Installation 
26  Rev. D7 Jul 2017  Marathon MM 
6 Installation 
6.1 Mechanical Installation 
After all preparations are complete, you can install the sensor. How and where you anchor the sensor 
depends on the type of surface and the type of bracket you are using. You can mount the sensor through 
a hole, on a bracket of your own design, or on the available bracket accessory. 
6.1.1 Distance to Object 
The  desired  spot  size  on  the  target  will  determine  the  maximum  measurement  distance  and  the 
necessary focus length of the optical module. To avoid erroneous readings the target spot  size must 
contain the entire field of view of the sensor. Consequently, the sensor must be positioned so the field 
of view is the same as or smaller than the desired target size. For a list indicating the available focus 
models and their parameters, see section 3.2 Optical Specifications, page 16. 
 
Figure 3: Proper Sensor Placement 
6.1.2 Variable Focus 
The optional variable focus allows adjustment of the focus length of the sensor optics. Using sensors 
with this feature requires that the correct focal distance be set on the sensor. To determine the correct 
focal distance for the sensor, measure the distance in millimeters from the face of the sensor to the target. 
Set the focal distance to be equal to the measured distance. It is possible to set the focal distance either 
on the control panel of the sensor or through the DataTemp Multidrop Software. 
The factory default focal distance is 600 mm (23.6 in.).