Delta LTL2000S User Manual

LTL2000S / SQ RETROREFLECTOMETER

Manual

DELTA ⋅ Venlighedsvej 4 ⋅ DK-2970 Hørsholm ⋅ Denmark ⋅ Tel. [phone] ⋅ Fax [phone] ⋅ www.delta.dk

DISCLAIMER

The information contained in this document is subject to change

without notice.

DELTA LIGHT & OPTICS MAKES NO
WARRANTY OF ANY KIND WITH RE­GARD TO THIS MATERIAL, INCLUD­ING, BUT NOT LIMITED TO, THE IM­PLIED WARRANTIES OF MERCHAN­TABILITY AND FITNESS FOR A PAR­TICULAR PURPOSE. DELTA LIGHT &
OPTICS SHALL NOT BE LIABLE FOR
ERRORS CONTAINED HEREIN OR FOR
INCIDENTAL OR CONSEQUENTIAL
DAMAGES IN CONNECTION WITH THE
FURNISHING, PERFORMANCE OR USE
OF THIS MATERIAL.

Rev. 080104

SW ver: 1.6

DELTA LTL2000S(Q) Retroreflectometer

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INDEX

SECTION 1................................................................................................................................ 1

INTRODUCTION............................................................................................................................. 1

Introduction ................................................................................................................................................... 1

LTL2000S(Q) features .................................................................................................................................. 2

Getting started ............................................................................................................................................... 3

Buttons........................................................................................................................................................... 3

Measuring...................................................................................................................................................... 3

Warning and Errors ....................................................................................................................................... 3

Calibration - LTL2000S ................................................................................................................................ 6

Calibration - LTL2000SQ ............................................................................................................................. 8

SECTION 2.............................................................................................................................. 11

GENERAL INFORMATION ........................................................................................................ 11

Rl Measurement........................................................................................................................................... 11

Qd Measurement ......................................................................................................................................... 15

Instrument function ..................................................................................................................................... 17

Factory calibration....................................................................................................................................... 17

Notes on error sources................................................................................................................................. 17

SECTION 3.............................................................................................................................. 19

KEYBOARD, DISPLAY AND FUNCTIONS.............................................................................. 19

Keyboard Layout......................................................................................................................................... 19

Keyboard functions ..................................................................................................................................... 19

Clear log data............................................................................................................................................... 20

Measurement id ........................................................................................................................................... 20

Mean Calculation......................................................................................................................................... 21

Menu system................................................................................................................................................ 21

SECTION 4.............................................................................................................................. 25

MAINTENANCE ............................................................................................................................ 25

General care................................................................................................................................................. 25

Protection window....................................................................................................................................... 25

Battery ......................................................................................................................................................... 25

Fuses............................................................................................................................................................ 26

Lamp............................................................................................................................................................ 26

Calibration unit............................................................................................................................................ 26

Light trap ..................................................................................................................................................... 27

Printer .......................................................................................................................................................... 28

APPENDIX A .......................................................................................................................... 29

COMMUNICATION FACILITIES.............................................................................................. 29

RS-232C specification................................................................................................................................. 29

Data protocol ............................................................................................................................................... 31

Command format......................................................................................................................................... 32

Command set............................................................................................................................................... 33

APPENDIX B .......................................................................................................................... 36

Status code interpretation .............................................................................................................. 36

APPENDIX C .......................................................................................................................... 37

Print outs.......................................................................................................................................... 37

Result Printout............................................................................................................................................. 37

Rl Calibration Printout ................................................................................................................................ 37

Qd Calibration Printout ............................................................................................................................... 37

Log Printout................................................................................................................................................. 38

Status Printout ............................................................................................................................................. 39

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APPENDIX C .......................................................................................................................... 40

SPECIFICATION........................................................................................................................... 40

General Characteristics Rl........................................................................................................................... 40

General Characteristics Qd.......................................................................................................................... 40

Electrical Characteristics ............................................................................................................................. 41

Environmental Characteristics..................................................................................................................... 41

Mechanical Characteristics.......................................................................................................................... 41

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SECTION 1

INTRODUCTION

Introduction

This manual covers both LTL2000S and LTL2000SQ. Some functions will only be available
on LTL2000SQ and will be printed in blue colour.

The LTL2000S is a portable field instrument, intended for measuring the reflection properties
of road markings “Rl” as seen in the vehicle headlight illumination.

To measure the Rl properties (coefficient of retro reflected luminance) the road is illuminated
at an angle of 1.24 deg. and the reflected light is measured at an angle of 2.29 deg.

The LTL2000SQ is intended for measuring both “Rl” and the lightness of road surfaces and
road markings “Qd” as seen under daylight conditions or with stationary lighting.

To measure the Qd properties (the luminance coefficient under diffuse illumination) the road
is illuminated with a diffuse source and the reflected light is again measured at an angle of

2.29 deg.

An observation angle of 2.29 deg corresponds to an observational distance of 30 metre, thus
relevant for a motorist viewing situation under normal driving conditions.

Rl and Qd is important factors in the ON-SITE quality control of road markings.

The operation of the instrument is very simple and requires a minimum of instruction. An er­ror message or warning is given in case of unreliable or erroneous measurement.

The LTL2000S(Q) measures the Rl and Qd values according to international agreements. Re­sults are presented in plain English on a LCD display. The built-in printer and non-volatile
memory provides on site registration of measurements with corresponding date and time.

DELTA LTL2000S(Q) Retroreflectometer 1

LTL2000S

LTL2000SQ

Serial communication on RS232 port gives extended command, calibration, diagnostics and
data dump facilities.

The LTL2000S(Q) is powered by a rechargeable lead acid battery, giving several hours of
measurement capacity. A mains powered battery charger is supplied as standard.

LTL2000S(Q) features

• Portable self-contained instrument

• Measurement in full daylight

• Automatic stray light compensation and error diagnostics

• Dry and wet surfaces

• Plane, textured & profiled markings

• Measurement geometry and illumination corresponding to realistic viewing

condition in traffic

• Direct digital read out

• Automatic mean calculation

• Built-in printer

• Real time clock

• Automatic data storage in internal non-volatile memory

• RS232 serial communication for operation, data dump, extended control and di-

agnostics

• Automatic programmable power off function

• Easy calibration procedure

• Calibration unit

• Carrying case

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Getting started

F

Buttons

Meas ure Men u Ent er Hom e OF

Calibr ate Print Sc roll d own Sc roll up ON

Measuring

Turn the instrument on by pressing and holding the button until the LCD shows:

Retrometer
LTL2000SQ v1.6

Retrometer
2004-01-08 10:55

Calibrate the instrument if necessary, see Calibration page 6.

Place the instrument on the road marking. Press the key.
The measurement will start instantly. Duration approx. 3 sec. depending on measurement
mode (approx. 5. sec when measuring both Rl and Qd).

When finished the measured Rl (and Qd) values, the date/time or measurement id and status
info is displayed. The information’s are automatically transferred to the internal data log for
later readout to the serial communication port or printout.

The instrument can automatically calculate and display the mean (average) value of 2 or more
measurements, if the Mean Calc function is ON. See Menu system.

Warning and Errors

Warning and errors are indicated in the lower right positions in the second line of the display:

* = Everything O.K.
W = Warning Measurement O.K. but warning condition detected.
L = Warning Measurement O.K. but high stray light detected.
E = Error Measurement unreliable.

If the error indicator is different from * then press to print–out the status from the last

measurement or press one or more times to select Status Display and then use to

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scroll through the status list to see the possible cause of the problem. For further description
on the error messages see Status Display page 19. Alternatively or select the menu Print
Status to print a complete instrument status.

Note:

Wet night measurement considerations:

Making wet night measurements on warm road surfaces requires special considerations.
Due to the large thermal mass of the road, the road temperature is not influenced very much
by the water.
Pouring water on the hot road surface will generate steam. When placing the instrument on
the wet road steam will condense in the instrument also on the front window.
Condense on the optical surfaces will result in measure error!

Tests has shown that steam especially condensate on the outside surface of the front window.
When removing the instrument from the road, the dew will evaporate quickly and the instru­ment will again take correct readings.

It is recommended to make the "wet measurements" at the lowest possible road temperature!

When battery voltage becomes low a warning (W) is shown in the lower
right corner of display. It is still possible to take measurements but when
the voltage drops too low, readings can be erroneous.

If in doubt whether the readings are correct make a control measurement
on the calibration unit.

Print Result:

Press to print the result from last calibration or measurement to the printer.

Menu:

Press this key to enter the menu section. Press again to scroll through the menu structure.

From the Menu it is possible to control most of the instrument settings such as mean calcula­tion, data log functions, real time setup and automatic turn off timer, see Menu system page

21.

The measuring mode (Qd, Rl or both) is set using this key.

The sequence of the menu functions changes depending on what mode the instrument is in at
the moment. Example: when taking measurements with the mean calculation on the first func­tion shown will be the Clear Mean function.

Home:

Press this key to terminate a menu or calibration and display the latest measurement result, if

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the Mean calculation function is enabled and there is more than 1 measurement in the calcula­tion then the number of measurements is shown first.

Scroll Keys:

In normal mode the key activates the Clear Top Log function, in menu mode it is used to
scroll through the menu functions and to increment shown values.
In normal mode the key activates the Edit Sequence Id function, in menu mode it is used to
scroll through menu functions and to decrement shown values.

For more information about the keyboard buttons please see page 19.

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Calibration - LTL2000S

A calibration should always be carried out before starting a new series of measurements.

Calibration is done by placing the calibration unit underneath the instrument between the
rails. The easiest way to place the unit is to tilt the instrument backwards.

Figure 1. How to tilt the instrument.

The calibration units are fitted with guidance pins on the outside. The pins mounted in the
middle of the longitudinal direction of the unit shall fit in the notch in the rails.

The instrument automatically compensates for zero signal, leakage and other possible error
sources, and calculates the calibration factor. This process is fully automatic and if the cali­bration routine is followed precisely the retroreflectometer will now measure “true” Rl.

Rl Calibration

Rl calibration step 1 to 8 actually consists of two calibrations: a “zero calibration” and a
“normal calibration”. The zero calibration is done on the calibrator light trap and the normal
calibration on the ceramics. It is important to turn the Rl calibration unit the right way during
the calibration sequence. See figure 2 (page 9).

Press the key to enter calibration mode and follow the instructions in the display.

Note:

Step 1 + 4: See figure 2 on how to place the calibration unit.
Step 2: The message will be shown for a couple of seconds.
Step 3: The message will be shown briefly.
Step 5: The message will be shown for a couple of seconds.
Step 6: Edit the Rl Normal value according to the value printed on the calibration unit.

Step 7: Accept the shown normal value.

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The display shows:
Step 1 Step 2 Step 3 Step 4 Step 5

Mount Light Trap

when Ready

Zeroing
Please Wait

Zero OK
Zero: 0.05%

Mount Rl Normal

when ready

Calibrating
Please Wait

Step 6 Step 7 Step 8

Rl Normal 150

= OK to Edit Wait

Rl Normal 150

= when OK

Calibration Done
Remove Normal

To verify the calibration do a Rl measurement on the normal before removing the normal in
step 8.

To document the calibration press the key to print.

In the example above the Rl function is now calibrated to a Rl value of 150.
If an error is detected during the calibration procedure then the display will indicate this.

Note:

• Avoid calibration in direct sunlight

• Store the reference calibration unit in a dry and clean environment.

DELTA LTL2000S(Q) Retroreflectometer 7

Calibration - LTL2000SQ

A calibration should always be carried out before starting a new series of measurements.

The LTL2000SQ is supplied with two calibration units. One for Rl and one for Qd.
The order of R1 / Qd calibration is not critical. Qd calibration can be done before the Rl cali­bration and reverse. The Rl / Qd calibration can also be performed individually.

The Qd calibration only consist of one calibration (no zero calibration is needed).

Calibration is done by placing the calibration unit underneath the instrument between the
rails. The easiest way to place the unit is to tilt the instrument backwards, see picture page 6.
The calibration units are fitted with guidance pins on the outside. The pins mounted in the
middle of the longitudinal direction of the unit shall fit in the notch in the rails, see figure 2
page 9.

The instrument automatically compensates for zero signal, leakage and other possible error
sources, and calculates the calibration factor. This process is fully automatic and if the cali­bration routine is followed precisely the retroreflectometer will now measure “true” Rl / Qd.

Calibrate:
Press the key to enter calibration mode.

If only Rl or Qd mode is enabled then this mode is the only one shown. In the example both
Qd and Rl are enabled.
The display will show:

Use or key to activate the wanted calibration sequence.

Qd Calibration:
Follow the instructions in the display.

Note:

Step 1: The vertical black plate on the calibration unit shall face forward (see figure 2 page 9).
Step 2: The message will be shown for a couple of seconds.
Step 3: Edit the Qd Normal value according to the value printed on the calibration unit.

The display shows:

Step 1 Step 2

Step3 Step 4 Step 5

Qd Normal: 200

= OK to Edit

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Calibration

= Qd = Rl

Mount Qd Normal

when Ready

Qd Normal: 215

= when OK

Calibrating
Please Wait

Calibration Done
Remove Normal

If the key is pressed the calibration result is printed.

In the example above the Qd function is now calibrated to a Qd value of 215. If an error is
detected during the calibration procedure then the display will indicate this.

Rl Calibration:

See Rl calibration page 6.

Rail

Guidance pin
placed in notch

Zero calibration for
the Rl calibration (step

1 in the detailed de­scription page 5).

Rl calibration (step 4
in the detailed de­scription page 5)

Qd calibration (step 1
in the detailed de­scription page 6.)

The normal must be placed
with this side up for the
different calibrations.

Guidance pins

Figure 2. How to place the calibration normals.

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Remember:

 Recharge battery when possible. Never leave battery discharged for longer periods

of time.

 Keep protection window, light trap and calibration unit clean.
 LTL2000S(Q) is an optical precision instrument, handle with care.
 Store in clean and dry environment

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