Delta RetroSign GRX-1 User Manual page 64

The measurement field center indicators, on the sides and bottom of the GRX instrument, indicate
where the lens is positioned (see picture below). Use these indicators as guidance to ensure you are
placing the GRX correctly.
Sign conditions
The retroreflectivity of a sign changes when the sheeting becomes wet. RetroSign GRX can perform
measurements on wet or dewy sign surfaces but readings are not comparable with readings taken on
dry signs.
Because of the direction sensitive optical properties of certain micro prismatic sheeting types, it is
important to position the RetroSign GRX correctly and hold it vertically in order to obtain correct
readings as seen by the driver of a vehicle.
When checking correct positioning of direction sensitive micro prismatic sheeting types measure the
road traffic sign with the GRX in vertical and horizontal positions.
Battery condition
The instrument monitors the battery power level. The battery icon in the upper-right corner of the
display shows the battery power level:
Remember to charge the battery when it is low on power.
Note: The instrument automatically turns off when the battery is depleted.
Rechargeable batteries have a limited number of charge cycles and may eventually need to be
replaced.
See also 'Battery' in Section 2 – General Information.
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RetroSign GRX User Manual / December 2017 DELTA