Emerson 404B Quick Start Manual page 17

June 2018
if a pulse has been detected. Excessive movement or vibration can cause an
intermittent or false operation due to a loss of alignment to the targeted
area.
Note
If you are attaching the magnetic mount to equipment that is not grounded,
there is a possibility of producing a ground loop (electrical) problem that will
cause the 404B Infrared Phototach to become unstable.
1. Place the reflective tape provided with the package on the shaft of the
equipment to be analyzed. If the surface of the shaft is shiny or of a
reflective nature, the 404B Infrared Phototach will capture false readings.
Paint the shaft on the area surrounding the attached tape with a darker,
non-reflective color.
2. Position the 404B Infrared Phototach perpendicular to the reflective tape.
Figure 4-2:
If a pulse is not detected, change the angle of the 404B Infrared Phototach to
10 to 15 degrees off a line perpendicular to the reflective tape.
If the 404B Infrared Phototach signals are erratic, you may need to adjust the
gain on the 404B Infrared Phototach:
1. Remove the screw holding the clear plastic cover on the rear of the yellow
tach head.
2. Ensure that the L.O.\D.O. control is in the full counterclockwise position.
MHM-97921, Rev 0
404B Infrared Phototach properly positioned for use
Quick Start Guide
17