The ornamental design for a readerdevice for a diagnostic system, as shown and described.
FIG. 1 is a top, front, and right side perspective view of a first embodiment of a reader device for a diagnostic system;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side view thereof, the left side being a mirror image;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a top, front, and right side perspective view of a second embodiment of a reader device for a diagnostic system;
FIG. 8 is a front view thereof;
FIG. 9 is a rear view thereof;
FIG. 10 is a right side view thereof, the left side being a mirror image.
FIG. 11 is a top plan view thereof; and,
FIG. 12 is a bottom plan view thereof.
The broken lines depict portions of the reader device for a diagnostic system that form no part of the claimed design; the broken lines form no part of the claimed design.