Description: An EDM is incorporated into the instrument. In all versions, the distance can be determined by using a visible red laser beam which emerges coaxially from the telescope objective. Depending on the model, there are up to two EDM modes:
• Prism measurements
• Non-Prism measurements
Non-prism measurements
• When a distance measurement is triggered, the EDM measures to the object which is in the beam path at that moment. If a temporary obstruction, for example a passing vehicle, heavy rain, fog or snow is between the instrument and the point to be measured, the EDM may measure to the obstruction.
• Be sure that the laser beam is not reflected by anything close to the line of sight, for example highly reflective objects.
• Avoid interrupting the measuring beam while taking Non-Prism measurements or measurements using reflective foils.
• Do not measure with two instruments to the same target simultaneously.
Prism measurements
• Measurements to strongly reflecting targets such as traffic lights in Prism mode without a prism should be avoided. The measured distances may be wrong or inaccurate.
• When a distance measurement is triggered, the EDM measures to the object which is in the beam path at that moment. If for example people, cars, animals, or swaying branches cross the laser beam while a measurement is being taken, a fraction of the laser beam is reflected from these objects and may lead to incorrect distance values.
• Measurements to prisms are only critical if an object crosses the measuring beam at a distance of 0 to 30 m and the distance to be measured is more than 300 m.
• In practice, because the measuring time is very short, the user can always find a way of avoiding unwanted objects from interfering in the beam path.
Red laser to reflector tape
• The visible red laser beam can also be used to measure to reflective foils. To guarantee the accuracy the red laser beam must be perpendicular to the reflector tape and it must be well adjusted.
• Make sure the additive constant belongs to the selected target (reflector).