiently with baud rates of 500 kbit/sec or even 250 kbit/sec and that includes demanding motion control applications.

In all consequence, CAN (including CANopen, a higher layer protocol on top of CAN) provides communication means between intelligent nodes. The keyword is “Distributed Intelligence”, which results in increased system performance. “Intelligence” means that the nodes are responsible for a major part of their control tasks. The more these nodes process internally, the less they depend on the communication means. The advantage of CAN lies primarily in its vast reliability.

Naturally, there are applications that require high speed and CAN provides that as well, however, with the drawback of limited physical distance.

CAN Repeaters

The bus length extension per CAN repeaters is a myth that is unfortunately being maintained by some manufacturers and vendors of these devices. CAN repeaters provide primarily electrical isolation and signal conditioning.

While CAN can be operated with a simple twisted pair of wires, the quality of the CAN bus cable can be a major factor in terms of maximum bus length. Poor cable quality will quickly knock a signal strength down below a receiver’s threshold. The result will be signal errors and consequently increased bus traffic due to error frames and repeated messages.

CAN repeaters can be used to boost the signal strength and maintain standard bus lengths, but not extend them. The only extension is the one from a poor quality network to a properly functioning network. Ironically, CAN repeaters, due to their internal delay times in the range of milliseconds, will actually shorten the usable bus length in the range of several meters.

CAN-to-CAN Gateways

Some vendors in the CAN business offer a variety of interfaces that support the communication between two separate CAN networks (e.g. the CAN-CBM-Bridge by esd electronics). Such devices allow to extend a CAN network by a factor of two, but they, too, have latency times due to reception, processing and re-transmission of CAN frames. Another disadvantage is that, for instance, both CAN networks cannot exchange error frames.

Such gateways, however, also post some advantages such as message filtering – to lower the bus traffic between the networks – and the use of different baud rates in the networks.

Ethernet Gateways

The ultimate way to extend the reach of a CAN application is the use of Ethernet gateways, which consequently even allow the connection to the Internet.

For instance, the EtherCAN device by esd electronics provides operation modes to either connect two separate CAN networks per Ethernet or allow the monitoring of network activities through the Internet.

In the first mode, you can connect two separate CAN networks per Ethernet to maintain almost unlimited physical distances. Each network will need its own gateway, which in turn will contribute to higher latency times. The EtherCAN also supports message filtering and thus can decrease the number of messages between the networks.

The second mode, operation through the Internet, is supported by the EtherCAN’s internal web server. Imagine, having your application run in Australia, but monitoring and analyzing the bus traffic in your office in Chicago. The EtherCAN comes with an extensive PC software package with CAN analyzing and monitoring features.

Summary

An extension of your CAN network is definitely possible, but it is important that you are aware of the drawbacks. The knowledge of the drawbacks, may they be minor or major, is the first important step to select the right solution.

Per definition, SAE J1939 provides serial data communications between microprocessor systems (also called Electronic Control Units – ECU) in any kind of heavy duty vehicles. The messages exchanged between these units can be data such as vehicle road speed, torque control message from the transmission to the engine, oil temperature, and many more.

SAE J1939 and its companion documents have quickly become the accepted industry standard of choice for off-highway machines. It was all too natural that organizations and manufacturers in the agricultural, military and marine industries, rather than re-inventing the wheel, adopted the proven combination of physical layer, Controller Area Network (CAN), and J1939 as the higher layer protocol for vehicles. However, it is in the specific nature of agricultural and military as well as marine applications that slight modifications, including a name change, were necessary.

These “new” protocols are:

• ISO 11783 (a.k.a. ISOBUS) – Agricultural Industry
• MilCAN – Military Applications
• NMEA 2000 – Marine Applications

ISO 11783 (ISOBUS)

ISO 11783, a.k.a. ISOBUS, is a CAN (Controller Area Network) Higher Layer Protocol based on the SAE J1939 standard for forestry and agricultural vehicles. ISO 11783 was a joint development by manufacturers in the agricultural and forestry industry to address the increasing needs for electronic control in the machinery/vehicles they produce.

ISO 11783 consists of the following parts, under the general title Tractors and machinery for agriculture and forestry – Serial control and communications data network:

• Part 1: General standard for mobile data communication
• Part 2: Physical layer
• Part 3: Data link layer
• Part 4: Network layer
• Part 5: Network management
• Part 6: Virtual terminal
• Part 7: Implement messages applications layer
• Part 8: Power train messages
• Part 9: Tractor ECU
• Part 10: Task controller and management information system data interchange
• Part 11: Mobile data element dictionary
• Part 12: Diagnostic
• Part 13: File Server

The ISO 11783 standards can be purchased through the International Organization for Standardization, ISO. Note: The price tags for each document are extraordinary.

The standard is managed by the ISOBUS group in VDMA (http://www.isobus.net). Note: The web site lacks the substance to be taken seriously. The bulk of the little information that exists is based on marketing material and most documents are in German. Technical information is virtually non-existent.

MilCAN

According to the official web site (http://www.milcan.org) : “MilCAN has been defined by a group of interested companies and government bodies associated with the specification, manufacture and test of military vehicles. The MilCAN working group was formed in 1999 as a sub-group of the International High Speed Data Bus – Users Group (IHSDB-UG) when a need was recognised to standardise the implementation of CANbus within the military vehicles community. The mission statement of this newly formed group was ‘To develop, for various application classes in all military vehicles, a common interface implementation specification based on CANbus’.”

Describing the MilCAN standard is not an easy task and the only reason it found its way onto this web site is due to the fact that it is partly based on J1939. It seems that the creators of the protocol tried to satisfy the protective demands of every European member (in this case especially the Germans and Brits) on one side and American companies on the other. One can only appreciate that the circle of members was not extended any further. MilCAN is an inconsistent mixture of CUP, a protocol developed by the German Army (Bundeswehr), SAE J1939, representing the American side, and CANopen, representing the European side.

As a resullt, there are two variants of MilCAN, MilCAN A and MilCAN B. MilCAN A is based on the 29-bit CAN identifier according to SAE J1939, the major difference being that MilCAN A supports deterministic data transfer and accommodates both, synchronous and asynchronous,  data. MilCAN B, on the other hand, is based on the 11-bit CAN identifier and can, at least officially, make use of devices that have been designed for CANopen. Also officially, it should be possible to mix J1939 devices with MilCAN devices on the same bus.

NMEA 2000

Of all the SAE J1939 derivatives, NMEA 2000 seems to be the only consequent and straight-forward adaptation of J1939.  While taking advantage of a proven and ingeniously designed protocol, NMEA 2000 defines only its own messages.

NMEA 2000 is used for marine data networks providing communication between marine specific electronic devices such as depth finders, chartplotters, navigation instruments, engines, tank level sensors, and GPS receivers.

It has been defined and is controlled by the US based National Marine Electronics Association (NMEA). Information on their official web site (http://www.nmea.org) is somewhat sparse. Another web site, http://www.jackrabbitmarine.com, however, provides in-depth information.

NMEA 2000 is a modernized version and replacement of an older standard, NMEA 0183. It has a significantly higher data rate (250k bits/second vs. 4.8k bits/second for NMEA 0183). It also uses a binary message format as opposed to the ASCII serial communications protocol used by NMEA 0183. Another distinction between the two protocols is that NMEA 2000 is a multiple-talker, multiple-listener data network whereas NMEA 0183 is a single-talker, multiple-listener serial communications protocol.

J1939 is a higher-layer protocol based on Controller Area Network (CAN). It provides serial data communications between microprocessor systems (also called Electronic Control Units – ECU) in any kind of heavy duty vehicles.

The main advantages of using CAN as a field-bus technology are reduced wiring (CAN requires only two wires between nodes), extremely reliable communication, easy implementation and improved maintenance and service capabilities, which consequently not only produce better vehicle performance, but also help to reduce production costs.

• J1939-based protocols are used in:
• Diesel power-train applications
• In-Vehicle networks for trucks and buses
• Agriculture and forestry machinery (ISO 11783)
• Truck-Trailer connections
• Military vehicles (MiLCAN)
• Fleet management systems
• Recreational vehicles
• Marine navigation systems (NMEA2000)

The protocol features of J1939 are based on two older SAE (Society of Automotive Engineers) specifications:

1. SAE J1708
SAE J1708 specifies on the physical layer of the communication link. It uses RS485 as an electrical layer operating at 9600 baud. (Note: Unlike RS232/485 there are no message collisions under CAN). Messages under J1708 start with a Message Identification Character, followed by the data information and a checksum. The message length is 21 characters (or less) and each data character is 10 bits long. Each character starts with a start bit of low polarity.

2. SAE J1587
SAE J1587 is a joint SAE/TMS “Recommended Practices for Electronic Data Exchange Between Microcomputer Systems in Heavy-Duty Vehicle Applications”. It regulates the communication and standardized data exchange between ECUs based on J1708 networks.

Note: The situation regarding documents/literature on J1708 and J1587 is as dire as with J1939.

The J1939 specification is described by a number of SAE documents, the SAE J1939 Standards Collection:

J1939
Recommended Practice for a Serial Control and Communications Vehicle Network*

J1939-01
Recommended Practice for Control And Communications Network for On-Highway Equipment

J1939-02
Agricultural and Forestry Off-Road Machinery Control and Communication Network**

J1939-11
Physical Layer – 250k bits/s, Twisted Shielded Pair

J1939-13
Off-Board Diagnostics Connector

J1939-15
Reduced Physical Layer, 250k bits/sec, Un-Shielded Twisted Pair (UTP)

J1939-21
Data Link Layer

J1939-31
Network Layer

J1939-71
Vehicle Application Layer

J1939-73
Application Layer – Diagnostics

J1939-74
Application – Configurable Messaging

J1939-75
Application Layer – Generator Sets and Industrial

J1939-81
Network Management

The motor data needed to select a motor are rated speed, rated torque, intermittent torque, and rotor inertia. However, the best servo motor selection criteria is to use the motor’s performance curve (torque over speed) and to verify it with the application requirements. Not all motor data sheets do provide such detailed information, since some manufacturers prefer to define the rated/intermittent torque and the rated speed of their motors in a more conservatively manner. Under certain conditions it is, however, possible to operate motors beyond their rated data.

Again, the following motor data are essential for the selection process:

• Rated Speed
• Rated Torque
• Max. (Peak) Torque
• Rotor Inertia

The following criteria have to be fulfilled:

• The motor’s rated speed is equal to or higher than the calculated (required) speed.
• The motor’s rated torque is equal to or higher than the calculated (System) RMS torque.
• The motor’s maximum torque is higher than the calculated (System) peak torque.
• The ratio of load to motor inertia does not exceed the user-defined safety factor.

In case of servo motors the ratio of load to motor inertia should not exceed 10:1. Otherwise the motor could start jerking.

Matters become a bit more complex when the motor’s performance profile, i.e. torque over speed performance, is used to determine whether or not the requirements are met.

To start with the basics, we need to see how the rated speed and rated/intermittent( (peak) torque of a motor is being defined. Basically it is at each manufacturer’s discretion how exactly they define the data. The following picture shows a sample of a motor performance profile:

In this example the rated speed (Vn) is defined as the max. possible speed where the motor still supports the continuous torque (Tcont). The max. speed of the motor is actually higher, but the torque will eventually go down to zero. The intermittent torque (Tmax) may be supported even at higher velocity than the rated speed, however, manufacturers tend to provide data that are on the safe side of the motor operation.

The previous profile may also be a simplified derivation from the actual motor performance. The following picture shows a more complex case:

One way to define the motor data would be to set rated speed, rated torque and intermittent (peak) torque at a safe point in the performance profile as shown in the next picture:

The red lines indicate an example to set the “official” motor data. Besides the point that this is a very coarse definition of the motor’s capabilities, this example also shows that the motor would be rejected, since it would (theoretically) not provide the required peak torque.

The following example shows yet another case where the rated motor data would not meet the application requirements, however, the performance profile does support the requirements.

The rated speed of this sample motor has been defined at 2000 rpm, but the torque requirements are low enough that the motor can support the torque even higher than at 2000 rpm.

The motion control engineer must take all of these described circumstances into consideration:

1. If the motor data sheet does not provide the performance profile (torque over speed or vice versa) of a particular motor, the engineer must use the rated data and make sure the following criteria are met:

• The motor’s rated speed is equal to or higher than the calculated (required) speed.
• The motor’s rated torque is equal to or higher than the calculated (System) RMS torque.
• The motor’s maximum torque is higher than the calculated (System) peak torque.
• The ratio of load to motor inertia does not exceed the user-defined safety factor.

2. If the motor data sheet does provide the performance profile (torque over speed or vice versa) of a particular motor, the engineer should still use the rated motor data. The actual selection, however, is based on a comparison of the performance profile with the application requirements, i.e. the engineer verifies whether or not the performance profile supports each torque at the corresponding speed as defined in the duty cycle.

Excerpt from: A Comprehensible Guide To Servo Motor Sizing by Wilfred Voss
Published by Copperhill Media Corpoation

1.    Overview

The vast majority of automated manufacturing systems involve the use of sophisticated motion control systems that, besides mechanical components, incorporate electrical components such as servo motors, amplifiers and controllers.

The straightforward task for the motion system design engineer is to specify the smallest motor and drive  combination that can provide the torque, speed and acceleration as required by the mechanical set up. However, all too often engineers are familiar with the electrical details, but do lack the knowledge how to calculate the torque requirements of the driven mechanical components. This will lead in many cases to improperly sized motion control applications. The impact, economically as well as technically, will be one of the topics in the following chapters.

Modern motor sizing software packages, such as VisualSizer-Professional, provide the convenience of computing all necessary equations and selecting the optimum motor/drive combination within minutes; they are, however, mainly used to circumvent the timely process of selecting a motor manually. While motor sizing programs can have an educational value to some degree, most of them do not provide any reference on how the equations were derived.

Some basic knowledge of inertia and torque calculations can have a profound impact on the motion system performance. Simple details, like when to use a gearbox in a motion system, may not only help to reduce costs, but will most certainly improve the system performance.

2.    The Importance of Servo Motor Sizing

The importance of servo motor sizing should not be underestimated. Proper motor sizing will not only result in significant cost savings by saving energy, reducing purchasing and operating costs, reducing downtime, etc.; it also helps the engineer to design better motion control systems.

2.1    Why Motor Sizing?

The servo motor represents the most influential cost factor in the motion control system design, not only during the purchasing process, but especially during operation. A high-torque motor will require a stronger and thus more expensive amplifier than smaller motors. The combination of higher torque motor plus amplifier results not only in higher initial expenses, but will also lead to higher operational costs, in particular increased energy consumption. It is estimated, that the purchase price represents only about 2% of the total life cycle cost; about 96% is electricity.

Proper servo motor sizing will not only assure best system performance; it also provides considerable cost savings.

The conventional method of servo motor sizing is based on calculations of the system load, which determines the required size of a motor. Standard praxis demands to add a safety factor to the torque requirements in order to cover for additional friction forces that might occur due to the aging of mechanical components. However, the determination of the system load and the selection of the right servo motor can be extremely time consuming. Each motor has its individual rotor inertia, which contributes to the system load torque, since Torque equals Inertia times Acceleration. The calculation of the system torque must be repeated for each motor that is being considered for the application.

As a result, it is not an easy task to select the optimum motor for the application considering the vast amount of available servo motors in the marketplace. Many motors, that are currently in action, have been chosen mostly due to the fact that they are larger than required and were available short-term (e.g. from inventory). The U.S. Department of Energy estimates that about 80% of all motors in the United States are oversized.

The main reasons to oversize a motor are:

• Uncertain load requirements
• Allowance for load increase (e.g. due to aging mechanical components)
• Availability (e.g. inventory)

Not only is the power consumption higher than it should be; there are also some serious technical considerations.

2.2    Technical Aspects

Oversizing a motor is naturally more common than undersizing. An undersized motor will consequently not be able to move the load adequately (or not at all) and, in extreme cases, may overheat and burn out, especially when it cant dissipate waste heat fast enough. Larger motors will stay cool, but if they are too large they will waste energy during inefficient operation. After all, the motor sizing process can also be seen as an energy balancing act.

AC motors tend to run hot when they are loaded too heavily or too lightly. Servo motors, either undersized or oversized, will inevitably start to vibrate or encounter stalling problems.

One of the major misconceptions during the motion design process is that selecting a larger motor than required is only a small price to pay for the capability to handle the required load, especially since the load may increase during the lifetime of the application due to increased mechanical wear. However, as demonstrated in the picture below, the motor efficiency deteriorates quickly when the motor operates below the designed load.

Picture 2.2.1: Example Efficiency vs. Load

Picture 2.2.1 shows an example of two motors, 10 HP and 100 HP. In both cases there is a sharp decline of the motors efficiency at around 30% of the rated load.

However, the curves as shown in the picture, will vary substantially from motor to motor and it is difficult to say when exactly a motor is oversized. As a general rule of thumb, when a motor operates at 40% or less of its rated load, it is a good candidate for downsizing, especially in cases where the load does not vary very much. Servo motor applications usually require short-term operation at higher loads, especially during acceleration and deceleration, which makes it necessary to look at the average (RMS) torque and the peak torque of an application.

There are, however, advantages to oversizing:

• Mechanical components (e.g. couplings, ball bearings, etc.) may, depending on the environment and quality of service, encounter wear and as a result may produce higher friction forces. Friction forces contribute to the constant torque of a mechanical set up.
• Oversizing may provide additional capacity for future expansions and may eliminate the need to replace the motor.
• Oversized motors can accommodate unanticipated high loads.
• Oversized motors are more likely to start and operate in undervoltage conditions.

In general, a modest oversizing of up to 20% is absolutely acceptable.

High efficiency motors, compared to standard motors, will maintain their efficiency level over a broader range of loads (see picture 2.2.2) and are more suitable for oversizing.

Picture 2.2.2: Example High/Low Efficiency Motors

2.3    The Objective of Motor Sizing

The main objective of motor sizing is based on the good old American sense for business: Get the best performance for the lowest price. As we have learned from a previous chapter the price contains the following components:

Purchasing Costs 2%
Repair, Service, Maintenance, etc. 2%
Operating Costs (Electricity) 96%

In order to get the best performance for the best price it is mandatory to find the smallest motor that fulfills the requirements, i.e. the motor that matches the required torque as close as possible. The basic assumption (which is true for the majority of cases) is that small torque is in direct proportion to smaller size, lower costs and lower power consumption. Smaller power consumptions also result in smaller drive/amplifier size and price.

From a technical standpoint it is also desirable to find a motor whose rotor inertia matches the inertia of the mechanical setup as close as possible, i.e. the optimum ratio between load to rotor inertia of 1 : 1. The inertia match will provide the best performance. However, for servo motors a ratio of up to 6 : 1 still provides a reasonable performance. Any higher ratios will result in instabilities of the system and will eventually lead to total malfunction.

In many cases it makes sense to add a gear between motor and the actual load. A gear lowers the inertia that is reflected to the motor in direct proportion of the transmission ratio. This scenario allows to run smaller motors, however, with the price of the gear added to the system. On the other hand the price reduction by using a smaller motor/drive combination may more than just compensate for the gears price.

In review the objective of motor sizing is to:

• Get the best performance for the best price
• Match the motors torque with the load torque as close as possible
• Match the motors inertia with the load inertia as close as possible
• Find a motor that matches or exceeds the required speed

3.    The Motor Sizing and Selection Process

The motor sizing and selection process is based on the calculation of torque and inertia imposed by the mechanical set up plus the speed and acceleration required by the application. The selected motor must be able to safely drive the mechanical set up by providing sufficient torque and velocity.

Once the requirements have been established, it is easy to look either at the torque vs. speed curves or motor specs and choose the right motor.

The sizing process involves the following steps:

1. Establishment of motion objectives

A written outlining of the motion control application will help to establish the necessary parameters needed for the next steps.

• Required positioning accuracy ?
• Required position repeatability ?
• Required velocity accuracy ?
• Linear or rotary application ?
• If linear application: Horizontal or vertical application?
• Thermal considerations Ambient temperature ?
• What motor technologies are best suited for the application ?

2. Selection of mechanical components

The engineer must decide which mechanical components are required for the application. For instance, a linear application may require a leadscrew or a conveyor. For speed transmission a gear or a belt drive may be used.

• Direct Drive ?
• Special application or standard mechanical devices ?
• If linear application: Use of linear motor or leadscrew, conveyor, etc. ?
• Reducer required Gearbox, belt drive, etc. ?
• Check shaft dimensions select couplings
• Check mechanical components for speed and acceleration limitations

3. Definition of a load (duty) cycle

The engineer must define the maximum velocity, maximum acceleration, duty cycle time, acceleration and deceleration ramps, dwell time, etc., specific to the application.

• Define critical move parameters such as velocity, acceleration rate
• Triangular, trapezoidal or other motion profile ?
• If linear application: Make sure the duty cycle does not exceed the travel range of linear motion device.
• Jerk Limitation required ?
• Consideration of thrust load ?
• Does the load change during the duty cycle ?
• Holding brake applied during zero velocity ?

4. Load calculation

The load is defined by the torque that is required to drive the mechanical set up. The amount of torque is determined by the inertia reflected from the mechanical set up to the motor and the acceleration at the motor shaft.

• Calculate inertia of all moving components
• Determine inertia reflected to motor
• Determine velocity, acceleration at motor shaft
• Calculate acceleration torque at motor shaft
• Determine non-inertial forces such as gravity, friction, pre-load forces, etc.
• Calculate constant torque at motor shaft
• Calculate total acceleration and RMS (continuous over duty cycle) torque at motor shaft

5. Motor Selection

The motor must be able to provide the torque required by the mechanical set up plus the torque inflicted by its own rotor. Each motor has its specific rotor inertia, which contributes to the torque of the entire motion system. When selecting a motor the engineer needs to recalculate the load torque for each individual motor.

• Decide the motor technology to use (DC brush, DC brushless, stepper, etc.)
• Select a motor/drive combination
• Does motor support the required maximum velocity ? If no, select next motor/drive.
• Use rotor inertia to calculate system (motor plus mechanical components) acceleration (peak) and RMS torque
• Does motors rated torque support the systems RMS torque? If no, select next motor/drive.
• Does motors intermittent torque support the systems peak torque? If no, select next motor/drive.
• Does the motors performance curve (torque over speed) support the torque and speed requirements? If no, select next motor/drive.
• If the ratio of load over rotor inertia exceeds a certain range (for servo motors 6:1) consider the use of a gearbox or increase the transmission ratio of the existing gearbox. Servo motors should not be operated over a ratio of 10:1.

The following flow chart demonstrates the motor sizing and selection process:

Excerpt from: A Comprehensible Guide To Servo Motor Sizing by Wilfried Voss
Published by Copperhill Media Corpoation

by Wilfried F. Voss – http://www.frogenyzurt.com

Sub-Titled:
How your neighbors are making a big second income by writing and publishing their own money-making websites.

Usually, I try to be nice and diplomatic about books that I didn’t care for. After all, it’s all about personal taste. However, when I smell fraud I get aggravated, and I have a hard time holding back some profane thoughts. That is the case with New Path to Riches by Nick Usborne.

As a matter of principle, I do not buy any books that promise the reader the guaranteed path to success, but every now and then I need a slap in the face, I guess. The not-so-literal slap in the face came with buying and reading New Path to Riches by Nick Usborne.

Well, my excuse is that I bought the eBook version through BookLocker.com, a business managed by Angelo Hoy (who also publishes WritersWeekly.com). I do LOVE Angela’s weekly newsletter, and I do love her style and her approach to publishing. She is, however, not responsible for the content of the books she sells. My hope was that the authors she deals with are as honest and as straight-forward as Angela, or, at least, in the same ballpark. Unfortunately, Nick Usborne is not in the same class as Angela.

My hope was also to learn intimate details about creating a money-making web site, but his book New Path to Riches is a 150+ page collection of mindless blabbering that reads like the presentation of a motivational speaker. There is absolutely NOTHING in this book that you cannot find on the Internet free-of-charge. There is close to NULL profound information on how to create a web site and make it work – as I said before, just mind-boggling bla, bla, bla, and… bla.

Don’t waste your money with this book. Spend a few minutes on the Internet to get REAL information.

Last, but not least, if you want honest information on how to start a web site or blog and make money from it, check out my book, A No-Nonsense Guide to a Professional Blog (There is also a preview of the book). Honestly, I wrote it after learning about the so-called “Google Profit Library”, but especially after reading New Path to Riches by Nick Usborne. I deemed it was time to stop the nonsense. The book shows you step by step how to set up a professional blog with some advice on how to run it, and maybe even make some money from it. The difference is, you don’t pay me at all (I would appreciate that you buy the book, paperback or PDF), and the required investment of roughly $120…200 per year goes to your Internet service provider for running your web site. Also, check out myprofessionalblog.com. This is the web site I created to write the book, meaning I created the web site, made screen-shots and included them into the document.

by Wilfried F. Voss – http://www.frogenyozurt.com

Product Description

Few outside the security services have heard of 14 Company. As deadly as the SAS yet more secret, the Operators of 14 Company are Britain’s most effective weapon against international terrorism. For every bomb that goes off 14 Company prevent twelve. The selection process is the most physically, intellectually and emotionally demanding anywhere in the world. Trained to operate under cover, Operators have at their disposal an arsenal of techniques and weapons unmatched by any other UK government or military agency. This is the true story of one Operator and of some of the most hair-raising military operations ever conducted on the streets of Britain.

Review

My reason to buy this book was the hope that it would contribute interesting insights for my research on the Irish Troubles. To put it in a nut-shell: I hope the author didn’t quit his day job over writing this book. What caught my attention was the sub-title “On the streets with Britain’s most secret service,” which proves yet again how important, but also how terribly misleading a title can be.

Little did I know how immature the writer deals with a serious topic like the Irish Troubles. The book starts with “Standby, standby. Zero, Oscar. I have Bravo 1 foxtrot from Alpha 2 towards Charlie 2,” and it doesn’t get much better from there. There is not much to say other than reading this book was a huge waste of my time.

by Wilfried F. Voss – http://www.frogenyozurt.com

Product Description

A research fellow in history at De Montfort University Leicester (U.K.), Cronin offers synopsis with little insight in this overview of Irish history. Starting with ancient Gaelic Ireland, he quickly moves on to the introduction of Christianity, the Viking and Norman-Anglo invasions, and the effects on the Protestant Reformation. With Cromwell’s invasion in the mid-17th century came the redistribution of land from the Catholics to the Protestants. This is the strong point of the book, as Cronin compacts convoluted Irish history into a comprehensive, readable form. He then briefly covers the 1798 Rebellion, Catholic emancipation under Daniel O’Connell and the great famine of the 1840s, all of which set the stage for the Fenian rebellion of 1867. The Fenians, though unsuccessful, would leave their imprint on Parnell and his Land League. Cronin paints a concise, albeit limited, picture of the events of 1914 through 1923. His portrait of John Redmond, the head of the Irish delegation at Westminster, is telling of the man and his political philosophy. Redmond, who warmly embraced Britain’s entrance into WWI, found himself isolated from his own constituents in the aftermath of the 1916 Rebellion. But the author’s sketchy and incomplete analysis of post-Civil War Ireland and some of his questionable judgments of important figures will leave some readers baffled. He praises the government of William T. Cosgrave (1922-1932) for his post-revolution adaptation of the in-place British systems in many respects returning Ireland to the status quo ante. He also praises Eamon DeValera, whose ascension to power is often viewed as hypocritical, because he renounced everything for which he had fought the Civil War. Cronin’s assessment of the Good Friday Agreement is inadequate: only once does he mention President Clinton, who played the seminal role in brokering the accord. Unfortunately, Cronin sacrifices depth for the sake of brevity; his superficial rendering would best serve as a primer for those who are new to Irish history.

Review

I have to say, I do not agree with the above product description (Amazon.com). The author did a great job of condensing the events of the tumultuous Irish history into less than 300 pages. Any complaint that one particular detail had not been explained to the full extend is simply ridiculous. This book is for everyone looking for a concise, yet very readable description of Irish history. During my intense research for my novel The Bleeding Hills I have been reading extensively, and one of the very few books I can whole-hertedly recommend is A History Of Ireland by Mike Cronin. Reading this book is highly recommended! I like that it is, compared to many other works on Ireland, actually readable and entertaining. If you need a relatively quick overview on the history of Ireland (the tile of the book doesn’t lie!) this is the one I recommend.

Sigerson Clifford was an Irish poet and playwright. I took a line from his poem The Boys of Barr Na Sraide, the line that goes “And when the hills were bleeding and rifles were aflame…”, to use it as the title for my book The Bleeding Hills. The research for my also revealed that there is not a lot of information available that would describe the person Sigerson Clifford in more detail, and that is the reason I created a web site in the hope that people all over the world find it and possibly add more data.

Sigerson Clifford (1913 – 1985)

Clifford was born at #11 Dean St, Cork City, and was christened Edward Bernard Clifford. His parents, Michael Clifford and Mary Anne Sigerson, were from County Kerry, and they returned there in the following year, to Cahersiveen, where he was raised on the Ring of Kerry. He attended the Christian Brothers school in that town.

At the age of six, he went to live with his paternal grandfather, Ned Clifford, on the Old Road in the town. Ned was a gifted storyteller, and his influence encouraged Eddie to write poems and stories while at school. As a writer, he adopted the first name Sigerson in honour of his maternal family, although he continued to be known as “Eddie” to family and friends. At nineteen, after finishing secondary school, he joined the Civil Service, and worked for several years in unemployment exchanges in Cork and Kerry. In 1943 he moved to Dublin.

In 1945 he married Marie Eady from Cork. Clifford continued to write, but he did not leave work, and retired from the Civil Service in 1973.

Sigerson Clifford died in Glenageary, County Dublin on 1 January 1985, aged 71, and was interred in Kilnavarnogue Cemetery in his native Cahersiveen, with a graveside oration by his fellow Kerry author and playwright, John B Keane. A monument in memory of Sigerson Clifford is located in Cahersiveen.

Clifford wrote a number of poems and plays, including The Great Pacificator, which was staged at the Abbey Theatre, Dublin, in 1947. Clifford is best remembered for his poem, The Boys of Barr na Sráide, which was named after a street in Cahersiveen. The poem recalls the life of his boyhood friends starting from when they were young children through to the Black and Tan period, and up to the civil war. The poem speaks of the Irish tradition of “hunting for the wran” (wren), a small bird, on St. Stephen’s Day, 26 December. Later set to music, the song has been recorded by numerous traditional and folk singers including Christy Moore and Tim Dennehy.

Contribute to the Sigerson Clifford web site

If you can contribute any information on the life and work of Sigerson Clifford please have a look at the web site I created to honor his life and work. Unfortunately, there is not a great deal of information on Sigerson Clifford, and I would love to show photos and a more detailed biography.

The web site is located at SigersonClifford.com.

There has been a great deal of commotion about Google’s controversial and potentially anti-competitive plans to digitalize millions of books, or the pricing war going on between Walmart, Target, and Amazon. It is surprising that only little attention has been paid to an even greater threat to authors and publishers by Scribd.com, a web site allowing the distribution of copyrighted documents, including digitalized versions of popular works such as J.K. Rowling’s Harry Potter and the Chamber of Secrets, and The Tales of Beedle the Bard.

J.K. Rowling used the power of her legal team to have her works removed, but her focus was the protection of her intellectual property, not the financial damage. While big publishing houses or successful authors like J.K. Rowling can easily dismiss the financial loss, the situation becomes quickly explosive for small publishing businesses. For instance, BookLocker.com noticed more than 13,000 scribd.com users had “read” their best selling book, Cancer-Free, before the author was able to have his copyrighted material removed. Two of my books were listed for roughly six months – without my knowledge – and the loss of sales is roughly $20,000, with no chance to tackle a heavyweight like Scribd.

Scribd.com is not the only document-sharing web site, but with more than 50 million users and more than 50,000 document uploads per day, it appears they aim to be the YouTube for print. Scribd.com can most certainly be helpful for authors, publishers, and bookstores. They can upload their documents in their entirety and sell them for a good profit, or they can upload only an excerpt to wet the appetite of potential readers. The content on Scribd.com ranges from a majority of dull documents to a number of copyrighted books, fiction and non-fiction alike.

There are two sides to the problem: First, Scribd.com provides the means to upload copyrighted material without “editorial interference or approval”, thus creating financial damage to the publishing industry. Add to this that the majority of authors and publishers are still unaware of the issue.

Secondly, there are a number of publishing businesses – sleeping with the enemy – who believe in a strange marketing policy of allowing the free-of-charge viewing, reading, printing, and downloading of their published books for “a limited time”.

The absence of “editorial intervention and approval” in combination with a highly flawed sign-up process, however, encourages the crime. Scribd.com makes it very easy to sign up with a fake e-mail address. For instance, a user can sign up as johnmccain@thewhitehouse.com and then upload the latest Dan Brown, provided it exists in an electronic format. Scribd.com does not actively verify the users’ authority, and, in case of an illegal upload, they are usually unable to identify the perpetrator. Of course, they pop up a dialog window asking to confirm the rights to the document in question. But, seriously, criminal minds don’t care, and there are a great number of users who may be unaware of the consequence of their actions.

Removing copyrighted documents from the Scribd.com web site is easy, though – they promote this heavily as one of their “helpful features”. Scribd.com provides an e-mail template and the author or publisher fills in the appropriate information. It usually takes only a few days to process the request, but it also means that the document is still available for view, print, or download until the verification process is completed.

And even then, Scridb is still holding on to the document, meaning it is still stored in their database, which posts yet another legal problem because they store copyrighted documents without explicit authorization by the document’s owner. Officially, they use the existing copy to verify it against new uploads and thus prevent further copyright infringement.

I strongly suggest that each author and publisher check out the Scribd.com web site and search for names and titles. If your work is listed on Scribd.com, send an e-mail to copyright-at-scribd.com using the legal form they recommend. You will receive an automated response stating that your request has been received. They also encourage you to leave comments, and I dared doing just that, without being insulting. As a matter of fact, the person in charge at Scribd.com, their Customer Care Director, did not appreciate my feedback and closed the request immediately. I had to re-apply, and my book was finally removed from their web site.

The law firm of Camara & Sibley has decided to take on Scribd, seeking class action status against the site in a lawsuit filed in a Texas federal court. The charge: “Like YouTube, Veoh, and other user-generated content sites, Scribd makes it just too easy to upload copyrighted content without permission.”

Ironically, a copy of the lawsuit is available through the Scribd.com web site (Search for Scott v. Scribd Complaint).

For further information on Scribd.com, log on to my web site at http://www.frogenyozurt.com.

Wilfried F. Voss was born and raised in Germany, but for the past twenty years his home and his heart have been in beautiful New England. He shares his birthday with celebrities like THE KING (Elvis Presley) and David Bowie, which is January 8 (not the same year, though). He has published three books on technical topics and is currently exploring another genre of writing, namely fiction writing. In Septmber of 2009 he published his first novel “The Bleeding Hills.”

Growing up as a teenager in the late 1960s and early 1970s, and loving contemporary pop music, I saw the release of a great number of songs that have not lost their popularity up to this day. One of these songs is Catch The Wind by Donovan Leitch.

Donovan (Donovan Phillips Leitch, born 10 May 1946, in Maryhill, Glasgow), is a Scottish singer-songwriter and guitarist. Emerging from the British folk scene, he developed an eclectic and distinctive style that blended folk, jazz, pop, psychedelia, and world music. Donovan came to fame in the United Kingdom in early 1965, and his popularity spread to the USA and other countries. He scored a string of hits in the UK, the USA, Australia and other countries, including several British and American #1 hits and million-selling records.

He became a friend of leading pop musicians including Joan Baez, Brian Jones, Bruce Springsteen, and The Beatles. He influenced both John Lennon and Paul McCartney when he taught them his finger-picking guitar style in 1968. Some of his most popular songs are Catch The Wind, Sunshine Superman, Colours, Universal Soldier, and many more.

His first hit song Catch The Wind was used just lately as background music for a car commercial, which is remarkable, because the original version they used in the commercial was from 1965. This original version is very basic, just Donovan, his guitar, and his harmonica. Later the producers added some strings. That is the reason why most Donovan compilations contain two versions of the same song.

There is, however, a forgotten third version, which was released a few years later. It is a more romantic version, and it is quite longer than the original. For many years I have been trying to get my hands on this version, but it seems it got lost in history. The only version I did find and which comes closest to the last release is on Donovan’s record Donovan: Best of Live. So, the search will continue.

The CD also contains a live version of Hurdy Gurdy Man, one of his more psychedelic songs, and this is where we come to Donovan, Four Beatles, One Beach Boy, and Mia Farrow. During the song Donovan explains how George Harrison suggested a verse for Hurdy Gurdy Man, but he never recorded it. His exact description, with his strong Scottish accent, is as follows:

“When I wrote this song I was in India with four Beatles, one Beach Boy, and Mia Farrow. We were gathered together one day in Maharishi’s bungalow, these four Beatles, one Beach Boy, and Mia Farrow. There was an embarrassed silence in the room. Maharishi, he sat cross-legged on the floor. And John Lennon, the wit and the humorist, he decided to break the silence. So, he walked up to Maharishi as he sat on the floor, and he patted him on the head and he said, ‘There’s a good guru!’ We all laughed! And Maharishi laughed the loudest. Later that night, as we were gathered together, on the roofs of our bungalows under the tropical Indian stars we brought out the guitars, and I started to write this song. And George Harrison, he turned to me, and he said, ‘I could write a verse for this song, Don.’ And he did. But I didn’t record it.”

And here is the long lost verse of George Harrison:

When the truth gets buried deep
Beneath a thousand years of sleep
Time demands a turnaround
And once again the truth is found

Hurdy Gurdy Man
by Donovan Leitch

Thrown like a star in my vast sleep
I open my eyes to take a peep
To find that I was by the sea
Gazing with tranquillity.

‘Twas then when the Hurdy Gurdy Man
Came singing songs of love,
Then when the Hurdy Gurdy Man
Came singing songs of love.

Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang.
Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang.
Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang.

Histories of ages past
Unenlightened shadows cast
Down through all eternity
The crying of humanity.

‘Tis then when the Hurdy Gurdy Man
Comes singing songs of love,
Then when the Hurdy Gurdy Man
Comes singing songs of love.

Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang.
Hurdy gurdy, hurdy gurdy, hurdy gurdy, hurdy gurdy, hurdy gurdy.
Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang.
Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang.

Here comes the roly poly man and he’s singing songs of love,
Roly poly, roly poly, roly poly, poly he sang.
Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang,
Hurdy gurdy, hurdy gurdy, hurdy gurdy, gurdy he sang