Lufft SHM31 User Manual

Communication in SDI-12 mode
Snow depth sensor SHM 31, V2.1 47
Measurand
UMB-Channel
Min
Max
Unit
Buffer ‘0’
Run time
4007
0
9999999
s
snow depth (cur)
612
-629.9
629.9
mm
snow flag (cur)
700
0
1
code
fogging flag (cur)
710
0
1
code
signal normalized
800
0
255
-
Buffer ‘1’
distance
650
-19.7
826.8
mm
SHM31 error
4100
0
255
code
Table 9: SDI-12, additional values (M1 / C2: Flags) configured in US units. The fog flag is not calculated at present.
10.
8. Device identification telegram
The device identification query is answered with the following telegram (example of SDI-12 device
address ‘0’:
0I!
013Lufft.deSHM31xnnn
x: Metric / US units ( m = metric, u = US ), nnn: Software version
i
.e. for an SHM 31-UMB set to US units:
0I!
013Lufft.deSHM31u010
10.9. Telegram verification
The command verification aV! is used to identify the device’s status information. The query is
answered with
a0002<CR><LF>
i.e. two measured values are available in the buffers.
The measured values, transferred in buffer 0, contain the status information of the device’s
measuring channels.
The channels’ status data is combined to form ‘pseudo-measurements’, where each digit
represents a status. See below for the states’ coding. Positions listed as ‘reserved’ in the table are
allocated to ‘0’.
Buffer ‘0’
Status group 1: +nnnn
Block temperature status, ambient
temperature status, laser temperature status,
tilt angle status
Status group 2: +nnnn
x/y/z angle status, snow depth status,
calibration distance status, flags status

Lufft SHM31 Specifications

General

Brand	Lufft
Model	SHM31
Category	Accessories
Language	English