I'd like some opinions on if this type installation would meet the NEC:

Short version: When can shielded cables be ran in a suspended ceiling and not be in a raceway? Two types of cables, one with 120VDC for small motors and other is 24VDC for sensors, & encoders.

Long version:
Have a large custom control panel (120VAC max) and some test stands w/small DC motors, encoders, and sensors. All are in a lab/testing room. We need to run shielded cables between the control panel and test stands. Conduits (1 for low voltage & 1 for 120VDC) will extend up into a suspended ceiling and end. In the ceiling the cables are to be supported by the metal joists, and ty-rapped together.

Two questions spring to mind, is this a fire rated ceiling and is this a plenum for return air?

Are these cables a chapter 3 wiring method?

Not so much as would they need to be run in a raceway but what is the required wiring method. I doubt any would have to be run in raceway if the correct wiring is used.

Even with raceway you will have to determine whether these circuits are CL1, 2 or 3 and proceed from there. If any are CL1 you may not be able to use the wire you have even with raceway.

-Hal