Keith,
I currently am using an older version of Eagle. It's pretty good, but since we're doing some budgeting and have some money available, I wanted to see what I could get in a more comprehensive package.
Dan,
I wouldn't say our boards are overly complex. 4 layers max. Largest size would...
Hi Keith,
This is good information, and you're probably correct. I use the LTSpice 4 simulator off and on and it's pretty good. Of course, you have to go searching for spice models for other manufacturer's products, but it's not too big of a hassle.
If I could ask, what do you use for Pcb...
itsmoked,
Do you feel it is a better option to purchase a good capture/pcb layout solution, and buy a simulator separately? Or do you feel that simulation is not important?
As for pricing, I'm not sure what the company budget is yet for this year. I don't think 5k would be out of the question...
Hi folks. Wonder if you guys could chime in on some design suites. Looking for a suite where I can do schematic capture/simulation and PCB layout/design. I see that NI Multisim suite would do this for me. Any other feasible options? Also, I should note that I would love to be able to do thermal...
Well Gunnar, it seems that the application we have, the guys are using just a cheap, PWM controlled flow control valve. This valve is supplying flow to the directional valve, which is on/off.
I agree that it would be much more convenient if the valve had a feedback signal for position, but...
Hmm...well, I tried to do some modelling of the coil I have here. However, the step response of the coil shows that it is behaving almost like a pure inductor (minimal resistance), thus a first order system. Is this something that I am able to compensate using a PI or PID contoller? I don't...
Well, Curt, better late than never!
I will admit (sheepishly) that I had not even considered using a PI controller in my firmware. I guess this is what I get for falling asleep during my controls classes. I will look in to this right away.
(start of ramble)
As for the feedback, the current...
Yes, Keith, that VND device does vary greatly in its 'K' factor. However, there are other aspects of the chip that we like. Since the product is still in development, alot can change, hopefully this current sensing method will be one of them.
Note that most applications will use a PWM of...
I will be controlling hydraulic fluid. Probably in the range of 2000 - 2500 psi.
I noticed that slip of the keyboard regarding flow and assumed you meant pressure. Thanks for clarifying though.
Mark
Thanks for the tip waross.
I'd like to say that I am extremely impressed and grateful for the help I have received here. Being a fairly new engineer (almost 2 years field experience) I am always looking for tips/opinions from more experienced people. Once again, thank you to all the contributed...
No, it probably wouldn't Benta. The problem I have with measuring current is the ever changing resistance of the coil. For instance, the user immediately uses full output and has 1.5 A flowing through the coil. If this is held on for 1 minute, the current would conceivably reduce to 1.25 A. If...
Hmm..seems like a neat idea...however, from some of the prices of differential transducers, that option is likely out! I will look into individual flow sensors, but it looks like I may have to balance out system accuracy versus price at this point.
Thank you Keith and waross for your input...
I probably should have read your post better. You would put the orifice after the valve, then make one connection before the valve and one connection after the orifice?
Mark
Hmm...interesting. Are you talking of reading the pressure back to the micro and compensating that way? i.e. if the differential was a certain size, compensate by increasing the PWM duty cycle. So, where abouts would the 2 sense lines from the transducer be connected? (forgive my ignorance...
Thanks for the response Keith. One thing I didn't mention is that the user will have a device with an analog joystick which he will use in order to vary the speed of the system, or 'openness' of the valve. Also, there is not one valve that will be used, as customers may use different valves. The...
