Brand: JUMO

JUMO Wtrans Receiver Universal Wireless Receiver

Name: JUMO Wtrans Receiver Universal Receiver 902931 | Seven Star LLC
Brand: JUMO
SKU: 902931

Description

DIN-rail receiver that turns wireless measured values into signals

The JUMO Wtrans receiver (type 902931, receiver T01) is the universal receiver for JUMO wireless measuring probes. It receives measured values from the Wtrans transmitters on the industrial radio frequency of 868.4 MHz or 915 MHz and processes up to 16 measured values per receiver. No cabling to the sensor is needed.

In the receiver the values are converted, displayed on a two-line LCD and provided as linear current or voltage signals of 0(4) to 20 mA or 0 to 10 V, as well as over the RS485 interface with Modbus protocol. All outputs are galvanically isolated. The Modbus link allows connection to higher-ranking systems such as the JUMO SVS3000 visualization software or a Modbus-master JUMO LOGOSCREEN recorder.

Operation is by keypad and LCD or by a setup program, where filter constants, offset, alarms and drag indicators with minimum and maximum memory can be set for each channel.

The receiver for each channel offers separate filter constants, offsets, alarms and drag indicators, so the same unit can serve temperature probes, pressure transmitters and humidity or CO2 probes with different needs. Units for temperature, pressure, potentiometer and voltage are configurable.

Technical specifications

Parameter	Specification
Type	902931/10 (4 analog outputs) and 902931/30 (2 analog outputs and 2 relays)
Channels	Up to 16 measured values per receiver
Radio frequency	868.4 MHz (Europe) or 915 MHz (America, Australia, Canada, New Zealand); ten configurable frequencies at 915 MHz
Range	Up to 300 m in open air with antenna holder and 3 m antenna cable; about 40 % less with the antenna on the receiver
Analog outputs	0/4 to 20 mA (burden up to 500 Ohm) or 0 to 10 V (load at least 10 kOhm); accuracy +/-0.1 %
Relay outputs	2 N/O relays on /30, up to 3 A at AC 230 V resistive; contact life 150,000 operations at 3 A
Interfaces	RS485 with Modbus; USB/TTL connector on the front for the setup program
Isolation	Analog outputs isolated from each other and from interfaces; 50 V isolation
Supply	AC 110 to 240 V +10/-15 % or AC/DC 20 to 30 V, 48 to 63 Hz; 12 VA
Ambient temperature	-20 to +50 °C without condensation, also with close mounting
Housing	DIN-rail case 35 x 7.5 mm; IP20; approx. 200 g
Compatible transmitters	Wtrans T (902930), Wtrans B (707060), Wtrans p (402060), Wtrans E01 (902928)

Order code and accessories

The order code is 902931 / basic type / version / frequency / supply / extra code. Basic type /10 has four analog outputs, /30 has two analog outputs and two relays. Version 8 uses default settings and version 9 a customer-specific configuration. Frequency 10 is 868.4 MHz and 20 is 915 MHz, which cannot be combined with the AC/DC 20 to 30 V supply.

The delivery includes the receiver, a lambda/4 antenna for the chosen frequency and an operating manual. Accessories include the setup program with or without OnlineChart, extra antennas, an antenna holder for wall mounting, and 10 m or 20 m antenna cables with waterproof line.

Check that the transmitter software version is supported by the receiver software version, because newer transmitters such as the Wtrans E01 need a later receiver software.

Output monitoring is built in. If the signal drops below range, a 4 to 20 mA output falls to 3.8 mA and then jumps to the configured signal, and above range it rises to 20.5 mA. For probe break or alarms the output can be set to positive signaling above 21 mA or negative signaling below 3.6 mA, so a PLC can detect a failed wireless channel.

The setting time after switch-on or reset is up to 5 seconds, and the setting time for temperature changes depends on the transmission interval set in the transmitter. Calibration conditions are AC 230 V or DC 24 V at 22 °C.

The delivered lambda/4 antenna has a 50 Ohm impedance and a maximum temperature of 125 °C, and it can be screwed directly on the receiver or mounted externally on the wall holder for a longer range.

Applications

The receiver is the single collection point for a wireless measuring system in a hall, a storage area or a test site. It converts the radio values into the analog or Modbus signals that a PLC, recorder or visualization system can read.

Alarms can be set for each channel, and the relay version can switch a lamp or horn. Mount the antenna outside a metal control cabinet where possible, because metal enclosures strongly reduce radio reception.

Relay contacts are rated up to 3 A at AC 230 V resistive load with 150,000 operations, and the relay N/O contact can be configured as an N/C contact. Relay-to-relay test voltage is AC 2300 V and relay to analog outputs AC 3700 V with reinforced insulation.

Setup uses a connector at the front for a PC interface with a USB/TTL converter. The setup program with OnlineChart can record the received values on a PC, and the screw terminals at different levels accept conductors up to 2.5 mm2.

Documents and quotation

For engineering details, open the attached PDF (JUMO Wtrans receiver data sheet 902931 (EN, 10 pages)). When you are ready to buy, submit the order code and project requirements through the request form, and our team will confirm what can be supplied and when. Browse the category Temperature Instrumentation for alternatives.

Datasheets & Documents

Datasheet JUMO Wtrans receiver data sheet 902931 (EN, 10 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.