I've got a HiT-18S (with a Sinumerik 840C control) that I've just recently pulled out of general reset due to some other issues. The machine seems to be operating normally except for when actuating the work piece clamp either with the foot-pedal or via M-codes. When the collet is physically open, the lamp on the machine will light "clamped", and vice versa when the collet is physically closed. M6 will close the collet, and M7 will open it.

I'm suspecting the machine is in some mode to clamp by the inner diameter of a part rather than the outside of it, however I'm unsure of where to look to adjust the setting. Any help would be appreciated.