Typically, Collet Chucks work in the reverse to a conventional Chuck. Accordingly, the open direction of the Draw Tube for the Three Jaw Chuck, is the closed direction for the Collet Chuck. There will be either a Hardware or Software switch to change the chuck gripping close state from External to Internal. The control needs to be set for Internal Gripping for a closed state for the Standard Chuck, to satisfy a closed state for External Gripping for the Collet Chuck.
Sorry Mtndew, I didn't mean to cut across your answer; I was still typing when you made your Post.
The parameter for OD or ID chucking needs to be changed depending on whether or not the collet nose is a "pullback" type which will have the parameter set to OD (or 0). If the collet nose is a true length (dead length or push type) then the parameter will be set to ID chucking (or 1).
This info is for an Okuma LNC8 with a 5020L control.
You should have a switch on the control panel for ID or OD chucking (you'll need the key for this). Just turn the key. On my older LC20 with 5000L control, it's on the lower right side next to the "CONTROL OFF" button. The 5000L-G control may be in a different spot.
On my lathe I had to reverse chucking direction to get the machine to clamp a collet properly.
On the OSP-5000 there's a key lock on the panel, indicating direction. Some older Okuma lathes have a two way valve near the pressure adjuster.