incremental encoder

[ziadsaka 0]

how could I find out the direction of rotation in an encoder connected to plc,need example program

[Seppo Alanen 0]

1'st draw the channels 'pulses' cahannel A above and Channel B under it as 90 deg offset. 2n'd go from left to right and when B goes up take one-shot for it. If Channel A is true, you are going to fwd. then go from right to left and when B goes up take one-shot for it. If Channel A is false, you are going to rev. Now you have one shot/pulse for both direction. Think more! You can do 2 shots/pulse and you can do 4 shots/pulse-cycle indeed for both direction. So if you have encoder f.e. 20 impulses/round, you can get 80 shots/round and you have 4 times preciser resolution !

[jacekd 0]

However if you have this encoder connected to a card supporting incremental encoders then this is usually done for you by hardware.

[Seppo Alanen 0]

Usually Counter-units are 'expencive'. If you don't have any need for fast counting, use digital Inputs and save your money. Edited 26 Mar 2004 by Seppo Alanen

[jacekd 0]

So please explain what you mean by "fast counting" or how to find out if counting is fast. <>