Lufft SHM31 User Manual

Communication in Modbus mode
Snow depth sensor SHM 31, V2.1 55
18
17
Maximum snow
height difference
Maximum accepted snow height
difference between two
measurements [mm]
Range: -20000 … +20000
1
19
18
Laser operating
mode
Not yet implemented
Range: 0
1
20
19
Laser measurement
interval
Laser mesurement interval [msec]
Range 1000 … 60000
Values less than 5000ms are not
recommended!
1
11.
3.2. 0x04 Read Input Registers function
The input registers contain the measured values of the SHM 31-UMB and related status
information.
The measured values are mapped to the 16-bit registers by scaling (0 to max. 65530 for values
without a leading sign, -32762 to 32762 for values with a leading sign).
The values 65535 (0xffff) or 32767 are used to display faulty or unavailable measured values. A
more precise specification of the error can be determined from the status registers (see below).
The assignment of the measured values to the register addresses (0 – 119) was chosen so that
the user can read out the usual data with as few register block retrievals as possible (ideally only
one retrieval).
The following blocks were therefore formed:
• Status information
• Standard data set in metric units
• Standard data set in US units
• Distances
• Temperatures in metric units
• Temperatures in US units
• Angle
• Logical and normalised values
• Service channels
The table below lists the input registers with the scaling factors and the information as to whether
the read register value is to be interpreted as signed (S) or unsigned (U)
A scaling factor of 10 means that the register value must be divided by 10 to obtain a value with
a resolution of one decimal place.
Reg.
No.
Reg.
Adr.
Measurement value
Description
Factor
Signed /
unsigned
Status Information
1
0
Device Identification
High Byte: Device subtype
Low Byte: Software version
1
U
2
1
Device status
lower 16bit of the device status
1
U
3
2
Device-Status
upper 16bit of the device status
1
U
4
3
Status block heating
0 = Heating off
1 = Heating on
1
U
5
4
Status window heating
0 = Heating off
1 = Heating on
1
U
6
5
Status block temperature
UMB status code (see chapter 9.3.5)
1
U
7
6
Status ambient temperature
UMB status code (see chapter 9.3.5)
1
U
8
7
Status laser temperature
UMB status code (see chapter 9.3.5)
1
U
9
8
Status tilt angle
UMB status code (see chapter 9.3.5)
1
U
10
9
Status snow height
UMB status code (see chapter 9.3.5)
1
U
11
10
Status distance
UMB status code (see chapter 9.3.5)
1
U
12
11
Status normalized signal
UMB status code (see chapter 9.3.5)
1
U
13
12
reserved
14
13
reserved

Lufft SHM31 Specifications

General

Brand	Lufft
Model	SHM31
Category	Accessories
Language	English