Bit shift left functions

hi
I m trying to learn BSL and BSR. I want to clear my basics about Bit functions. Can anyone help me to understand that why do we use BSL and BSR and when do we use it?

Say you have a sensor that detects an item made of two parts--one on top of the other, which elevates it's total height. Now there's a sensor that detect the presence of the bottom "Part", and a second sensor that detects the upper part "Elevation".

Place the parts on a moving conveyor. When the bottom sensor detects, the upper sensor should detect as well. When this occurs, load a "0" into your BSL word address. When only the bottom sensor is triggered, load a "1" into the word. "Downstream" in the BSL the "1" will trigger an alarm or reject sensor to kick the incomplete part off the line.


Just one of many apps for a BS...

Thanks alot
I got that for what purposes we use bit functions. But can you please help me to learn that HOW do we use bit functions?

Use an encoder pulse or some event (timer or counter, etc.) to trigger the BSL or BSR. This will cause the shift.

Here is a little more info for you.

http://www.mrplc.com/kb/index.php?article=71