I get a weekly email from Siemens Tech Support. It has Tech notes updates etc. This week they have the following example of indirect addressing and looping.
So here is a link
http://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=19345564&caller=nl
Entry ID:19345564
So here is a link
http://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=19345564&caller=nl
Entry ID:19345564