Brand: JUMO

JUMO safetyM STB/STW Ex Safety Temperature Limiter, Type 701155

Name: JUMO safetyM STB/STW Ex Temperature Limiter | Seven Star LLC
Brand: JUMO
SKU: safetyM STB/STW Ex

Description

DIN-rail safety temperature limiter with intrinsically safe inputs for Ex areas

The JUMO safetyM STB/STW Ex (type 701155) is a safety temperature limiter or monitor that is installed outside the Ex area but accepts probes inside it. Its two universal inputs are intrinsically safe [Ex ia], so the relevant probes connect directly and no separate barrier is needed. The data sheet states approvals to DIN EN 14597, SIL 3, PL e and ATEX, with DNV approval for versions with extra code 062.

The 1oo2D architecture compares two independent channels and a diagnostic processor, which is how the device detects its own faults. The device is also certified as an ignition source monitoring device (iPL 2) to DIN EN 50495 and DIN EN ISO 80079-37, so it can monitor equipment in gas or dust atmospheres. A backlit 96 x 64 pixel display with plain-text menus, four keys and a USB setup interface handle configuration.

The first stage of the logic compares both analog inputs and flags probe short circuits by difference monitoring, so a failed probe drives the alarm relay to its safe state rather than staying silent. Thermocouples, RTDs and 4 to 20 mA signals can be mixed on the two channels as the order code allows.

Technical specifications

Parameter	Specification
Type	701155; STB/STW per DIN EN 14597 with SIL, PL and iPL approval (extra code 059 always present)
Inputs	Two universal analog inputs, [Ex ia]; single probe (1) or double probe (2)
RTD inputs	Pt100 / Pt1000 -200 to +850 °C; max. line resistance 15 Ohm (2-wire), 30 Ohm (3-wire); 50 ppm/K
Thermocouples	L, J, U, T, K, N, S, R, B, D and C types; e.g. K -200 to +1372 °C, B 0 to 1820 °C, D 0 to 2495 °C, C 0 to 2315 °C; accuracy 0.4 %
Current input	4 to 20 mA, voltage drop below 2 V, 0.2 %
Sampling / fault tolerance time	210 ms; error tolerance time up to 5 s
Outputs	Alarm relay (changeover, 3.15 AT fuse cut-out) AC 230 V, 3 A; pre-alarm relay KV (changeover) AC 250 V, 3 A; analog output 0/4 to 20 mA or 0/2 to 10 V
Digital input	Potential-free contact for unlocking, keyboard lock or level inhibit
Supply	AC 110 to 240 V +10/-15 %, 48 to 63 Hz, or AC/DC 20 to 30 V; max. 12 W
Display	LCD, black/white with backlight, 96 x 64 pixels; LEDs OK, K1, K2, KV, KD
Approvals as printed	DIN CERTCO STB/STW1228; TUV Nord SIL 2/3 and PL e (SEBS-A.102606/16-2); ATEX i (TUV 11 ATEX 556139 X) and ATEX e/t (SEV 17 ATEX 0161 X); IECEx i and e/t; UKCA with extra code 085; DNV with extra code 062
Ignition protection level	044 (blue terminals, intrinsically safe) or 045 (black terminals)
Ambient / storage	0 to +55 °C / -30 to +70 °C; altitude up to 2000 m
Housing	Polycarbonate, UL 94 V0; 35 mm DIN rail (EN 60715); screw terminals up to 2.5 mm2; IP20; approx. 230 g

Order code and approval options

The order code runs: version (8 default or 9 customer-specific), language (01 German, 02 English, 03 French), switching behavior (0251 to 0254 for monitor or limiter, maximum or minimum alarm), measurement input (for example 2001 for 2 x Pt100 in three-wire circuit), supply, ignition protection level (044 or 045) and extra codes 059, 062 and 085. An example from the data sheet is 701155/8-01-0253-2001-23-044-005/059.

Accessories are a multilingual setup program, a USB cable and an external unlocking button. The data sheet notes that the device itself must be installed outside the Ex area, so plan the cabinet location and the probe cable route accordingly.

The display and control elements are clearly separated: green OK lamp for the valid range, red K1 and K2 for alarm, yellow KV for the pre-alarm and yellow KD when the diagnostic processor has switched off. The keys can only be reached when the transparent hood is folded up, and an external unlocking button RT is available as an accessory.

Applications in hazardous plants

Use it where a heater, reactor jacket, dryer or heat-transfer loop must be shut down safely and the probe sits in a classified zone, for example in chemical, petrochemical and gas-processing areas. The two-channel design suits functional-safety loops that require SIL or PL e evidence; the certificates listed in the data sheet should be checked against the project specification and the applicable local rules.

Choose the 044 version with blue terminals for [Ex ia] probe circuits and follow the usual installation rules for intrinsically safe circuits. The Reset step after an alarm is deliberate: the operator must acknowledge a limiter trip with the keys behind the transparent hood.

The terminal temperature is monitored as well: if it leaves the -10 to +80 °C window the device shows a terminal-temperature error and moves the output to a safe state, and the message can only be acknowledged after the temperature is back in range. Plan cabinet ventilation so the terminals stay inside that range.

Documents and quotation

For engineering details, open the attached PDF (JUMO safetyM STB/STW Ex data sheet 701155 V5.00 (EN)). 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 safetyM STB/STW Ex data sheet 701155 V5.00 (EN) 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.