The Rotronic HF5-EX series is a high-precision, two-channel humidity and temperature transmitter designed for use in hazardous, explosive atmospheres. Built with a robust aluminum housing and certified to international standards, it's ideal for critical industrial applications.

VERSIONS 

HF520-EX-W – Wall Version

• Robust aluminum housing (IP66)

• Integrated EX-approved stainless-steel probe (HC2-SM-EX)

• LCD (optional) for local indication

• Suitable for ATEX Zone 1/21
  

HF520-EX-D – Duct Version

• Same aluminum transmitter as wall version

• Probe mounted through duct using AC1301-MEX gland

• Uses HC2-SM-EX or HC2-IM-EX probes

• Suitable for ducts in hazardous areas
  

Wall Version with Cable Sensor (Flexible Probe)

• Remote EX cable probe: HC2-IMxxx-EX

• 2 / 5 / 10 m cable lengths

• 130 / 280 mm stainless-steel probe

• Good for placement away from electronics and confined spaces
  

Wall Version with Screw-In Sensor

• EX screw-in probes: HC2-IExxx-EX or HC2-LDPxxx-EX

• ½” G or NPT threaded connection

• Suitable for pressure pipes, low dew point, or high-pressure HVAC

Key Features 

• ATEX/IECEx approved for Zone 1/21 (transmitter) and Zone 0/20 (probes)

• Stainless-steel EX probes

• Measures RH, Temperature & Dew Point

• Two scalable analog outputs (2 × 4–20 mA, two-wire)

• IP66 aluminum enclosure

• LCD display optional

• Interchangeable EX probes

• Power supply: 10–28 VDC
  

Technical Specifications 

Parameter	Value
Humidity Range	0–100% RH
Accuracy at 23°C	0.8% RH / 0.1 K
Temperature Range	–40…60°C or –40…85°C (probe-dependent)
Outputs	2 × 4–20 mA (2-wire)
Housing	Aluminum EN AC-AlSi12, IP66
Display	Optional LCD (no backlight)
Start-Up Time	<60 s cold / <30 s warm
EX Protection	II 2(1)G Ex eb mb [ia Ga] IIC T5 Gb
Probes	HC2-SM-EX / HC2-IM-EX / HC2-IE-EX / HC2-LDP-EX

Applications 

• Hazardous industrial zones

• Petrochemical plants

• Pharmaceutical production

• ATEX HVAC systems

• Silos, dust-hazard zones

• Pressure pipes & low-dew-point monitoring

What’s in the Box

• HF520-EX transmitter (Wall / Duct / Cable Probe / Screw-in Probe version)

• EX probe (model-dependent)

• Cable gland AC1301-MEX (for duct/cable types)

• Mounting hardware

• Documentation

❓ FAQ 

Q: Are the probes interchangeable?
Yes, all EX probes (HC2-SM-EX, IM-EX, IE-EX, LDP-EX) can be swapped.

Q: Can this model measure dew point?
Yes, all psychrometric calculations are supported.

Q: Can I calibrate the probe in a safe zone?
Yes—probes can be removed and calibrated outside the EX area.