The laser is switched off initially in software trigger mode. The laser is activated with the
Start measuring
SOPAS command or the
sMN LMCstartmeas
telegram (hexadecimal:
734D4E204C4D4373746172746D656173
). It is deactivated with the
Standby
command
or the
sMN LMCstandby
telegram (hexadecimal:
734D4E204C4D437374616E646279
).
This mode is designed for the use of telegrams for triggering measurement data output
and for setting up the device with the SOPAS ET parameterization software.
A third option for a digital trigger is to use input 1 and input 2 both individually and in
an OR link. These three trigger modes are intended for when the device is used with
one or more photoelectric sensors. Due to possible restrictions affecting the installation
position, the use of switch-on and switch-off delays is advisable in many cases.
NOTE
The laser is also switched off when logging in on the device via a terminal with the
sMN
SetAccessMode
telegram command (see the Listing Ranging sensors telegram,
no. 8014631).
Changes to the device are only taken into account with the
sMN Run
log-off command;
this also switches the laser back on.
3.5.5
Remission value
Remission is the ability of a material to reflect light. The remission value correlates with
the amount of laser light emitted by the LiDAR sensor which is reflected by an object
(see Lambert’s law).
Shiny surfaces have different remission values at the same distance with different
angles of impact. In the case of shiny surfaces, maximum remission is achieved when
the beam makes vertical impact.
Matt and dull surfaces have diffuse remission. Therefore, they exhibit similar relative
remission values with the same angle of impact regardless of the distance from the
zero point.
Table 3: Typical remission values of frequently used materials
Material
Typ. relative remission value
Rubber tires (vulcanized, black)
2%
Foam rubber (black)
2.4%
Photographic board (black, matte)
10%
Cardboard (gray)
20%
Wood (untreated fir, soiled)
40%
PVC (gray)
50%
Paper (white, matte)
80%
Plaster (white)
100%
Aluminum (black anodized)
110 … 150%
Steel (stainless, shiny)
120 … 150%
Steel (high gloss)
140 … 200%
3.5.6
Impact of object surfaces on the measurement
The received signal from a perfectly diffuse reflection from a white surface (diffuse
Lambertian reflector) corresponds to a remission of 100%. By this definition, surfaces
that reflect the light in bundles (reflecting surfaces, reflectors) have remissions of over
100%.
3
PRODUCT DESCRIPTION
18
O P E R A T I N G I N S T R U C T I O N S | LMS4000
8023198//2018-06-18 | SICK
Subject to change without notice