Level measurement Uni-Probe LB 490

The universal field device for various applications

Uni-Probe LB 490 is used for non-contact measurement of levels and limit values. The compact field probe combines detector and evaluation in one device. The level gauge is inexpensive, reliable and accurate and comes with very low source activity.
The level measuring system Uni-Probe LB 490 has interfaces for HART, Profibus PA and Foundation Fieldbus.

Even if the level measurement LB 490 is used in Profibus or Fieldbus systems, it is always possible to switch to HART communication if required. The separate 4-20mA current output can alternatively be used as a signal output (e.g. for a remote display).

The robust field probe for high demands - your advantages at a glance:

  • Inexpensive and solid system for standard applications
  • Compact field device with integrated evaluation unit
  • Communication via HART, Foundation Fieldbus or Profibus PA
    (switchable from bus to HART)
  • Communication can be switched over from Bus to HART at any time
  • High operational safety, FMEDA with SFF 96%
  • Many digital and analogue outputs and inputs make the Uni-Probe universally usable

SuperSENS for extreme wall thicknesses

SuperSENS detectorLarge containers with extreme wall thicknesses require very high activities. When using the SuperSENS, the source activities can be significantly reduced.
If you already have measurements with point detectors and you are faced with the decision to replace the now weak sources, replacement with a SuperSENS can avoid a replacement of the source, as this will significantly increase the lifetime of the sources.

TowerSENS offers unlimited measuring range

Do you have large measuring ranges? No problem! The Uni-Probe TowerSENS is available in lengths up to 8 m. This saves you the cost-intensive use of multiple detectors that are connected to a multi-detector system. Installation and commissioning is simplified, since no other devices must be linked via interfaces. Ultimately, the risk of failure is reduced because the TowerSENS only requires electronics for up to 8 m. If the measuring range exceeds 8 m, additional TowerSENS can be connected to each other




LB 490
Detector operating data 
Power supply100 ... 240 VAC, ±10%, 50 ... 60 Hz, 15 VA
24 VDC (18 ... 32 VDC), 15 W; 24 VAC +10%/-15%, 50 ... 60 Hz, 15 VA

Cable connections

4 cable entries, 3/4 inch, NPT, closed with blind plug                 Option: metric adapters and cable glands upon request

maximum cable length

3300 m (120 Ω), 1600 m (250 Ω), 800 m (500 Ω)

Wire cross-section

0.5 ... 1.5 mm2

Housing materialStainless steel ISO 1.4301 / AISI 304
Water coolingOption, max. 6 bar


up to 8 detectors

 Scintillator Size   Weight   Weight with
Ø x length [mm]  [kg]        cooling systems[kg]  Collimator

CrystalSENS (point detectors)

50 x 50 (NaI/Tl)        22.5      24                              Standard

(rod detectors)

50 x 500 (polymer)   14        18.5                            Option
50 x 1000 (polymer) 17        25                               Option
50 x 1500 (polymer) 19        30.5                            Option
50 x 2000 (polymer) 21        36                               Option

basic module basic module
extension module

50 x 1000 (polymer) 20        27                                -
50 x 2000 (polymer) 26        41                                -
50 x 2000 (polymer) 17        32                                -
up to 3 extension modules

SuperSENS150 x 150 (polymer) 52        62                               Standard

Ambient temperature
Operation and storage

-40 ... +60 °C (-40 ... +140 °F) for NaI/Tl and/or
-40 °C ... +55 °C (-40 ... +131 °F) for polymer
Observe possible temp. restrictions for Ex-protection!
for 100...240 VAC version, operation only up to max. 50 °C

Temperature stability

≤0,002%/ °C (-20 ... +50 °C) for CrystalSENS and/or
≤0,01 %/ °C (-20 ... +50 °C) for UniSENS

Detector certificates & tests 

IP protection

IP65 / IP66 + Nema 4X

Explosion protection

II 2 GD EEx d IIB T5 IP66 T80 °C                         -40 ... +80 °C
II 2 GD EEx d IIC T6 IP66 T80  °C                        -40 ... +60 °C
(...+50°C for LB 490 TowerSENS and SuperSENS)
II 2 GD EEx d [ia] IIC T6 IP66 T80 °C                   -20 ... +50 °C

FM/Canada (FM/CSA):
Class I Division 1 Group A, B, C, D
Class II Division 1 Group E, F, G                           -40 ... + 50°C

Other certificatesNepsi, IECEx, Kosha, CCOE, others upon request
Signal inputs and outputs 
Signal outputHART 4 ... 20 mA potential-free, active or passive                            
max. impedance: 500 Ω (active)                                                    Voltage supply: 12 V ... 24 V (passive)

max. impedance at 12 V: 250 Ω and/or 24 V: 500 Ω (passive)

Option: intrinsically safe HART current output 4 ... 20 mA, potential-free, passive

Voltage supply: 12 ... 30 V, voltage drop <3.5 V, 20 m signal cable (blue), pre-assembled

Exi IIB: Lo=14.78 mH; Co=679 nF / Exi IIC: Lo=2.18 mH; Co=84 nF
Bus output - Option

Bus interface: Profibus PA or Foundation Fieldbus                            
Bus powered, typical 13 mA with 2xAI function blocks               
Option: intrinsically safe Bus interface, 20 m signal cable (blue), 
Approval according to ATEX and FISCO

Digital inputsDig In 1: Hold input, Dig In 2: Empty adjustment
Digital outputs1 relay (SPDT) for collective fault message
3 relays (SPDT) alternatively for: Hold signal, min. / max. alarm, detector temperature, radiation interference detection

Permissible load at ohmic load: max. 5 A at 250 VAC or 30 VDC

InterfacesRS 232 for software update

Data backup

in non-volatile memory


For HART, Foundation Fieldbus and Profibus
X-ray interference protection (XIP)
Event log
Continuously monitored current output


Application Report
Format Size
Continuous Level measurement for cement clinker coolers en PDF 754.12 KB
Level Measurement of coke drum level en PDF 694.69 KB
Format Size
Level Measurement Russian language en PDF 2.3 MB
Level Measurement Brochure en PDF 4.85 MB
Product Data Sheet LB 490 en PDF 244.23 KB
Whitepaper Radiometric Measurements Accurarcy, repeatability and errors en PDF 739.65 KB
Format Size
ATEX LB 490-TS, LB 491 SuperSENS en PDF 1.89 MB
CCOE LB 490-TS, LB 491 SuperSENS en PDF 243.11 KB
CCOE Zertifikat LB 49x en PDF 243.11 KB
CSA Zertifikat LB 49x en PDF 383.09 KB
FM LB 490-TS, LB 491 SuperSENS en PDF 244.5 KB
Uni-Probe ATEX Certificat LB49x en PDF 1.63 MB
Uni-Probe FM Certificat LB49x en PDF 63.96 KB
Operation Manual
Format Size
LB 490 Uni-Probe en PDF 31.77 MB
Product Information
Format Size
Level & Density Measurement for -50°C (-58°F) de, en PDF 2.26 MB
Uni-Probe User Interfaces en PPT 511 KB
Project Questionnaire
Format Size
Density en PDF 90.32 KB
Level en PDF 105.49 KB
Level Switch en PDF 109.14 KB
Software Tool
Format Size
LB 490 & LB 491 DTM for HART de, en ZIP 18.78 MB
LB 490 device description for Foundation Fieldbus with capability file de, en ZIP 79.65 KB
LB 490 device description for HART for Siemens Simatic PDM Version 6.0 de, en RAR 41.2 KB
LB 490 device description for HART-communicator de, en ZIP 76.06 KB
LB 490 device description for Profibus PA with GSD file de, en ZIP 95.33 KB
Technical Information
Format Size
LB 490 Uni-Probe de, en PDF 2.86 MB
LB 490 Tower-Sens de, en PDF 9.4 MB