Be careful what you ask for


Thread Starter

Guy H. Looney


I would like to use the email posted by Jon Oak (shown below) as a basis for my comments to address the "open" topic that has been so heavily discussed (John, I'll give you my 2 cents on your
application in a separate email). I have been monitoring the conversations concerning the "need" for open systems very closely & it seems to have developed into 2 distinct topics. The first is the need for open architecture and the second is the need to be able to purchase equipment directly over the internet (or from the
manufacturer) at the best price possible.

Over the past several months, many of you have used the term "vendor" with much resentment. I can only assume from the comments & wise-cracks, that many of you view vendors as worthless entities that do nothing but mark up a piece of equipment & sell it for a profit. I work for a "vendor" that considers itself a "value added distributor". I'm sure many of you will get a good chuckle out of that term & will immediately think that the only value I add is someone to beat up when your equipment is late.

I would hope that my previous posts would prove that I have some degree of competence in the motion control industry. I have only been in this industry for 4 1/2 years. However, I have done nothing but motion control for that time. I have seen hundreds of applications & feel I have a tremendous amount of experience to share in terms of what works & what doesn't. Make no mistake about it, I do not claim to be a expert & eat my share of humble pie regularly.

Jon's email proves that providing "open architecture" does not make the system any simpler to use. He's going to use a PC, some operating system (Iet the debates begin over which one he should use), a motion control card, motors, amplifiers, and some sort of mechanics. Further he could use an SST card in the PC to
plug in anybody's I/O. How much more open can you get? Okay, now we've got a truly open system and everybody's happy right? Well who's going to tell him how to make it work? Let's assume he
uses the following:

Galil's DMC-1730 motion control card w/ an Active X toolkit to interface to Visual Basic
Motors from Custom Servo Motors
Amplifiers from Pac Sci
Mechanics from THK
Gearheads from Bayside

How many of you could make this system work? This is not a straw poll, so please don't respond with "I could". The last thing I want is 300 emails telling me how to make it work. I already know how to make it work. Now for those of you that feel comfortable with the first question, how many of those people could get it up and going in less than a week? Once again no response is necessary.

My point to all of this is, that the more open you make the automation world, the more finger pointing you are going to have if you choose to deal directly with the manufacturers. Let's face it, Allen Bradley, Parker, Siemens, etc. wants you to buy their entire system. If you choose to build a system from pieces there is
going to have to be someone to step up & assist you. Integrators do not have the time to become experts on everybody's equipment. But Guy, we don't have to do that.....we'll find one system that we like & standardize on it. If you're an OEM you can do that. If you're an integrator, there's a little thing called "customer spec'd
equipment" that makes that thought process an impossibility.

It seems to me that the desire for open systems strengthens the position that "vendors" (distributors) have. Let's say I sell a
$20,000 system to do what Jon is looking for. Assume that I have a 30% GPM built in to that price. That means that if he could buy direct, he would be able to save $6,000 on capital costs. That's a lot of money right? Well let's look at what that $6,000 gets him:

1) Engineering time to properly size the motors, drives, & gearheads (torque, speed, regen, inertia matching, etc.)
There are sizing software programs available to automate this task, but some are buggy & if you don't understand what is taken into account when sizing is performed you are at the mercy of the software to select the system for you. The software doesn't tell you everything that it assumes. When you give it a distance to move & a time to move it in, it probably assumes a trapezoidal move profile with a 1/3, 1/3, 1/3 time allocation for acceleration,
constant velocity, and deceleration. What it doesn't tell you is how to program the controller to achieve that move profile. If you program the wrong move profile the system may not work. Also,
what if your motor doesn't have enough speed for the move? Well you could increase the acceleration & deceleration rates to lower the top in speed requirements instead of buying a bigger motor. The opposite could be done to lower the torque & increase the top in speed. Further, many programs don't take regen into consideration or explain the importance of 2) Engineering time to make sure the system will work.
I can't tell you the number of times that I've seen gearheads break because the wrong one was chosen. People constantly try to save money by putting inferior gearheads on servos. A cheap gearhead can be used on steppers because they are either moving or not moving. Servos are always moving (even when they appear to be at rest, they are still servoing / moving). A
servo can destroy a gearhead designed for stepper systems by shaking it apart. If you're in a hot environment or moving constantly at a high rate of speed many gearheads will heat up & transfer the heat back to the motor which could damage or destroy the motor. Many gearheads have the ring gear pressed in. Further the ring gear could be made out of a different material than the housing. If that's the case, the two metals will have a different coefficient of expansion due to heat. This could lead to a lot of problems.
Orientation of the gearhead is also important. If the shaft is facing upward you will need to let the gearhead Will the motor even
mount to the mechanical system? Just because it will give enough torque and speed it doesn't mean it will physically mount. Do I need to clamp the torque of the servo to make sure I don't break
the mechanics? If so, does the control scheme (controller &/or amplifier) have that ability? Can the mechanics handle the forces & moments to give me the life I need? Do I have enough resolution in the system to ensure I can obtain the repeatability I need? Just because the mechanical system has a repeatability spec that
meets my requirements, it doesn't mean that I have enough commanded resolution to obtain that repeatability.

What about compatibility between the drives, motors, and controller? Does the inductance of the motor allow it to work w/ the amplifier? Does the switching frequency of the amplifier pose a problem to the motor? Does the controller have an encoder input great enough to handle the input frequency of the encoder? Is the motion controller's I/O compatible w/ the amplifier's I/O? In other words what if the fault output & enable input on both devices are PNP? That's gonna require extra relays to make the system work.

What about the deratings? Motor's have a torque speed curve that is based on the motor being attached to an aluminum heat sink w/ 10" x 10" x 1/4" dimensions. If you don't have that, you can burn the motor up at rated torque (I've seen it happen). Gearheads are derated based on the duty cycle and the gear ratio.

What about noise? I could write another book on that topic alone.

4) On-site support for hardware setup
We will usually spend at least 1 full day; many times 2 or 3 days to help a customer get up & going.
5) Phone support for programming issues
We have equipment in our office that allows us to simulate programs in the field. This allows us to debug or offer suggestions
to improve the existing program.
6) Wiring schematics to configure the entire system....enough said
7) Reduce finger pointing.
We are the ones that have to deal w/ the manufacturers pointing fingers at each other 95% of the time. I once spent 80 hours in 3 days trying to get a customer's motion controller work w/ the motors & drives I sold him. By the time it was over I knew more about the IMC-123 module than most of the AB guy's did (no, I don't sell AB products).
8) Spares on our shelf
Many manufacturers are cutting costs by becoming JIT manufacturers. This means that normally it will take anywhere from 2 days to 4 weeks to ship.

Is that worth $6,000? I wish I could believe that everyone would say yes. Unfortunately, there are too many people shopping around for the lowest price w/ no regard to the value add. If I had a nickel for every time that I designed a system for an engineer only to have a purchasing agent shop the parts around to find the lowest
price I could retire. I can't blame that purchasing agent because they get paid to save money. The problem I have is trying to justify
my value added resource.

Let's face it there are plenty of motion control products out there that could do 70% of all applications. How do you chose which one to use? Well if we continue down the path of motion being bought on-line, we're going to find out the hard way. Why do some manufacturers have a bad name at certain companies? Is it because they make a bad product or is it because the product was misapplied? I would say the answer is about 30/70 on that one.

Are all these organizations that are working to open up the industry really helping? ODVA has made tremendous strides to make DeviceNet a standard open field bus. That's all well and good, but all DeviceNet products are not the same. I have heard many complaints that just because it says it's DeviceNet, doesn't mean it
is. Multiple devices from multiple vendors all on the same field bus can cause multiple problems. I applaud ODVA's efforts & think
they've really helped. However, don't fool yourself into believing that there are no problems.

My point to all this isn't to prove how valuable companies like mine are. My point is to make sure that we reevaluate what we're asking for. Customers are asking for direct pricing & free support. Open architecture should not equate to openly buying these products over the internet. Quite the opposite actually; it will probably
require even more support from value added distributors because the tendency will be for manufacturers to point the finger at each other. This could change over time, but then again PC's were supposed to replace PLC's many years ago.....that's another story.


Guy H. Looney
Sales Engineer

Regan Controls, Inc.
475 Metroplex Dr.
Suite 212
Nashville, TN 37211
phone: (615) 333-1940, ext. 322
fax: (615) 333-1941
[email protected]

>>> List Management Account <[email protected]> 03/24/00 11:41AM >>>
------- Forwarded message follows -------
From: Jon Oak <[email protected]>
Subject: MOTION: Resolver vs Encoder and Servo Drive selection

I am working on a single axis and a dual axis servo machines that are related. I am going to use a PC bus based motion card (galil, MEI, etc.) and some pc based control software. I have the option of specifying encoder or resolver but am not sure what the benefits of each technology. Being that these machine will be going into an
automtive plant environment being robust both mechanically and electically are key. Cost is also a bit of an issue, but not as important as reliability.

Question 2: Same system as above. What should you look at in a servo drive? currently I am considering the following as the requirements

Digital Drive (no pot. tuning
High voltage bus (460v Drive)
20 amp continuous 40 amps peak (min)
Communications port to talk to PC

What else should be taking into account. I tend to think of these as somewhat of a commodity item espceailly since i am using a PC motion card). I have seen a large price range $3500-2100 and
would like to make sure the lower cost options will be perform well.

Curt Wuollet

Hmmm. kinda commercial :^)

You have some good points, but I really think we need both VAR's and direct. I'd go along with your main idea except that you almost always have to do the front end work to see if the VAR's proposal makes sense. I have seen some truly bad suggestions and it is handy to have someone else to blame, but too frequently, whatever it is that they are interested in selling gets proposed as the "best" solution. True, they will often negotiate if it doesn't work, but that is way too late in the process to have happy customers. The direct approach has problems too. There are a lot of people who would buy direct that could benefit from some sage advice. Often the people who think value add is a waste of money are the ones who need it and the ones who can validate the VAR's approch could be buying direct. In the end, I'd say do the work if you can and buy
direct, you'll gain the knowledge. Or if you think you're in over your head, find a good VAR by word of mouth. The idea is, that somebody's got to do due diligence. The really bad outcomes are brought on by thinking you can avoid both the cost and the work.


Curt Wuollet,
Wide Open Technologies......Consulting....I sell nothing but time.

D.C. Pittendrigh

Hi All

I call myself a systems integrator, I also happen to be a VAR (value added reseller) for Siemens (and a few others) I consider my addition of value to be advising my clients correctly, ensuring they do not buy the wrong stuff, and ensure they don't get ripped off if they don't want to buy from me(many won't buy from me as they feel more comfortable with the backing of a big group such as Siemens if the hardware doesn't work). I make my money out of software/systems integration, I am prepared to prostrate myself and be beaten up if the product I sell is late in delivery as well, but I do not sell any products which are second best. I believe this is the best service to offer my clients.

Having said that I have one for Guy, "Hear hear", I couldn't agree with you more, I only wish all my potential clients also had your (and my) vision.

Donald Pittendrigh
Another thing to consider is that the folks making the comments on this forum are in many cases technically literate. Kind of like preaching to the choir . . . .

I think that the main concern voiced about associating complex motion integration with the word "commodity" is pretty accurate. A lot of
companies have jumped into the fray trying to sell products. This has created a demand for more channels to market with many of these
products. The result is that you have conduit/pipe and bearing/belt suppliers hawking high end motion components for 10% margins.
Politically correct or not, these guys often can't tell the difference between a tach and an encoder much less an AC motor and a DC motor.
Lower prices are great for the savvy technically literate buyer.

However, the "open" market for products is going to have some casualties - both on the consumer side and the vendor side. Consumers that do not
put forth a sound effort in engineering and evaluation will choke on all the problems they create and the Fat vendors who are not used to knowing their product well and charging a fair margin will see a dramatic fall off in business and ultimately change or die.

The information age is here, in many cases the vendor who only offers a channel to market with no value added depends on two things: 1.) The
laziness or inability of his customer to find the same product at a cheaper price. and 2.) exclusive territorial contracts to hold his
customers captive. That should cause a little fidgeting!

One thing the information age does not change . . . the need for competent and judicious engineering analysis and experience with the
products AND the applications. I have to admit it though, the internet allows one to come up to speed and be more knowledgeable in a shorter
period of time than ever before!

My 3 cents worth.

Ken Brown
Applied Motion Systems, Inc.

Matthew da Silva

With highly-engineered systems such as factory automatino and process controls, the use of the Internet will be subservient to the availability of information. In your email, you give a lot of important tips about applications in which not all purchasing engineers will have equal knowledge. this is the key to Internet business, as I see it. It is, equally, the reason for the rise in importance and visibility of subscribed lists. Due to this increase in public profile, vendors naturally take a few hits on the chin. It's a Darwinian thing. But, unlike you, Guy, most vendors prefer to stay mute. But the benefits to end-users of posts like yours is, actually, the whole point of this list. The standards wars will continue until the best solution for each type of application evolves until enough people know it, and trust it, and until it gets into the specifications as a reqiurement. As I said once before, a lot of the issue is education. It is a pity that more
information is not available online. The Internet could really boost fieldbus usage. There is, clearly, a dearth of competent content-developers.

As far as purchasing stuff online, there's a lot more to do than learn XML. Whole taxonomies beg development but, again, we see a dearth of
volunteers with commensurate taxological (or, ontological, a word that is the, incorrect, common method for describing this) know-how. With
adequate planning, it should be possible to implement automatically-updating catalogues and specification sheets. New names may arise to describe these 'documents' which allow end-users to narrow-down or widen the field of play in which vendors compete for contracts. If terminology is standardized, that would relieve load that purchasing engineers now bear and, instead of transfering that load back to vendors, the load would be taken up by the Internet. But, like any big, enterprise-critical construction project, it will take much planning and design before anyone will place enough confidence in the
structure's ability to bear that load. Anyone willing to contribute their knowledge and time?

Matthew, tokyo

David Lawton Mars

In a message dated 4/18/00 2:35:18 PM GMT Daylight Time, [email protected] writes:

> If terminology is standardized, that would relieve load that
> purchasing engineers now bear and, instead of transfering that load back
> to vendors, the load would be taken up by the Internet. But, like any
> big, enterprise-critical construction project, it will take much
> planning and design before anyone will place enough confidence in the
> structure's ability to bear that load. Anyone willing to contribute
> their knowledge and time?

I've been following this thread closely as I believe it raises many interesting topics.
Regarding your question about time and effort to put information on the internet, I'm currently working on that very topic! I'm a self employed engineer predominantly involved in motion control, plc's and hmi's. I'm collating my knowledge from the past 10 years or so and I'm
designing a web site to provide technical tips and info for a variety of applications and platforms I've used. It's still early days, but if anyone has anything that may prove useful that
they're willing to send me I'll incorporate it into the site - I will of course acknowledge those who wish to be acknowledged for their input.
I reckon it will be a few months before the site goes "live" but all information is more than welcome. My direct e-mail is
[email protected] for anyone interested.
Thanks in advance for your input