It is the correct variant when the rear I/O position must serve four Velomitor channels with internal intrinsic-safety barriers in a supported 3500/42 or 3500/70 arrangement. The four-channel sensor population is the key selection boundary.

No. This version is configured for four Velomitor inputs, while the mixed variant divides its channels between two Prox/Accel and two Velomitor inputs. The two parts may look similar but support different field-sensor populations.

The internal-barrier documentation associates this rear I/O variant with supported 3500/42 and 3500/70 monitoring arrangements. The front monitor type, rear slot position and field sensor schedule must all agree with the four-Velomitor configuration.

They integrate the intrinsic-safety barrier function into the rear I/O assembly for the four Velomitor channels. The complete approved installation still depends on the associated monitor arrangement, earthing provisions and project intrinsic-safety design.

A common rear-I/O, earthing, monitor-interface or shared-power condition is more likely than four independent sensor failures at the same moment. The diagnostic path should begin with the items common to the module before individual field loops are disturbed.

The decisive wording is four Velomitor channels with internal barriers, together with the exact -03 suffix. Including the associated front monitor and sensor schedule gives the buyer a clear configuration reference rather than relying on a similar module photograph.