Does the sun affect the measurement result?

No, LTL-XL has a built-in Stray Light Compensation effectively ensuring that ambient light from the sun or other light sources does not affect the accuracy of the measurement.

How long time does it take to measure?

To measure RL or Qd takes about 1 sec., to measure both parameters takes about 3 sec.

Can LTL-XL measure luminous flux (lumens)?

No, it is not possible to measure luminous flux.

Can I change the fuses if blown?

Yes you can, please see the attached instruction, LTL-XL, Fuses.

Click here

Can I upgrade my current LTL-XL with a High Power battery?

Yes you can. Please contact DELTA for a quotation. A High Powser battery will double the number of measurements to 2.000 per charge on a fresh battery.


How fast does the battery charge?

The standard battery will fully charge within 1½ hour, the High Power battery will fully charge within 3-3½ hour.

How many measurements can I take with a fully charged battery?

Depends on how the instrument is used; the use of LCD backlight, sound, GPS, printer and the measurements schedule all influence the achievable number of measurements. A fully charged and fresh standard battery will be able to make around 1.000 measurements, the High Power battery around 2.000 measurements.

When do we know that the battery should be replaced?

A fully charged and fresh standard battery will normally make around 1.000 measurements and a High Power battery around 2.000 measurements. If the number of measurements on a fully charged battery falls much below this number, it is time to replace it.

How long does a battery last before it needs to be replaced?

This depends on use pattern as mentioned above. It not used on a daily basis DELTA generally recommends keeping the battery fully charged maximising the life time, which is normally several years.

Can I change the battery myself?

Yes you can, please see the attached instruction, LTL-XL, Battery.

Click here


Can I calibrate the LTL-XL myself?

Yes you can by using the calibration unit that comes with the instrument. Please see the attached instruction,  LTL-XL, Calibration.

Click here

How often does the calibration standard need to be re-calibrated?

If kept dry in storage and taken well care of when used (no dirt, no scratches on the calibration block surface) it can last several years without needing re-calibration. DELTA, however, recommends to have a re-calibration or replacement of the calibration block done every two years to make sure that the calibration of the instruments is correct.

Is there an alternative to sending the calibration unit for re-calibration?

Yes, you can decide to purchase a new calibration unit from DELTA for your instrument, see our price list for details.  

How do I know that the calibration block needs re-calibration or needs to be changed?

When the calibration block is scratched, dirty (and cannot be properly cleaned) or otherwise damaged, it is time to replace it.

Does the retroreflectometer itself need to be re-calibrated?

The instrument comes calibrated from the factory. Unless the instrument has been damaged after e.g. being dropped or run over by a vehicle the instrument itself does not need re-calibration.

Instrument service

How often does the LTL-XL need to be serviced?

LTL-XL is a very robust instrument which can stand daily use without need for service. If you should have an accident with the instruments (being dropped, being hit hard and alike) DELTA recommends servicing the instrument. If you want to be sure that the instruments work correctly at all times you may consider an instrument service at DELTA at regular intervals. If the instrument is used every day DELTA recommends these intervals being once a year, if used less often a service every 2-3 years will do.

How do I know if/when the instrument needs service?

If the instrument doesn\’t work at all, if the instrument status informs you that it has detected problems (constant errors and/or warnings) or the measurement are obviously wrong, the instrument needs urgent service.

This is a unique website which will require a more modern browser to work! Please upgrade today!