Motor vibration

[djhazeleger@mindspring.com]

Does anyone have problems with their stepper motors having a harmonic vibration at slow speeds? I am wondering if this is normal and if thier possibly would be a solution, also I have noticed while jogging, if I press the space bar to stop movement, and then resume the steppers will just stall and vibrate. This is true with the motors completely unattatched to the machine. If I quit cut and then jog,the motors start fine.

[birdsofplay]

If your motor speeds are too high, stopping and starting from the middle of a program will stall
because there is no "ramping".
The space bar stop is more of an emergency feature
than a "tool" to use while doing work.

At certain step rates steppers wont run under noload condits because of harmonics.

I've never had my SB NOT run under load except when the speeds were set too high or the
cables were too tight.

How low is real low ?
I've run mine down to .1 ips, but it burns !

It's best to find the highest cut speed, as
the much of the heat will be carried away with
the chips.

I'm not sure I can even go fast enough to keep cheary from burning. :-(

[john@pcjet.com]

I won't go too far into stepper motor theory, but one factor that affects stepper motor performance is resonance. By insulating your motors from the carriage (IE rubber washers) you will reduce the resonance and increase your reliability.

John

john@pcjet.com (mailto:john@pcjet.com)
www.pcjet.com

[Ted Hall]

Hi Dirk,
As indicated above, there are frequencies that steppers vibrate (resonate) at worse than others, you might just try changing the speed. As Bob indicated, the problem not starting up after hitting the space bar is that there is no ramp to get you up to jog speed, so the motor is stalling. The new Version 2 software (beta 8 downloadable here) 'resumes' with a ramp whether you stop with the space bar, the external e-stop, or using the 'S' key for a slowed normal stop. In the software you are currently using you can use the 'S' key for a ramped stop and start which should also solve the problem.

[john@pcjet.com]

You can find more information (resonance) associated with loss of torque at http://www.euclidres.com/apps/stepper_motor/stepper.html

John
J.E.T. Enterprises
john@pcjet.com (mailto:john@pcjet.com)
www.pcjet.com

[bruce_clark]

John:

Not to sound ignorant, but explain to me how
isolating the motor from the frame via rubber
washers affects the resonance frequency of the
stepper motor.

If anything, the more rigid the motor is mounted
to the frame, the better (more positional accuracy
from the motor not wanting to twist, which also
allows more torque to be transmitted to the drive
mechanism).

Resonance is known as "mid range instability"
and is combated not by rubber washers but by
adding friction/load to the motor. A flywheel is
the most common fix.

Another _rule of thumb_ is that stepper motors
LOVE friction! Some stepper motors will not turn
at all (they will just vibrate) until a load is
added and then they work PERFECT!

Bruce Clark
bwclark@centuryinter.net (mailto:bwclark@centuryinter.net)

[john@pcjet.com]

Bob,

Here is a little sample of the manual that comes with our Chain Drive that talks about resonance.

To eliminate or decrease resonance adding inertia would lower the resonance frequency, but would greatly reduce the maximum system acceleration. b) Friction would tend to damp the oscillation, but add more torque. c) Start/stop velocities higher than the resonance point could be used if they have sufficient usable torque to accelerate the load. d) If a rigidly mounted stepping motor is rigidly coupled to a frictionless load and then stepped at a frequency near the resonant frequency, energy will be pumped into the resonant system, and the result of this is that the motor will literally lose control. There are three basic ways to deal with this problem: Changing to ministepping and microstepping can minimize resonance vibration. The motor itself does not change if a microstepping drive is used. The motor is still the standard 1.8’ stepper. Microstepping is accomplished by proportioning currents in the drive (higher resolutions result). Mechanical dampers can help if sized to the load, but at the expense of system acceleration. . Elastomeric motor mounts used with elastomeric couplings between the motor and load will decrease resonance and must be used if the motor is mounted to the drive carriage.

This is why we use rubber mounts on all of our steppers. You can order elastomeric motor mounts with the elastomeric couplings, but I find that standard rubber washers do the trick.

John
J.E.T. Enterprises
john@pcjet.com (mailto:john@pcjet.com)
www.pcjet.com

[bruce_clark]

Randy at JET :)

Is the chain upgrade using elastomer couplings?

This solutions works at the expense of torque to
the driving mechanism (pulley on cable, pinion on
rack or sprocket on chain).

All things being equal, I still believe that you
(people in general, not you specific) are better
off RIGIDLY mounting the motor and putting a load
on the motor. Now, if the stepper motor NEVER
chained directions, then I would agree 100% with
this approach, but since the motor DOES change
directions, you are allowing room for backlash to
creap in (no matter how slight).

Just my view, not neccessarily the right one.

Bruce Clark <--- it me, not Bob
bwclark@centuryinter.net (mailto:bwclark@centuryinter.net)

[birdsofplay]

Maybe Tedd can tell us IF microstepping is even
being used in the SB program(s).

I'm still on the fence re this issue.

Bob Neitzke <--- not Bruce :-)

[arthur_ross]

Another question/comment about rubber mounts- they would tend to thermally isolate the motor, and if I recall previous posts, the ShopBot motors get pretty hot during constant use. You could add a heat sink to the motor, but it's easier/cheaper to use the existing frame as a heat sink.

Arthur Ross<---not Bob *or* Bruce :-)

Deltamation Inc/www.signsontap.com

[john@pcjet.com]

Snicker....you guys are a riot...ok, Bruce..., not Bob, and not Arthur...grin

No, we only suggest to our customers that if they are still having problems that they might want to try the rubber mount. When I say rubber mount, I'm not talking about some huge thick thing, I am talking about a pretty thin rubber washer to insulate the motor from the carriage. As BRUCE (snicker) stated, you can add a friction load, but the thin rubber washers worked for us. It would be nice to have comments on the microstepping alternative.........can we do it?

As for the heat, since the Chain Drive is geared higher than the pulley system and the torsional load is minimized (compared to the cable), the motors don't heat up at all.

Thanks to all, this is a more friendly discussion than others....grin

John
J.E.T. Enterprises
john@pcjet.com
www.pcjet.com

[rgbrown@itexas.net]

I am really having some problems understanding this thread. I thought the stepper motors worked better at higher speeds. Greatest power consumption was in the 'hold' mode, then is when one would need greatest heat disipation, the reason the 'Z' ballscrew motor would heat up. By gearing the motors, several things were accomplished; better resolution; heat disipation through the base; more pull force and increased holding power.

johnnyt is saying gear higher and insulate the motor. That would do every thing I have been taught about machinery and engineering wrong. And, the laws of thermodynamics must have been changed, probably the last Congress did that, damn politicians.

Confused,

Ron B - rgbrown@itexas.net (mailto:rgbrown@itexas.net)

[arthur_ross]

Let's see if I can muddy the waters some more-

1. If you can eliminate the resonance, slower is probably "better" (more torque). If you can't eliminate the resonance, the "best" speed is probable above resonance and below where the torque curve starts to fall off.

2. With a chopper drive, the same current is applied to the motors at all times, and so the same amount of heat is generated by each motor. Is the Z motor set to a higher current? More Z heat could also be due to the less rigid coupling of the motor to the frame providing less heat transfer.

Arthur Ross
Deltamation Inc/www.signsontap.com

[john@pcjet.com]

Ok, here we go.....

There is more strain on the motor with the cable pulley, not as much with the larger sprocket (case proven by movement of carriage with power off). Not as much strain = less heat. As far as the insulation of the motor from the carriage.....if that tiny portion of motor that is in contact with the carriage takes away all or most of the heat from the motor (which the heat tends to build up on the top of the motor instead of the bottom) then call Intel and tell them we all have an idea for a new heatsink, they have been doing it all wrong, they should have been putting CPU heatsinks on the BOTTOM.....
The book on thermodynamics that I read mentioned heat rising, but maybe Congress did change that law too, making heat fall towards the floor.

As far as the earlier posts go, apologies to Bob who thinks I am slamming him for other posts by typing his name....it was an honest typo....he should be flattered that he was on my mind.

John
J.E.T. Enterprises
john@pcjet.com (mailto:john@pcjet.com)
www.pcjet.com

[rgbrown@itexas.net]

Gee, they did change the laws, I thought only history was in peril. I am glad to hear conduction works the same way as convection now. This is a very educational forum.

Thanks for clearing this up,

Ron B.- rgbrown@itexas.net (mailto:rgbrown@itexas.net)

[john@pcjet.com]

CONVECTION: 1: the circulatory motion that occurs in a FLUID at a nonuniform temperature owing to the variation of its density and the action of gravity. b: the transfer of heat by this automatic circulation of a fluid.

Now, unless the steppers are filled with oil, I believe that convection is not an issue here.

As far as the conduction, the stepper motors that are with the cable drive system are mounted to the carriage in a way that only a very, very small portion of the case is in contact with the metal carriage. For conduction to work, a little more of the motor would have to be in contact.

Are you guys really having that big of problem with heat? I remember a user stating that they had installed 486 heatsinks on the tops of the motors....sounds like a good idea...

Today we have been running our Bot all day long will little or no breaks. When this discussion reached this point, I went out to the Bot and felt both X axis motors and Y axis motor, they were rather cool....the only motor that appeared to be hot was the Z axis motor...which still uses the stock drive from Shopbot.

What can I say..? The rubber mounts work for us. The Chain Drive works for us. Our methods work for us.

John
J.E.T. Enterprises
john@pcjet.com (mailto:john@pcjet.com)
www.pcjet.com

[Ted Hall, ShopBot]

You guys are so busy here, it's hard for me to keep up ...

On the question of whether we micro-step ShopBots, the answer is no, not at the moment. We half-step them. This helps some with the resonance, though not as much as micro-stepping.

Micro-stepping is attractive. For a ShopBot, it might offer an alternative for greater resolution and would reduce the rattle. We've played with an Allegro micro-stepping driver similar to the one we currently use for half-stepping. The trade-off as always is cost. The driver is more expensive. And, more importantly, we would have to completely redesign our control system in order to generate the higher rate of stepping commands that would be required (see specs on steprates in the developer section). There are some alternative approaches which we will probably continue to evaluate.

But we like the straight forward approach we are currently using. It keeps most of the control in the PC; which means it is easy to update the whole system with software updates. It works within the range of serial communication capabilities; which means inexpensive and relatively long attachments to the tool from the PC. And it's within the capabilities of old slow shop computers. The costs are appropriate and with R&P we are at a relatively high resolution for woodworking, so I can't see much to be gained by the resolution aspect of micro-stepping. The single downside is vibration and I think for practical purposes (especially with the new R&P systems) this is largely aesthetic. We have not noted any working speeds where resonance has significantly compromised power.

[arthur_ross]

Ted-

Thanks for all the great info! It's good to hear the straight stuff from the developer.

Just to take this thread in a whole new direction-
How hot is too hot for a stepper? I've run various steppers hot enough to fry ____(mostly my fingers when I touch them) and work fine, but I've had others die from that kind of use. Any thoughts about stepper heat specs, or the long term degradation of the lubrication, bearings, etc., and failure modes? I suppose the puddle of molten aluminum on the floor should have warned me... :-)

Arthur
Deltamation Inc./www.signsontap.com

[Ted Hall, ShopBot]

Hi Arthur,

Well ... I've heard people say that if a stepper is not hot, it's not working hard enough. I've played with lots of them, but my extensive experience is only with the small Vexta/Oriental motors that we put on ShopBots. They are rated for a max ambient temperature of 120F, a maximum surface temperature of 212F, and a max coil temperature of 260F. So ... 'hot to the touch' should be right in the working range. We have upwards of 1500 stepper motors out there now. We've had a motor or two that has had a shaft that was damaged from being dropped, and one or two with bearings that seem to have failed after running in an environment with -lots- of foam or solid-surface dust. But we've never had one of these motors fail from overheating or otherwise burn out. We may be a bit over-confident about them, but we don't worry much about the motors running warm ... for that matter, we don't worry much about the motors at all. Stepper technology has been around a long time ... I get the feeling that the good ones are well developed and robust.

[arthur_ross]

Ted-

Sounds good to me. The motors that fried were out of my junk box, so they may have already been damaged, or really old technology.

The new ones I use (Mycom) have not had problems, so I guess I can abuse them without fear of frying....

I wonder if there's anything to do for dust protection of the bearings, or would the cost of a "boot" protecting the bearing be more trouble and more expensive than the once-in-a-great-while replacement of a motor.

Arthur
(Mighty Destroyer of Motors....:-) )
Deltamation Inc./www.signsontap.com

[dthorpe@gte.net]

Ted or Gordon,
Can you give us the torque specs on the standard sb stepper? When changing over to more powerful steppers, does anything other than installing a second x driver board need to be done? What would you say is the ideal ratio for the thrust box? We are currently running 4:1 and have plenty of power, however we would like a bit more speed. The new software allows us to run at higher speeds with less inertia related movement of the machine, ramping is critical and the new software with its "look ahead" function really smooths out those 3D raster toolpaths. ShopBot rules!
den

[Ted Hall, ShopBot]

Hi Dennis,

The standard stepper motors on the cable-drive ShopBots are 120oz(holding torque); on the rack & pinion tools we use 187oz motors ... and we've puttered with some bigger ones. Note that holding torque expresses the power of the motor at its slowest speed (i.e. stopped). It is one of the specs you are interested in. The second is the shape of the power curve. The more optimal the motor for our use, the higher the step rate the motor will hold its power to. Regular steppers tend to have a pretty sharp power drop off in the area of 1000-2000 steps sec. One of the reasons we like the little Vexta/Oriental motors so much, is that they are at the high end -- their power fall-off does not occur until about 2000 steps/sec which is about our highest step capability. It is the power at a high step rate that allows you to move the tool around quickly. We've found that at slower (cutting) speeds (e.g. .75in/sec), if a motor has say, a 25% higher holding torque, it will acutally deliver a measurable 25% increase in force. However, the higher speed performance of the tool (i.e. top jog speed) is directly dependent on where the power drop-off (re: step rate) is. Often a big motor will have more trouble at higher speeds, perhaps because of size and momentum factors.

In the case where a gear reduction box is appropriate, such as with rack & pinion (in order to allow a good sizing of the R&P), we're thinking that 3:1 to 5:1 seems about right. The tools we are shipping have a thrust box with 4:1 ... but variations around this seem to work just as well.

In terms of gearing, what you are more interested in is the ultimate ratio of the stepper rotation to the tool movement (which would include your final power transmission link such as the R&P). For our system, keep in mind that you will be working in the 0 to 2000 step/second range (there are 400steps/motor rotation). Under about 1000 steps/sec you will have just about full power (at least with the Vexta motors), above this speed, power will start to drop off -- with some motors more quickly than with others. ShopBots seem pretty well optimized in the range of about 350 to 750 steps/inch. Note that as you increase the steps per inch, you increase the power, increase the resolution, and limit the top speed (by step rate). As you decrease the steps inch, you decrease the resolution, decrease the power, but increase how fast you can go -- until you hit the limitiation created by reduced power. It's all a question of trade offs. I'm working to get a little graph of this posted.

On a non-encoder ShopBot (e.g. R&P or ball screw) multiply your Unit value for the X and Y axes by 4 and you will have the number of steps/inch. Multiply the Z axis by 1. (For an encoder tool, the unit values are related to encoder 'tics' and only indirectly to steps, though on a standard tool there are approximately 500 steps/inch).

[Mark Walker]

Hi, everyone,
Mark here in the uk. I'm having a lot of trouble with my y axis not traveling whilst in some positions on the x rails!!!
Does anyone else have a shopbot that plays a tune or is mine the only computer string instrument in the world?
I'm wondering if it is normal for the pitch of the motors to alter greatly whilst doing air cuts with no forces applied to the tool. Is this the resonance that has led to all the debate. My shopbot needed new cables fitted all round so I started to replace them and got only as far as the y axis when I tested it for power. Unfortunately there is no power at all in some areas across the table. The machine struggles to limp from one side to the other at any speed I set. From .4"/sec or jogging at 3"/sec. There is no twist or binding at all without the cable fitted and the carriage glides from one end to the other. I have tried powering the motor from the z driver board with no problems, I have used the cable from the z on the y driver and got problems. Anyone. And by the way John at Jet. I am sure that air is a fluid when you are discussing convection, we have convection heaters and heat sinks, air turbulence etc. Maybe!!!
Ive made up some carriage assemblies with neat little bearings so-so-so smooth!! anyone else done the same ?
Mark UK.

[dthorpe@gte.net]

Hi Mark in the UK,
The first thing that endeared me to my shopbot was the "tune" it plays. I'ts to bad you always have to run that screaming router! The first thing you have to do is get rid of that cable drive. We have one that is chain driven (with gear box reduction sorry john :() and one that will be driven with steel reinforced, open ended timing belt. 3:1 to 4:1 reduction on the boxes seems to work the best. What type of bearings are you using? We're using the bishop-wisecarver's (like the newer shopbots have) but the twist is that we're using them with the hardened steel track that they are supposed to be used with. Very Smooth and Very Accurate! Once we get the new machine running we'll post pictures on the ftp site.
shopbot rules!
den

[john@pcjet.com]

Dennis,

No need to be sorry. We are happy that individuals had the opportunity to incorporate on our chain drive idea and make improvements that they see fit. Since early last year, when we released the idea on the old forum, we were met with great opposition. Now that the chain drive family has grown to a large population, it has become an accepted practice. By producing our video on the chain drive we knew our audience would be either:

1. the "do it yourselfer" who can reproduce the idea and make modifications as needed.

2. the individual who can't afford to mess with problems, trouble shooting, etc. and is willing to pay for a kit to solve their problems.

Of course we would like more #2's than number 1's, but you have to expect that people will reproduce your idea.....just look at all the copies of Shopbot machines out there.

I think it is great that individuals realized that a chain driven solution can be more cost effective and reliable.

Recently our focus has shifted to new projects and products for the Shopbot machine. We are still supporting the chain drive solution (as always). Keep an eye on us as we will be posting our products (along with our sign shop store front) on our web site: http://www.pcjet.com
It is kind of bare right now because of the early season rush, but I will be updating it fairly soon.
I hope that other Shopbotters are having a very successful business season, if you need any information, feel free to contact us.

John
J.E.T. Enterprises
"We make your imagination FLY!"

www.pcjet.com
john@pcjet.com (mailto:john@pcjet.com)

[Ted Hall, ShopBot]

Hi Mark,

I know that Gordon has been working with you on your Y-axis problem. So I hope we have it dealt with at this point. Just to put a bit more info here:

Motor Tunes:

Yes, your steppers should make music. This is because as they are vectored in different directions, the step speed (music frequency) of each motor changes so that the absolute vectored speed remains constant. If the motor speed were not changed, a diagonal move would actually have a speed 1.4 times faster than an straight X or Y move with motors going the same speed. You can hear this most clearly as the motors change speed driving through a circle ... or just 'play' the ShopBot logo file "SBLOGO.SBP".

There is some discussion elsewhere on the forum regarding resonant frequencies. These are an important theoretical issue for steppers. But in the speed and power ranges that most ShopBots are working in, do not create practical problems ... basically because there is usually excess power at bad frequencies ... though, aesthetically, there are some speeds with more vibration than others.

Y-Axis Power Problem:

Given the data you report above, it sounds like there is a problem with the current driver in the control box. You've done the appropriate diagnostics of switching out the cables. If you take a look at the Troubleshooting section of the forum, under the Encoder section it tells you how to test encoders. This section also explains running in diagnostic mode where the encoders do not come into play. Testing the Y axis without the encoder would provide the definitive indication that we have a problem with the driver card or the connections to it rather than a problem with the interaction of X and Y axes via encoders.

[rwill40158@aol.com]

I'm new to shopbotting so please excuse the questions that may already have been answered. During X and Y travel (without the router turned on), I can detect a slight knock sound every 1/2 turn of the motors. Is this normal? It almost sounds like a bad gear tooth but I can't see any and it happens on both axis ( not Z ). Is this normal?

[SaintjohnBosco@yahoo.com]

Roger, check and see if your pinnion gear is tight enough. I have had mine come loose and it caused all kinds of trouble. Maybe it is just slightly loose and rocking back and forth. Just a suggestion. Make sure you use locktight to keep the treads from loosening.

[rwill40158@aol.com]

Further to my knocking sound problem, I changed from a 486 laptop to a 60 mhz pentium and the knocking sound disappeared and the tool runs a lot smoother.

[ervineq]

I just finished assembeling our PRT 60x144 about 3 weeks ago. I am having problems with steeper motors, they are noisey ( kind of a clicking sound) and move a little jerky.
I have talked to tech support about it, they suggested motors were out of level or gears weren't tight. Checked the gears (OK) shimmed the motors both vertical and horizontal. this helped until I jogged gantry home (JH), then the same old BS all over again.
Not being one to give up easily and ask for help I rechecked everything, still good.
I have found that ( some times but not every time) if I close software and shut down the control box, then move the gantry (by hand with gears engaged) to stop bolts,turn the control box back on and re-open software I can hit K and jog with arrow keys the length of the table smooth as silk.
As soon as I do jog home (JH) then try to jog again the length of the table it starts the same old BS all over again.

Today I removed the motors completely from the gantry typed in (J,X,96) and the motors make almost as much rough noise as they did when they were bolted up and engaged.

Any suggestions would be greatly appreciated.

P.S. This seems apparent on both X and Y axis, I also tried grounding the gantry to control box. No such luck!

[logical@gmi.net]

I had the same problem. It was the fact that I was running the shopbot program in windows. I have had my bot for about a month and it just started happening one day. I now run shopbot in dos mode and it works great. I also have another computer that I hook up to the bot and have no problems with the clicking noise out of it.

Try running in dos mode or switching pc's somehow. I'm sure it will help.

Wes

[support@shopbottools.com]

Hi Glenn,

Has someone here checked your PROBLEM.LOG file for possible conflicts. It does sound like a problem with how the computer is set up. I'm guessing that we'll find a conflict we can quickly fix ... There is a section in the manual on configuring your autoexec.bat and config.sys files, but if you send the file to support@shopbottools.com (mailto:support@shopbottools.com) we should be able to sort it out in short order.

On another note ... try not to push the gantries by hand while they are plugged into the control box. They are powerful generators and can damage the drivers.

[ervineq]

Thanks eveyone for your replys.

I rebooted in DOS mode and eveything works fine.

I will email log file asap.

Thanks again
Glenn

[rikalife]

Motors not working, they seem to be stuck, they sound like they are going to move, but stay still, only Z motor runs. This happened from one they to another, they were working fine yesterday.I run my prt96 from windows. I unscrew the motors and tried off the table, same thing, but connected motors not working to Z and they did work, any suggestions, thanks.

[Brady Watson]

Ricardo,

I had a similar problem from time to time and was unable to resolve it. I found out that other botters were having the same issue with the motors making a laboring noise and not moving smoothly.

Here's how I fixed it forever...From my archives...

My numbers were between 45 and 90 when I sampled. Yours may differ.
---------------

Timing primarly influences how ramping is done. If we don't get a good timing measurement, then the tool may either ramp very slowly or too abruptly. The measurement is typically only a problem with a fast computer in Windows, or a computer that is running a number of programs. Assuming you are running in Windows, here's how to deal with it (the new ShopBot software will not have this issue):

Use the [UP] Command to re-sample the computer speed half a dozen times. Write the values down and look through them.

Throw out the extremes, and take the average, then decrease the number by about 10%. Let's say you got about 500 ... so we'll call it 450. OK ... let's put this number to use.

Find the file called SbCut.bat in the Sb200 folder. Open it with a Text Editor like Notepad. The last line of the file currently

looks like this:

sb.exe %1,,,,

Change it so it looks like this:

sb.exe %1,,,{your number}, e.g. sb.exe %1,,,450,


This procedure will hardcode the timing check on your computer so that windows does not get any strange timing values.

Funny timing values are usually the cause of uneven ramping.

-------------

Hope that helps,
-Brady

[gerald_d]

Ricardo,

I get the impression that you had a good ShopBot yesterday, you did not change any settings, today your x and y motors are "stuck" (all 3 of them), and you only have a working Z motor. If you move a "stuck" motor to the end of the z-cable, then it works. Hope my summary is correct.

I can't understand why 3 motors suddenly get stuck and only one keeps on running. Did something change in the settings? Was the machine struck by lightning? Was the bundle of cables pulled out of the control box?

The only things that I can suggest is to blow out all dust out of everything and carefully check all cables and connecters. While doing this, think if there was a big event......

[Brady Watson]

Gerald,
My machine has the exact same symptoms when I get a 'low' number. Only the Z moves and the X and Y motors either sound labored or struggle to move.

I no longer have this problem after hard coding the timing value.

-Brady

[gerald_d]

Brady, can you tell us in more detail how you sample your numbers? "My numbers were between 45 and 90 when I sampled"

[Brady Watson]

Gerald,
As posted above:

"...Use the [UP] Command to re-sample the computer speed half a dozen times. Write the values down and look through them.

Throw out the extremes, and take the average, then decrease the number by about 10%..."

[gerald_d]

Aha, figured it out that UP equals Utilites -> Process Speed while running under ShopBot software. Thanks