You can go up to 600m if you really want to.
Standard setup with Master, PSU and slaves is 100m.
Put an Extension plug on the end and it it increases the range to 200m.
With 1 repeater you need 2 PSU's and the range is increased to 200m.
Add in extension plugs and you can increase it to 400m.
Max is 2 repeaters in series, 3 PSU's total (one per repeater-segment) is 300m.
Add in extension plugs you can get 600m.
Thats all in series. If you want to go T or parallel, then make the T-point in the segment that includes the master, add a repeater and PSU and that segment of the T can go up to 200m.
This limited to max 62 slaves.
This info should be somewhere on Siemens site. Got the paper version of it right in front of me.
Edit: If you are going that far, it might be best to add the extra 24V DC cable to the circuit....