Series-EX

Supported Applications

The Rotronic HygroFlex5-EX series consists of intrinsically safe humidity and temperature transmitters designed for fixed installation in explosive environments. The product overview identifies suitability for HVAC, food, pharmaceutical, printing, and paper industries where high measurement accuracy is required. These devices measure relative humidity and temperature while calculating psychrometric parameters such as dew point, enthalpy, and mixing ratio.

Operating Conditions & Performance

The series measures within a range of 0 to 100 %rh for humidity and -40...60 °C (T5) or -40...85 °C (T4) for temperature. Accuracy is specified as ±0.8 %rh at 23 °C for humidity and ±0.1 °C at 23 °C for temperature when using HC2-SM/IM/IE-EX probes with ROTRONIC HYGROMER® IN-1 sensors and Pt100 Class A elements.

Operating conditions vary by configuration: the electronics operate from -40...60 °C without a display, or -10...60 °C with an optional LCD. The measuring sensor supports ambient temperatures of -40...+85 °C depending on the temperature class (T4/T5). Start-up time is less than 60 s for cold start and less than 30 s for warm start, with a measurement interval configurable between 20...240 s.

The transmitter provides two analog current outputs of 4...20 mA in a two-wire circuit with galvanic isolation. The maximum load resistance is 500 Ohms, and the power supply requirement is 10...28 VDC. Current consumption is approximately 2x24 mA at start-up and 2x20 mA during operation.

Approvals & Certifications

The series holds Ex, IECEx, cPSUS, CE, UKCA, ATEX, EMC, and RoHS certifications. Specific hazardous location ratings include:

• Sensor (T5): II 1/2 G Ex ia IIC T5 Ga/Gb; II 1/2 D Ex ia IIIC T80°C Da/Db.
• Sensor (T4): II 1/2 G Ex ia IIC T4 Ga/Gb; II 1/2 D Ex ia IIIC T110°C Da/Db.
• Transmitter: II 2(1) G Ex eb mb [ia Ga] IIC T5 Gb; II 2(1) D Ex tb [ia Da] IIIC T80 °C Db.

Certification numbers include SEV 14 ATEX 0107, IECEx SEV 14.0002, and CML 22UEKX3190. North American identification covers Class I, Div 1/2 Groups ABCD T5...T4; Class II, Div 1/2 Groups EFG T80 °C...T110 °C.

Configuration Options

The HygroFlex5-EX series is available in wall-mounted (HF520-EX-W) and duct-mounted (HF520-EX-D) versions. The housing material is Aluminium (DIN EN 1706 EN AC-AlSi 12 (Fe)) with an IP66 enclosure rating.

Mounting & Dimensions

• Wall Version: 160 x 210 x 110 mm; Weight: 1030 g.
• Duct Version: 235 x 100 x 61 mm (depth/height/width); Weight: 1140 g.

Sensor & Probe Options

The series supports interchangeable stainless steel probes from the AirChip 3000 ATEX family. Standard non-ATEX sensors must not be used. Available probe types include:

• HC2-SM-EX: Short insertion length (15 mm diameter, 104 mm stem).
• HC2-IMxxx-EX: Cable probes with lengths of 2 m, 5 m, or 10 m; probe lengths of 125 mm or 285 mm.
• HC2-IExxx-EX: Screw-in probes with ½" G thread (metric) or ½" NPT thread (North American), available in cable lengths of 2 m, 5 m, and 10 m.

The wetted materials include stainless steel sheaths. A steel sinter filter (SP-FN15) is offered as a replacement part or accessory for protection against dust.

Outputs & Configuration

• Analog Outputs: Two freely selectable 4...20 mA outputs for relative humidity, temperature, or derived parameters (e.g., dew point).
• Display: Optional LCD without backlight; can show trend indicators and alarm symbols.
• Service Interface: Internal UART interface via Mini-USB connector. Configuration requires the service cable AC3006 or HygroSoft software. The device cover must be removed to access this interface, which is only permitted outside explosive zones.

Key Product Differences

The series distinguishes between wall and duct mounting configurations based on housing dimensions and weight. Probe selection varies by application environment: the HC2-SM-EX is a short probe for direct insertion, while HC2-IMxxx-EX models provide extended reach via cable lengths of 2 m, 5 m, or 10 m with varying sensor head lengths (125 mm vs. 285 mm). Screw-in probes (HC2-IExxx-EX) offer threaded connections in either ½" G or ½" NPT formats.

Temperature class variations affect the maximum operating temperature of the sensor: T5-rated sensors support up to +60 °C ambient, while T4-rated sensors extend this range to +85 °C. The presence of an optional LCD display reduces the lower limit of the transmitter's operating temperature from -40 °C to -10 °C.