LH-20 高性能投入式液位测量传感器

Special features
Slender design
Adjustable turndown (option)
Resistant against the harshest environmental conditions
Reliable and secure by double-sealed design
Titanium case for especially high resistance (option)

Description

For the most demanding measurement tasks

The model LH-20 submersible pressure transmitter has been designed for the most demanding of level measurement tasks. A slender design, highest accuracies, low temperature errors and an adjustable measuring range ensure the suitability of the LH-20 for all submerged level measurements.
The model LH-20 submersible pressure transmitter can adapt to countless applications and measuring media through a large number of features and options. Depending on the requirements, this level probe is available with, amongst other things, a titanium case, PUR/PE/FEP cable, 0.1 % accuracy, HART?, scaleability or parallel temperature output signal.
For operation in hazardous environments, the model LH-20 submersible pressure transmitter is also available in an intrinsically safe version. For potable and fresh water applications, a potable water conformant product variant is possible in accordance with KTW and ACS.

Hermetically sealed, robust and durable
The model LH-20 submersible pressure transmitter has been engineered for use in the harshest environments. Through a double, redundant sealing concept, it is permanently hermetically sealed. A robust design from stainless steel or titanium, with a spring-reinforced cable seal, ensures a long service life, even under the big mechanical loads of installation and continuous use.
Designs with the highest media resistance using FEP cable and titanium cases, along with the integrated lightning protection, guarantee the longevity of the submersible pressure transmitter even under the most adverse environmental influences in aggressive media, in both indoor and outdoor use.

?Measuring ranges


Output signals

Output signal
Standard 4 ... 20 mA
Option 4 ... 20 mA and HART? signal, additional Pt100 measurement signal

Load in Ω
4 ... 20 mA:≤ (power supply - 8 V) / 0.022 A
4 ... 20 mA and HART? signal: ≤ (power supply - 9.6 V) / 0.022 A

Voltage supply

Power supply
The power supply depends on the selected output signal.
4 ... 20 mA: DC 8 ... 36 V
4 ... 20 mA and HART? signal: DC 9.6 ... 36 V

When being operated in Ex areas, the submersible pressure transmitter must be powered via an Ex isolated barrier.
For Ex isolated barrier see "Accessories"

Additional Pt100 measuring element
The HART? version has an additional Pt100 measuring element for measuring the temperature of the medium.

Specifications:
Pt100 per DIN EN 60751
Measuring range -50 ... +100 °C
Resolution of 1 °K

Reference conditions

Temperature
15 ... 25 °C

Atmospheric pressure
860 ... 1,060 mbar

Humidity
45 ... 75 % relative

Mounting position
Calibrated in vertical mounting position with pressure
connection facing downwards.

Accuracy data

Non-linearity at reference conditions
Non-linearity
Standard ≤ ±0.2 % of span
Option ≤ ±0.1 % of span

By setting a turndown of greater than 5:1, the non-linearity is decreased.

Determined using the limit point method in accordance to IEC 60770

Temperature error of the zero point in the temperature range 0 ... 80 °C

at non-linearity ≤ 0.2 % of span
- Standard, without turndown ≤ 0.15 % of span/10 K
- Turndown ≤ 5:1 ≤ 0.20 % of span/10 K
- Turndown > 5:1 ≤ 0.25 % of span/10 K
at non-linearity ≤ ± 0.1 % of span
- Standard, without turndown ≤ 0.05 % of span/10 K
- Turndown ≤ 5:1 ≤ 0.10 % of span/10 K
- Turndown > 5:1 ≤ 0.15 % of span/10 K

Long-term drift
≤ 0.1 % of span/year

Settling time (0 ... 63 %)
Depending on the output signal the following settling times
apply:
4 ... 20 mA: 100 ms
4 ... 20 mA, HART? signal: 200 ms

Scalability (turndown)
The HART? version enables turndown to be set.
It is recommended that turndown is not set to over 5:1, since the accuracy can decrease dependant on the scaling.

Operating conditions

Ingress protection (per IEC 60529)
IP 68

Vibration resistance (per IEC 60068-2-6)
4 g (at 5 ... 100 Hz)

Lightning protection
Nominal discharge current ≥ 5 kA, response time < 25 ns

Explosion protection (optional)
The model LH-20 submersible pressure transmitter is available with the following Ex approvals, which can be ordered separately.

Approval
ATEX II 1G, 2G Ex ia IIC T6
IECEx ia IIC T6

Temperatures
for use without explosion protection

The permissible temperature ranges are dependent on the cable material used:
- Medium
- PE cable: - 40 ... +60 °C
- PUR cable: - 40 ... +80 °C
- FEP cable: - 40 ... +80 °C
- Ambient
- PE cable: - 40 ... +60 °C
- PUR cable: - 40 ... +85 °C
- FEP cable: - 40 ... +85 °C
- Storage
- PE cable: - 40 ... +80 °C
- PUR cable: - 40 ... +80 °C
- FEP cable: - 40 ... +80 °C

for use as Category 1G equipment
- Ambient
- Temperature class T6: - 20 ... +50 °C
- Temperature class T1 ... T5: - 20 ... +60 °C

for use as Category 2G equipment

- Ambient
- Temperature class T6: -40 ... +66 °C
- Temperature class T1 ... T5: -40 ... +80 °C

Maximum tensile force on the cable
1,200 N

Weight
Submersible pressure transmitter: approx. 370 g
Cable: approx. 100 g/m
Additional weight (accessories): approx. 350 g

Process connections
The model LH-20 is available in two process connection variants:

Process connection
Standard M14 x 1 with

Option Flush measuring cell

Electrical connections

Reverse polarity protection
U+ vs. UOvervoltage

Overvoltage protection
see lightning protection under "Operating conditions"

Cable lengths
Cable length to customer requirements, freely selectable

Connection diagrams


Approvals, directives and certificates

Approvals and certificates
On request, the submersible pressure transmitter can be supplied with the following approvals and certificates:
Available approvals
ATEX (explosion protection in accordance with ATEX)
IECEx (explosion protection in accordance with IECEx)
GL (Germanischer Lloyd)

Available certificates
Drinking water declaration of conformity in accordance with KTW and ACS
Test certificate 1)
1) The test certificate documents the product-specific instrument specifications and include a detailed listing of the individual measured values of the acceptance test.

Outputsignal 4 ... 20 mA and HART? signal:
EMC directive 2004/108/EC, EN 61326 emission (group 1, class A) and interference immunity (industrial application)

ATEX 94/9/EG (option)

Materials (wetted)

Case
Standard Stainless steel 316L
Option Titan

Cable material
Standard PUR
Option 1 PE
Option 2 FEP

Sealing material 1)
Standard FKM
Option EPDM
1) The model LH-20 is double sealed behind the sensor.