Keller LEX1 Specifications

LEX 1

Digital precision manometer

Features

• High precision of up to 0,01 %FS

• Insulated piezoresistive pressure sensor encapsulated in an oil-lled metal housing

• RS485 bus interface for communication with up to 128 devices

• Battery-operated with up to 2000 hours of battery life

• Can be used with external power supply

• License-free KELLER software available to download

• Intrinsically safe, explosion-proof version LEX 1 Ei available

Functions

• Wide range of units of pressure to choose from

• Zero point calibration via button

• Automatic shutdown

• Min/max display

• User-dened units of pressure can be congured

• Digital calibration (zero point, end point)

Typical applications

• Calibration

• Laboratory use

• Industrial applications

Accuracy

± 0,05 %FS

Total error band

± 0,05 %FS

Pressure ranges

from 0...30 mbar to 0...1000 bar

LEX-1 with piezoresistive measuring cell LEX-1 with capacitive measuring cell

KELLER AG für Druckmesstechnik

CH-8404 Winterthur

[phone]
[e-mail]

KELLER Ges. für Druckmesstechnik mbH

DE-79798 Jestetten

[phone]
[e-mail]

KELLER America

Newport News, Virginia

1 877 253 5537
[e-mail]

Edition 05/2019

Subject to alterations
Companies approved to ISO 9001

www.keller-druck.com

Page 2 of 6

LEX 1 – Specications

Standard pressure ranges

LEX 1 piezoresistive

Gauge pressure, PR

Absolute pressure, PAA

Absolute pressure, PA

Overload resistance

Display resolution

LEX 1 capacitive

Gauge pressure, PR

Differential pressure, PD

Overload resistance

Negative overload resistance

Display resolution

Key

Performance

-1…1 -1…3 -1…6 -1…10 -1…16 -1…30 bar rel.

0…2 0…4 0…7 0…11 0…17 0…31 0…61 0…101 0…161 bar abs.

8 8 20 20 90 90 300 300 600 600 800 1100 1100 bar

0,1 0,1 1 1 1 1 1 10 10 10 20 50 100 mbar

0…30 0…100 0…300

300 1000 1500 mbar

30 100 300 mbar

0,01 0,01 0,1 mbar

PR Gauge pressure Zero at atmospheric pressure
PAA Absolute pressure Zero at 0 mbar abs. (vacuum)
PA Absolute pressure Zero at 1000 mbar abs.
PD Differential

0…300 0…400 0…700 0…1000 bar

mbar

mbar diff.

LEX 1 piezoresistive

Accuracy @ RT (20…25 °C) ≤ ± 0,05 %FS

Nonlinearity (BFSL), pressure hysteresis, non-repeatability,

zero point, amplication

Total error band (0...50 °C) ≤ ± 0,05 %FS Max. deviation within the specied pressure and temperature range

Long-term stability

Degree of dependency on location ≤ ± 1,5 mbar

≤ 0,1 %FS > 1 bar, per year under reference conditions, yearly recalibration recommended

≤ 1,0 mbar ≤ 1 bar, per year under reference conditions, yearly recalibration recommended

Calibrated in vertical installation position
with pressure connection facing downwards

Accuracy of temperature measurement ± 1 °C typ.

Pressure range reserve ± 10%

Vacuum endurance ≤ 0,2 bar abs. Of operation ≤ 0,2 bar abs. upon request

LEX 1 capacitive

Accuracy @ RT (20…25 °C) ≤ ± 0,1 %FS

Nonlinearity (BFSL), pressure hysteresis, non-repeatability,

zero point, amplication

Total error band (0...50 °C) ≤ ± 0,2 %FS Max. deviation within the specied pressure and temperature range

Long-term stability ≤ 0,1 %FS Per year under reference conditions, yearly recalibration recommended

Long-term stability 30 mbar range ≤ 0.1 mbar Per year under reference conditions, yearly recalibration recommended

Degree of dependency on location none

Line pressure dependency (PD versions) ≤ ± 0,005 %FS / bar

Accuracy of temperature measurement ± 1 °C typ.

Pressure range reserve ± 10%

Line pressure ≤ 2 bar

KELLER AG für Druckmesstechnik
CH-8404 Winterthur

[phone]
[e-mail]

KELLER Ges. für Druckmesstechnik mbH

DE-79798 Jestetten

[phone]
[e-mail]

KELLER America

Newport News, Virginia

1 877 253 5537
[e-mail]

Edition 05/2019

Subject to alterations
Companies approved to ISO 9001

www.keller-druck.com

Page 3 of 6

LEX 1 – Specications

Performance

Optional for LEX 1 piezoresistive

Precision @ RT (20…25 °C)

Accuracy @ RT ≤ ± 0,01 %FS

For PA/PAA ≥ 10 bar, except for ush versions.

Accuracy ± 0,05 %FS, with KELLER test report ex works (standard)

Keller uses pressure sources to calibrate its products that are at least four times more accurate than the product
to be tested. This enables us to produce products in our factory with an absolute accuracy of up to ± 0,05 %FS.

Precision ± 0,01 %FS / 0,025 %FS, with KELLER test report ex works

Additional measurement work and selection of a specic pressure transducer means that optimum repeatability

is guaranteed for selected pressure transmitters and digital manometers. Owing to the residual measurement

uncertainty of the pressure sources used at its factory, KELLER cannot provide any verication of measurement

accuracy at scales below ± 0,05 %FS for these ultra-precise devices. KELLER therefore uses the term "preci­sion" to denote the ability of a pressure transmitter or manometer to repeat measured values within a tolerance
of 0,01 %FS based on the pressure sources used at the factory.

Accuracy ± 0,01 %FS with DakkS (German accreditation body) certicate,

issued by an external accredited calibration laboratory

By calibrating the zero point and performing amplication via the digital interface, an accredited calibration

laboratory (ilac.org) can adapt ultra-precise KELLER products to their more accurate pressure sources and
record the results. External calibration to an accuracy of up to ± 0,01 %FS is performed in accordance with
the guidelines set out by the German Calibration Service (DKD) and is conducted under reference conditions
without any consideration of long-term effects.

≤ ± 0,01 %FS

≤ ± 0.025 %FS

Nonlinearity (BFSL), pressure hysteresis, non-repeatability,
with KELLER test report ex works

With DakkS (German accreditation body) certicate issued
by external calibration laboratory

Temperature ranges

Compensated temperature range 0…50 °C

Media temperature 0…50 °C

Ambient temperature 0…50 °C

Storage temperature -20…70 °C

Electrical data

Battery 3 V, type CR2430

Battery life approx. 2000 hours when used continuously

External power supply 8...28 VDC

Overvoltage protection and reverse polarity of
external power supply

RS485 voltage insulation -7...+12 VDC

GND case insulation > 10 MΩ @ 50 VDC

External interface RS485 half-duplex

Interface measuring rate 30 measurements per second

Electrical connection Fischer D 103 A054-130

CE conformity as per 2014/30/EU (EMC)

± 32 VDC

EN 61000-6-1 to -6-4
EN 61326-1 / EN 61326-2-3

LEX1 Ei only permitted for use in haz­ardous atmospheres when used with the
Renata CR2430

LEX 1 Ei devices must not be supplied
with power from an external source and
the RS485 interface must not be used in
the Ex zone. See operating instructions
for further information

KELLER AG für Druckmesstechnik
CH-8404 Winterthur

[phone]
[e-mail]

KELLER Ges. für Druckmesstechnik mbH

DE-79798 Jestetten

[phone]
[e-mail]

KELLER America

Newport News, Virginia

1 877 253 5537
[e-mail]

Edition 05/2019

Subject to alterations
Companies approved to ISO 9001

www.keller-druck.com

Page 4 of 6

LEX 1 – Specications

Display

Dimensions/appearance

Number of digits on LC display 2 rows with 5 digits each

Display mode Pressure + min/max or pressure + temperature

Measuring rate 2 measurements per second

Congurable units of pressure

Additional units of pressure 5 user-dened units can be congured

Width x height: 27,8 x 30,0 mm " see Dimensions & options

[bar], [mbar], [hPa], [kPa], [MPa], [PSI], [mH2O], [cmH2O], [inH2O], [ftH2O], [mmHg],
[inHg], [kp/cm2]

Mechanical data

Materials in contact with media

Component LEX 1 piezoresistive LEX 1 capacitive

Pressure connection Stainless steel AISI 316L Stainless steel AISI 316L

Pressure transducer separating diaphragm Stainless steel AISI 316L Aluminium oxide 96%, gold-plated

Pressure transducer seal (internal) FKM (Viton® type A) Nitrile

Pressure connection seal (external) FKM (Viton® type A) FKM (Viton® type A)

Other materials

Component LEX 1 piezoresistive LEX 1 capacitive

Display housing Faradex AS-1003 Faradex AS-1003

Oil lling pressure transducer Silicone oil None

Further details

Component LEX 1 piezoresistive LEX 1 capacitive

Pressure connection G1/4, see Dimensions & options

Diameter x height x depth (approx.) 76 x 118 x 55 mm 76 x 148 x 55 mm

Weight (approx.) 300 g 335 g

Protection IP65

Explosion protection LEX 1 Ei

Intrinsically safe version
in accordance with 2014/34/EU and IECEx

KELLER AG für Druckmesstechnik
CH-8404 Winterthur

[phone]
[e-mail]

PTB 05 ATEX 2012 X
IECEx PTB 13.0028 X
Zone 1: Ex II 2 G Ex ia IIC T6 Gb

KELLER Ges. für Druckmesstechnik mbH

DE-79798 Jestetten

[phone]
[e-mail]

Permitted max. ambient
temperature range -20…65 °C

KELLER America

Newport News, Virginia

1 877 253 5537
[e-mail]

Edition 05/2019

Subject to alterations
Companies approved to ISO 9001

www.keller-druck.com

Page 5 of 6

LEX 1 – Dimensions & options

J

E

2 : 1

G

2 : 1

J

G

2 : 1

J

Fischer Flanschdose

DEE 103 A054-130

Binder Flanschstecker

Serie 723

Stiftplatte
mPm-393

1

2

3

4

5

2

0

5

G1/2

1

4

1/4-18 NPT

1

5

2

0

2

0

5

1/4-18 NPT

1

5

2

0

2

0

5

2

0

2

0

5

6



1

5

3

7

°



43,5

1

4

1

6

G1/2

2

0

5

6



1

2

G1/4

G1/2

1

4

1/4-18 NPT

1

5

1/2-14 NPT

2

0

1

3

3

5



1

5

3

7

°

50,5





43,5

1

6

G1/2

2

0

5

6



G1/2

1

4

1/4-18 NPT

1

5

1/2-14 NPT

2

0

1

3

3

5



50,5





43,5

G1/2

2

0

5

6



1/4-18 NPT

1

5

1/2-14 NPT

2

0

1

3

3

5



G1/4

G1/2

2

0

5

6



1/2-14 NPT

2

0

1

3

3

5



G1/4

G1/2

2

0

5

6



1

3

3

5



G1/4

Display

Placement Display information

Width x height:
27,8 x 30,0 mm

Digit height:
8,4 pt. large
6,3 pt. small

External connection

Placement Connection Pin assignment

Fischer connector D 103 A054-130 Red Reference point

1 GND

1

5

2

4

3

2 n.c.

3 +Vcc

4 RS485 A

5 RS485 B

Available pressure connections

G1/4 (standard) G1/2 1/4 NPT 1/2 NPT G1/2 EN 837

0

2
1

G1/4

4
1

G1/2

5
1

1/4-18 NPT

0
2

1/2-14 NPT

G1/2 ush G3/4 ush 7/16-20 UNF Clamp DIN 32676 ush G1/4 EN 837

5
1



43,5

50,5



G1/2

G3/4

7/16-20 UNF-2A

3

7

°

Other pressure connections available upon request.

Other customer-specic options

• Other pressure and temperature ranges

• Parts that come into contact with media made from Hastelloy, Inconel or titanium

• Customer-specic front covers

• Integration of application-specic calculations

• Customer-specic rmware

• Detached pressure transducer

• Axial pressure connection

• Other sealing materials

• Other oil llings pressure transducer

2

5

G1/2

6



KELLER AG für Druckmesstechnik
CH-8404 Winterthur

[phone]
[e-mail]

KELLER Ges. für Druckmesstechnik mbH

DE-79798 Jestetten

[phone]
[e-mail]

KELLER America

Newport News, Virginia

1 877 253 5537
[e-mail]

Edition 05/2019

Subject to alterations
Companies approved to ISO 9001

www.keller-druck.com

Page 6 of 6

LEX 1 – Software & accessories

Swiss Made

«CCS30» software

Recording measured values

• Live visualisation

• Adjustable measuring and storage interval

• Export function

Conguration

• Call up of information (pressure and temperature

range, rmware version, serial number etc.)

«ManoCong» software

The ManoCong program is compatible with all

types of KELLER manometers and allows end cus-

tomers to congure the devices.

Range of functions

• Display of online measured values

• Conguring the wait period before automatic
shutdown

• Selecting standard pressure units

Interface

The LEX 1 manometer has a digital interface (RS485
half-duplex) which supports the KELLER bus proto­col. The pressure measurement rate via the inter­face is up to 30 x per second. Details of the commu­nication protocols can be found at www.keller-druck.
com. Documentation, a Dynamic Link Library (DLL)
and various programming examples are available to
integrate the communication protocol into your own
software.

• Activating/deactivating pressure units

• User-dened pressure units can be programmed

• Restoring to factory settings

• Calibrating the manometer

Interface converters

The connection to a computer is established via an
RS485-USB interface converter. Suitable converters

Software download

are available as accessories. To ensure smooth op­eration, we recommend the K-114 A converter with

www.keller-druck.com/software

the corresponding USB connector.

Scope of delivery

Plastic case CR2430 battery KELLER test report Operating instructions D/E/F

LEX 1

Aktueller Druckwert
Actual Pressure Value
Valeur de pression actuelle

Min.-/Max.-Druckwert
Min.-/Max. Pressure Value
Valeur de pression Min./Max.

ENTER
Min./Max.

SELECT

Druckanschluss
Pressure Connection
Raccord pression

Hochgenaues digitales Manometer

Highly Precise Digital Manometer

Manomètre Numérique de Haute Précision

Accessories

Interface converters Calibration certicate Rubber cover Carry case

K-114 A

• With Fischer plug (5-pin)

• Various adapter cables
available

K-114 BT A

• with Bluetooth interface
and integrated recharge­able battery

• Wireless connection via

Serial Port Prole (SPP)

• 15 V measuring device

supply from the converter’s

internal battery

Issued by the external
calibration laboratory of the
German accreditation body
DAkkS or the Swiss accredita­tion body SAS

For additional protection in
harsh environments

With belt loop

KELLER AG für Druckmesstechnik
CH-8404 Winterthur

[phone]
[e-mail]

KELLER Ges. für Druckmesstechnik mbH

DE-79798 Jestetten

[phone]
[e-mail]

KELLER America

Newport News, Virginia

1 877 253 5537
[e-mail]

Edition 05/2019

Subject to alterations
Companies approved to ISO 9001

www.keller-druck.com