Lufft SHM31 User Manual

Service, maintenance and technical support
Snow depth sensor SHM 31, V2.1 63
13.
3. Faults
13.3.1. Possible indications of error on the snow depth sensor
Description of error
Cause and remedy
The device cannot be queried or is not
responding
• Check the supply voltage
• Check the cable
• Check the interface connection. If necessary,
use the RS232 interface to determin
e
w
hether the error is only with the RS
485
interface.
The device provides implausible values
• Check whether the assembly instructions
were followed when attaching the sensor
• Check the reference values; see the
‘Checking the signal quality’ section
13.3.2. Potential interferences that may affect correct functioning
- The snow depth sensor’s transmitting and receiving window is dirty.
A reflective surface / icy surface is reflecting most of the laser beam. This may also mean that the
l
aser beam is reflected back into the laser when the sensor is assembled vertically. This can also
lead to an error message.
- The target is ambiguous, e.g. due to a water column on the substrate
13.3.3. Error codes
The status codes for the SHM 31 snow depth sensor can be retrieved in the UMB channels 4100
and 4101. The status is also output in the UMB-ASCII 2.0 data telegram.
The codes are based on those of the SHM 30 snow depth sensor and have been specifically
expanded.
Error codes
Description
E15
Laser: Signal too weak; distance too short
E16
Laser: Signal too strong (mirror reflection effect)
E17
Laser: Background light level too strong
E18
Laser: Measurement disturbed (precipitation, movement, etc.)
E19
Laser switched off due to too many timeouts
E20
Laser communication error (unknown command)
E21
Laser communication error (interface)
E22
Laser communication error (invalid response)
E23
Laser temperature below -15°C
E24
Laser temperature above +50°C
E31
Hardware error; EEPROM checksum incorrect (sensor must be sent in for repair)
E32
Laser: Hardware error; EEPROM checksum incorrect
(sensor must be sent in for repair)
E51
Laser: APD power failure (scattered light or hardware error)
E52
Laser current too high; defective laser (sensor must be sent in for repair)
E53
Mathematics (division by 0)
E54
Laser: Hardware error (sensor must be sent in for repair)
E55
Hardware error (sensor must be sent in for repair)

Lufft SHM31 Specifications

General

Brand	Lufft
Model	SHM31
Category	Accessories
Language	English