Robot Encoder Position
I've played with these a bit and found some useful documents in the past.

Have a look at the robot forum on it. 

Basically run the 'home' job on the robot, you need the absolute position from each axis and this is found on a sticker on the inside of the controller.
At the home position you should have all the ref arrows alligned.

If the home position has been lost the encoder memory is lost.  It counts 4000 points for each revolution - if the encoder memoery is lost it doesnt know how many have passed. 

Take the difference between the new and old encoder home position and divide by 4000 - this will give you how many it is out by.

the example given was:

Original home encoder count: -119771 New home encoder count (after lining up reference marks and setting the data for that axis): -95834 Difference: -23937 Divided by 4000: 5.98425 Therefore, number of revolutions out was 6 My new home position should then be -119771 + (6)x(4000) = -95771