Delta RetroSign GRX-1, User Manual

Page: 63 / 80

RetroSign GRX User Manual / December 2017
63
DELTA
How to limit errors
The RetroSign GRX automatically gives a message/warning signal if there is something wrong with a
measurement. To avoid measurement errors and poor quality of data a number of precautions can be
taken.
Before measuring
The RetroSign GRX is factory calibrated. However, to avoid measurement errors it is recommended
always to begin important measurements sessions with a calibration of the instrument. Carry out
minimum one daily calibration after checking the optical surfaces are clean, free of dust, and
undamaged. Dust and smear on the optical surfaces might influence the measured values
considerably.
It is very important to keep the instrument front lens and the white calibration reference clean
and undamaged to obtain correct calibrations and thereby correct measurement results.
See also Section 5 - Maintenance .
Instrument orientation
To obtain reliable inspection results the front of the RetroSign GRX must be in close contact with the
sign surface when taking measurements.
However, RetroSign GRX can conduct measurements without contact to the sign surface. If you do
have to perform inspections like this please consult your appointed dealer or DELTA, for instruction in
your specific situation.