GSR

How do you pre determine the number of module at the analyzing (beginning) phase of the program?

Should I consider that LV is similar to other OOP like Java?

I just start to prepare CLD exam. I plan to take it next FEB or MAR.

I spend 2 mins to read what is the "traffic light" exercise. It seems not relate to intermediate II course work. Does it mean intermediate II is not useful for CLD exam? Please give some suggestion

TTHHAANNKKSS

I know there are channel A, B (maybe also Z) in a regular optical encoder. I just have a encoder card which say it is for Phase A+, A- , B+, B-. I guess Phase A = Channel A, but what is the + and - mean???

If you have it and want to sell it for a poor guy with a low cost, please reply this message or PM me

Thanks

Something like this?

Yes!!!!

Dear all,

I am building up an analog circuit for Electromyography (EMG) data collection, but I have to put isolation between the circuit and the human subject. A possible solution may be opto-isolator, does any opto-isolator support analog input and analog output?? I read wikipedia which says opto-isolator is using an LED inside the chip. If so, there may have some forward vlotage bias in the signal???

I got CLAD 10 month ago, and want to do CLD exam next March!

I plan to read "The LabVIEW style book"

I plan to work on all the exam exercise from ni.com

I plan to get coupon from Developer day (I call ni today, they still have not decided the developer day locations)

What else I need??

How long do you wait to get the result??

Ok I have another idea for you. You need to invite Mr D and your boss out for a drink after work.

Does not work!

Mr.D. schedule

Mon, WED 9:30- 10:30 , then work outside for 5 hrs, then go home

TUE, THU 10:00 - 14:00, then go home

FRI 9:30 - 11:30, then go home

How can we go to drink after work???

[/b]Wrong answer.

"What do you mean "seem"? is the right answer.

Wrong answer.

He works here? is the right answer.

Does anyone else find it a bit strange that

a) The wife is at work.

b) Shes very confrontational.

The wife is at work. -- His wife come because she uses the lab equipment for her personal use

Shes very confrontational -- She and Mr.D. are only 22; and she acts like 16

Correct answer is Mr.D works here but not even show up and do nothing

I'm ROFL right now.

Please NO ROFL! I need your suggestion!

You blew it, you are now Mr. D's slave

Help me. Please.

"oh what a tngled web we weive when first we pratcie to decieve." (W. Shakespear?)

1) Stop lying, you are making ot worse on yourself.

2) Talk to Stupid and share your thought and feelings.

3) Try talking to Stupid with a common person that you both respect.

4) Talk to your boss.

When you are doing your talking don't accuse or name call. Confess your short-coming and your concerns for Stupid.

So speak the truth, and be honest with your feelings both in your internal dialog and your outward expresions.

Ben

I change Stupid to Mr.D to make it clear, thanks

"So speak the truth, and be honest with your feelings both in your internal dialog and your outward expresions" <== Is that really OK in real world??

If you have read my previous stories (), here is the update

Stupid name is Mr.D

Mr.D wife talked to me in front of stupid and another guy,

Mr.D wife: GSR, you are working so hard and make "Mr.D" seem do nothing

Me: I am working so hard, because I always make mistake, so I need to fix them ( I am too nice to her)

Mr.D wife: Do you mean "Mr.D" does not work?

Me: NoNoNo! I just mean Mr.D never makes mistake ( Right, he never, because he never work. OR I need to stand behind him when he works)

TODAY

My boss come to me and ask me just set up everything for the "Mr.D" both building electronic hardware and programming. I say OK! But I have no clue why I need to help this guy. Should I just tell my boss that I really don't want help him because "Mr.D" has already said I am working so hard

Please teach me what should I do

What do you think about them?

I think (My information may not be right, just for discussion)

LabVIEW

• A few small/middle size companies specifically do LabVIEW programming business
• Easy to use to communicate to hardwares, especially NI hardware
• Relative easy to interact with other programming language (talk to Matlab, etc)
• The language itself has the same tones for all it toolboxes
• Those sale people are extremely hard sale (e.g. we have a toolbox do exactly what Matlab does; and the price is only 20% of Matlab)
• technical support people are nice
• Graphical control is unknown. I am not sure how to use LabVIEW to do some graphic control, like draw a sun and a house. Can we do that??

• I could not find any companies specifically do Matlab/Simulink programming business
• Easy to use to communicate to many different company hardware IF the cards are support (I have an NI card which is not support by Matlab)
• Not sure how to interact with other language. I did use it to interact with Java2D which was OK. However, Simulink only allow to use C++ to do real-time graphic which needed to do many setting to communicate in between each others (I still don't know how to do that)
• In term of the tone of the language, Matlab is fine. Simulink is........... (I will need a $2000 toolbox to do running average under realtime window target. Stupid)
• Those sale people are ....... (They processed my thousands of dollar business two months after my request.)
• technical support people are too too nice. I thought I was talking to my maid. It is good if you have any unhappy thing happened, then you can called them

Attention LabVIEW Programmers! VI Engineering may have an opening soon...

Does it support working VISA? and does the job location at MD?

What should the stupid ask me stupid question again, what should I say??

A) I told you last time that you should do this this this (the solution) <== I used a couple times

B) You think I am working too hard. I am working hard to spend hours or days to find out solution, so you don't have to think and just need to come to ask me!

C) I don't know

D) I am too busy right now. Sorry

Any other suggestion??

I have a labmate. He just finished B.S.; and thinks himself is a smart person . He is lazy (Only see him 12hrs a week.) . The things I teach him need to teach him again and again (e.g. sensors are needed to connect gounds; how PCI board connection. I even need to download the same data sheet again and again for him). 10 questions a day. Make a only 5 transistors circuit take a week and a few hours of my time to do problem solve for him . OK! fine (I am just too nice)

My boss may want to motivate him, so tell him that his project is very important. The stupid labmate came to talk to me and tell me that my project is not the lab direction; and don't work too hard . I am just thinking to take over his small project after I finish up my stuff.

Thanks

Dear all,

My boss asked me a question this morning. He wants to create a RLC circuit to control motor current to mimic a mechanical behavior. The behavior is a mass with two stiffness - varying springs (which stiffness is proportional to the distance) on each side of the mass. Two input forces on the end of the springs respectively. When we add Forces F1 and F2 to the springs on both end, the load (mass) will have net force F1-F2. Moreover, the stiffness changes depending on how far the springs compressed.

Now, you have a motor, a voltage controlled current source and your knowledge to make the "current to torque ratio" in the motor system changes when you still able to control the torque preciously.

I doubt LV can identify two channels from the same sound card

I will try to use two sound cards to start with

Do the online practice exam. It will help

Using SCXI hardware with high gain and isolated measurement channels should help a lot as well. 60uV seems like thermocouple type measurements. It should be doable with x1000 or so gain, but use isolated measurement channels. There is a module 1125(?) that has isolated channels.

Neville.

Is EMG - Electromyography (EMG) is a technique for evaluating and recording the activation signal of muscles.

I'm not really familiar with the MC3479. It looks like it might be a fairly standard stepper driver, and most of them work about the same way.

To answer your questions generally, steppers are fairly simple motors and are easy to control. That's why they are so popular.

To keep a motor in a constant position, you 'may' have to keep the current on. It depends on the configuration of the load. A stepper motor will generate no torque without current. But if your load is self locking, such as a horizontal motion or a vertical motion with a high pitch drive screw, it may stay in position. Another option is to use a relay brake that engages when the current is shut off.

If your load is too heavy, the motor will stall. A stall in a stepper motor is usually easy to detect just by the sound it makes. Most stepper motor drivers have a stall detect feature, where an encoder is attached to the load and if the encoder doesn't keep up with commanded position, the controller will detect an error. If your load is too heavy, there really isn't much you can do to correct it other than get a bigger motor. Slowing the velocity and acceleration can help some, as can changing gear ratios, but that doesn't always work.

Does your application require you to start with an MC3479? There are many manufactures of stepper motor controllers that would save you a lot of time instead of building your own.

Thanks for your reply

Yes! I have to use MC3479.

Now I can control it, but I still need to figure out how to control it at varying speed

"Noise Reduction Techniques in Electronic Systems" by Ott is a wonderful book ofr trying to work with noise in your signals. He analyzes most of the "noise" conditions you can run into starting with Maxwells equations and applying boundry conditions and then derives "Rules of Thumb" for each.

In summary he suggested in order

Eleminate the noise at its source (is a DC motor with funky brushes?)

Reduce the magnitude of the noise source (a well chosen pasive device may supress the noise)

Contain the noise inside a shieded container

Prevent coupleing (move away from noise source)

Exclude noise from logic (shielded box)

etc with the last choices being filtering.

So concentrate on fixing the tredmill first.

Ben

I like your summary! Thanks

Eleminate the noise at its source (is a DC motor with funky brushes?) <==== Cannot do it

Reduce the magnitude of the noise source (a well chosen pasive device may supress the noise)<==== not sure how to do it

Contain the noise inside a shieded container <=== cannot do it because it will break the treadmill

Prevent coupleing (move away from noise source) <=== cannot do it because the subject has to run on the treadmill

Exclude noise from logic (shielded box) <=== I did; and also improve the whole shielding system a day ago