This version provides two Prox/Accel channels and two Velomitor channels with internal barriers. It is intended for a mixed measurement schedule, so the four field loops must be assigned to that exact two-plus-two population.

Its first two channels serve Prox/Accel inputs and its other two serve Velomitor inputs, while the -03 version is dedicated to four Velomitor channels. This channel-role difference is the main reason the variants should not be substituted.

The published internal-barrier information associates it with supported 3500/42 and 3500/70 arrangements. The front monitor, rear I/O position and mixed sensor schedule need to form one approved configuration rather than being selected independently.

The internal barriers depend on the specified intrinsic-safety grounding arrangement to operate within the approved system design. Earthing is therefore part of the system configuration and should be included in the cabinet and documentation review.

Its mixed population can combine two shaft-relative or acceleration inputs with two casing-velocity inputs. That allows a project to serve different measurement types through one barrier I/O variant when the associated monitor arrangement supports them.

The RFQ should identify the exact -02 suffix, associated front monitor, rack position, two Prox/Accel loops, two Velomitor loops and intrinsic-safety arrangement. This makes the required mixed-channel function explicit and avoids a four-Velomitor substitution.