Brand: JUMO

JUMO ecoTRANS Lf 01/02 DIN-Rail Conductivity Transmitter and Switching Device, Type 202731

Name: JUMO ecoTRANS Lf 01/02 Conductivity Transmitter
Brand: JUMO
SKU: ecoTRANS Lf 01/02

Description

A DIN-rail conductivity transmitter with either a 4-20 mA output or a teach-in relay

The JUMO ecoTRANS Lf 01/02 (type 202731) is a microprocessor transmitter and switching device for electrolytic conductivity sensors that use the two-electrode principle. It is built for general water engineering: freshwater monitoring and treatment, reverse osmosis and ion exchanger plants, condensate monitoring and cooling-water checks. The Lf 01 offers a freely configurable, galvanically isolated analog output and is positioned as an economical universal transmitter. The Lf 02 carries a changeover relay, and its teach-in connector can set the switching point automatically from the actual measured value. Both mount on a 35 mm DIN rail and have three-way isolation between supply, input and output.

Technical specifications

Parameter	Specification
Variants	202731/01 with analog output; 202731/02 with relay changeover contact; no conversion between the two
Conductivity input	Two-electrode cells with cell constants 0.01, 0.1, 1.0 or 10 per cm; constant adjustable 20 to 500 %
Measuring ranges	0 to 5 uS/cm up to 0 to 200 mS/cm depending on cell constant (for example 0.1 per cm: 0 to 200 or 1000 uS/cm; 1 per cm: 0 to 2 or 20 mS/cm; 10 per cm: 0 to 100 or 200 mS/cm)
Deviation from characteristic	Plus or minus 1.0 % of range for 5 and 20 uS/cm ranges; plus or minus 2.0 % for all others
Temperature input	Pt100 or Pt1000, 2- or 3-wire, -10 to +250 degC; NTC/PTC as customised characteristic up to 4500 ohm; reference temperature 10 to 40 degC (factory 25 degC)
Temperature coefficient	0 to 5.5 % per degC, automatic determination or manual entry
Analog output (Lf 01)	0(2) to 10 V (load 3 kohm or more) or 0(4) to 20 mA (load 400 ohm or less), also inverted; scaling span at least 10 % of range; deviation plus or minus 0.015 mA or 5 mV
Relay (Lf 02)	Changeover contact 4 A at 250 V AC or 4 A at 24 V DC resistive; over 100,000 operations at rated load
Relay functions	Limit with hysteresis, pulse function, pull-in and drop-out delay, teach-in switching point
Supply	20 to 30 V DC, ripple under 5 %, 2 W, reverse-polarity protection, SELV or PELV circuits
Sampling / resolution	500 ms (two measurements per second); 14-bit A/D converter
Monitoring	Out-of-range of conductivity and temperature, probe short circuit or break; outputs adopt a configured state
Ambient / storage temperature	-10 to +60 degC; -20 to +75 degC; humidity up to 93 % without condensation
Housing	Polycarbonate DIN-rail case, IP20, approx. 110 g; screw terminals to 2.5 mm2
Safety / EMC	EN 61010, overvoltage category II, pollution degree 2; EN 61326, emission class B
Order code	202731/01-015/000 (code 2: 01 or 02; code 3: 015 = 0 to 2 mS/cm, 016 = 0 to 20 mS/cm; code 4: 000 or 024 with PC setup software)
Stock versions	202731/01-015/000 part no. 00421026; /01-015/024 00421035; /02-016/000 00421032 (3 working days)

Setup, calibration and stock presets

The Lf 01 is operated only through the PC setup program, while the Lf 02 switching point can be set either in the program or with the teach-in connector. Setup covers calibration of the cell constant, either by manual entry or automatic calibration of the relative cell constant, calibration of the temperature coefficient, zero-point correction, lead-resistance compensation for ranges above 20 mS/cm (0 to 99.99 ohm) and a temperature offset of plus or minus 20 degC. A calibration timer reminds the operator when calibration is due, and the manual mode lets the output be simulated for dry-run commissioning of a plant without a measuring cell.

All stock versions can be freely reprogrammed; they differ only in preset range and cell constant. Common presets are automatic temperature compensation with Pt100, a 4 to 20 mA output on the Lf 01 or a switching point at maximum range on the Lf 02, and a temperature coefficient of 2.2 % per degC. The PC setup software is part no. 00432577 and the USB/TTL interface cable with two adapters is 00456352.

Compatible sensors and accessories

The datasheet lists the conductive sensors 202922 (BlackLine CR), 202923 (ecoLine CR-PVC), 202924 (tecLine CR) and 202925 (tecLine CR-GT), cables and plugs from data sheet 202990, and calibration simulators from 202711. Other items available from stock are a conductivity simulator (00300478), a process connection for it (00082901) and a DIN-rail switching power supply PS5R-A-24 (00374661). Sensors connect through a DIN 43650 connector, a fixed cable or an M12 connector with white, brown, yellow and green conductors for electrodes and temperature compensation.

For related published items see the dTRANS CR 02 and AQUIS 500 CR, and browse liquid analytical systems. An enquiry should name the sensor type and cell constant, the conductivity range, whether an analog output or a relay is needed, the temperature probe and the supply voltage.

Documents and quotation

Hosted for reference is the official JUMO data sheet 202731, version 4.00 dated 2024-12-09, seven pages in English, with technical data, connection diagrams, order code, stock versions and accessories. Seven Star LLC is an independent supplier in Muscat; send the order code and we will prepare a quotation.

Datasheets & Documents

Datasheet JUMO ecoTRANS Lf 01/02 data sheet 202731 V4.00 (EN, 7 pages) Download

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About brand

JUMO is the German maker of temperature sensors, process controllers, pressure transmitters and liquid analysis instruments. Moritz Kurt Juchheim founded it in Fulda in 1948 as M. K. Juchheim KG, making glass thermometers with six employees. The name JUMO comes from the founder's name. It is still a family company headquartered in Fulda, and the parent company has been called JUMO GmbH & Co. KG since 2003.

Seven Star LLC is an independent supplier in Muscat. We list JUMO RTD and thermocouple probes, thermowells, transmitters, controllers, recorders and water analysis instruments, and supply them to process plants, OEMs, HVAC contractors and water utilities in Oman and the GCC by type number.

JUMO company profile

Established	1948, Fulda, Germany, by Moritz Kurt Juchheim
First products	Glass and contact thermometers; platinum glass sensors from 1966
Ownership	Family-owned; renamed JUMO GmbH & Co. KG in 2003
Product families	RTD and thermocouple probes, thermowells, temperature and pressure transmitters, controllers and thermostats, safety temperature limiters, paperless recorders, liquid analysis and flow and level instruments

Milestones

1948: Moritz Kurt Juchheim founds M. K. Juchheim KG in Fulda, making glass thermometers with six employees.
1966: Platinum glass temperature sensors are added.
2003: The parent company is renamed JUMO GmbH & Co. KG.

JUMO products we list

Family	Models	Typical use
RTD and thermocouple probes	902020, 902030, 902050, 902120, 902006 2xPt100, PROCESStemp, mineral-insulated RTD, 901020 thermocouple, 901210, 902810 hygienic, 902550 surface, 902520 HVAC, MarineTemp	Temperature measurement in pipes, vessels, machines, HVAC and food plants
Thermowells and inserts	909710 thermowells, 909740 measuring inserts	Protecting sensors and replacing them without opening the process
Temperature transmitters	dTRANS T01, T03, T04, T05, T06 SIL, T07 HART, T09, T1000 IO-Link, DELOS T switch	Converting sensor signals to 4-20 mA, HART or IO-Link
Pressure and level	dTRANS p20, p30, p31 hygienic, p33 Ex, p02 DELTA, MIDAS S05, MIDAS DP10, DELOS S02, MAERA S25, NESOS R20	Pressure in process, hydraulic and OEM systems; tank and well level
Controllers, limiters and recorders	DICON touch, IMAGO 500, dTRON 316, iTRON, cTRON, diraTRON 104, eTRON T, safetyM STB/STW, safetyM TB/TW, LOGOSCREEN 601, mTRON T	Furnace, oven and process control, over-temperature protection and recording
Liquid analysis and flow	AQUIS touch S, AQUIS touch P, AQUIS 500 pH, AQUIS 500 CR, dTRANS pH 02, pH electrode, digiLine DO, ecoLine NTU, flowTRANS MAG H20, flowTRANS US W01	pH, conductivity, oxygen and turbidity in water treatment; liquid flow

Choosing a temperature sensor starts with the range and accuracy. A Pt100 RTD is accurate and stable from about -200 to 600 °C and is the usual choice in process plants. A thermocouple (type K or J, for example) covers much higher temperatures and responds faster but is less accurate. The wiring also matters: a 3-wire or 4-wire Pt100 connection cancels the resistance of the cable, while a 2-wire connection adds an error that grows with cable length. That is why a head-mounted transmitter is often fitted close to the sensor.

Where JUMO products are used

In Oman and the GCC, JUMO sensors and controllers are used in oil and gas and chemical plants, food and beverage production, plastics and metal heat treatment, HVAC and district cooling, water and wastewater treatment, swimming pools and marine applications.

Ordering JUMO products: what we need

Send the JUMO type number and the full order code from the label (for example 902020/10-...). For probes, add the sensor type (Pt100, Pt1000, type K or J), the number of wires, the insertion length and diameter, and the process connection. For controllers, add the input, outputs and supply voltage.

Facts checked against JUMO's company history, October 2026.

Browse JUMO products by category: Temperature Instrumentation, Pressure Instrumentation, Liquid Analysis Sensors, Controllers & Data Acquisition, Level Transmitter.