I have a Fadal 6535 with Siemens Sinumerik 810D Control. Its runs very fine but sometime during tool change, it stops and doesn't change the tool and then it doesn't let me do anything. and if i restarts, it forget all the tool's location.

Explanation:- If i program machine with more than 1 tool, for couple of hours it runs fine but after it stops changing the tools, spindle goes to tool change position, then it doesn't do anything. There is no alarm on the screen except control argument; "50102 ATC ACTIVE". So, after that it doesn't let me reset the machine or change it to handle mode or anything. The only thing i have to do is switch off the machine from back. After restarting the machine, it forget all its tool's location and start putting wrong tools.

Please help.