Greycat

QUOTE (xzhengze @ Aug 20 2008, 03:41 AM) I've also had to do this as part of our project. Most Stepper motor drivers (controller) have 3 inputs /motor (step, direction, and enable). Step is usually a frequency (which correlates to number of steps of the motor) - if your motor has a step size of 200steps/revolution and you input 400Hz into the Step input on the driver - your motor will turn 2 turns per second (400Hz)/(200 step/revolution)=2 rotations. Direction is the direction of turn of the motor (obviously only 2) - like the previous poster mentioned (you will have to check out what your driver input level are and adjust (sometimes with hardware (relays and such)). If your lucky, the inputs will be TTL 0V-5V. Enable simply turns the power to the motor on or off - Beware - running a stepper motor at full amps in a full stop positions can be very hard on it. Most drivers have a idle current reduction setting for cutting the driver amperage in half (usually) when the motor is not turning but enable is left on. Now for step ... this controls the speed at which your motor turns. If you try to start your motor at too high a step rate, it will stall and not turn at all (but it will sure make alot of noise). You have to start turning your motor at a lower step rate, then you can ramp the frequency to give you higher speeds. This is achievable in a normal DAQ card (as I have done it) but you run into problems running under windows ... it is supposed to be a multitasking operating system, but it is more like a multi threading operating system ... you can generate a frequency using the digital outs, but you find very small pauses in the frequency as windows takes the cpu from labivew for other tasks (even just windows ones). I'm pretty sure, since the card you are using is designed to run stepper and recieve encoder inputs, that it will have the capabilities to procude a frequency and effectively ramp the frequency to run a stepper. I had to use a frequency generator, and just have a set frequency (not ideal but works). As far as actually talking to the PCI card from labview - this should be fairly easy ... first thing to do is look at the examples that ship with labview ... then if you are still having trouble write back to this thread with come more specifics . Greycat

This does do it, but it is with a call to user32.dll (which I don't think PDA versions of Windows have) .. I have seen this before and it was a help. I'm trying to just that ... except with PDA version of Labview, not the windows version. Thanks for your reply Greycat

Does anyone here know how to retireve the window handle via labview and dll call .. I know that you have to use coredll.dll function to do this but everytime I try I get an error message stating that "FindWindow is a missing VI or C file" :headbang: ... has anyone done this? And if so, please share your knowledge. I'm using a PDA with WM 5.0. Greatest thanks Greycat