Reading encoder signal without using onboard controller

[Kalisto]

Hello

We are using an  E 6023 card and want to control an synchronous motor. We want to make a bodeplot by comparing the input signal with the output related to time.

The output signal is an TTL signal wich enters the card. How do we relate the TTL signal to time? There are example codes on the site but they use buffers, or just count the pulses of the TTL signal. How do you read these pulses and relate them to time and how do I know if it increments or decrements ( motor up and down)? If you use the motioncontroller on board of a card this transition happens automatically, but what if I want to use my own controller programmed in Labview.

The input signal is between -10V and +10V wich represent velocity, so I have to compare this input with the output signal.

Is there anyone who can help me with this

Thanks a lot

[demux]

Hi Kalisto,

There is an example which ships standard with the driver that uses one counter to measure the frequency of a TTL signal. Which is directly related to time.

You can find it at: *\National Instruments\LabVIEW 8.0\examples\DAQmx\Counter\Measure Digital Frequency.llb

If you know what the frequency of your TTL signal is and you know how many pulses/rev. your encoder has, you can calculate how fast your axis is turning.

Measuring the position of your axis is also a standard example which ships with the software. Knowing the direction in which your axis is turning is normally done with the signal that your encoder puts out. It normally has two outputs, A and B.
A and B are shifted 90° in phase, depending on which pulse, A or B, reaches your counter first you can tell in which direction your axis is turning. This is all implemented by standard in the vi you can find under the examples...same as above ...........\measure position.llb

Regards,
WVH

[Aeneriz]

Estoy intentando controlar un motor paso a paso y que tiene un encoder incremental asociado. Quiero leer la posicion del encoder ( A, B, Io) con la tarjeta PCI-6023E, hay ejemplo en el directorio C:\Archivos de programa\National Instruments\LabVIEW 8.5\examples\DAQmx\Counter\Measure Position.llb pero no me funciona,

Podria alguien ayudarme con este problema?