Re: How to calibrate Quadrature Encoder signal
Hello, Thank you for contact National Instruments. Here are some links to documents on our website that should be very helpful for you in understanding your encoder and application. One of these links is even an example program for LabVIEW that you may be able to modify to do exactly what you need. http://zone.ni.com/devzone/conceptd.nsf/webmain/665470207873076386256B35007957A2?opendocument http://zone.ni.com/devzone/conceptd.nsf/webmain/4BAEC2BEE4C02FAD86256802007B8B5C?opendocument http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3E5BD56A4E034080020E74861&p_node=DZ52326&p_source=External Regards, Bill B. Applications Engineer National Instruments
How to calibrate Quadrature Encoder signal
I have PCI-6601 and CB68-LP connector. How can I use these to interpret quadrature signals coming off an optical encoder (to sense the angular position of an-observatory dome). The encoder is 16-bit(don't know what this means in terms of PPR). I want to have a display in Labview that will show me the position of the dome in a fraction of 360 degrees with some reference(true north?), the dome rotation controlled by a three way switch(clockwise-off-anti-clockwise). I don't have much experience with labview and any help will be appreciated.
Re: How to calibrate Quadrature Encoder signal
If the encoder is 16 bit then it would seem that: - 360/65536 =3D 0.0054931640625=B0 or there abouts. You can break the project down into two halves nicely. 1) Hardware interfacing. 2) Software read out. The hardware interfacing means two basic things: 1.1 What is the encoding technique 1.2 How are the signals conditioned for output to an external device. The software is classic: 2.1 Input 2.2 Process 2.3 Output The optical encoder could be one of a few types and you need to understand both the signalling / interface and the coding technique to progress further. A good start will be the manufacturers data sheet for the product. Contact the manufacturer. Once you understand the coding technique you will then know if the unit is absolute or relative. This will then allow you to determine how you can point to true north (easily with an absolute encoder, it always tells you exactly where it is). If it is a classic quadrature encoder then the relative phase of the reference and movement signals gives you direction. Counting transitions gives you realtive movement. But if the power went off on the PC. you don't know where you are unless you go to a home position! That could be 359=B0 round !!! Good Luck
