RHE 42

Ex de Field Mount

With its advanced digital signal processing capability and in conjunction with our sensors, the RHE 42 can achieve an ultimate mass flow measurement uncertainty of 0.05 %, making it ideal for both filling and bottling or any kind of high accuracy/reliability plant flow or density measurement. Connectivity includes a full suite of communications buses including Foundation Fieldbus and Modbus TCP/IP. The RHE 42 is a well specified transmitter relevant for large scale plant and project opportunities.


  • Measures Mass Flow, Volumetric Flow, Density and Temperature
  • Outputs 2 x Analog, 2 x Frequency/Pulse, 2 x Digital Status
  • Inputs 2 x Digital
  • PC USB / RHECom, RS 485 / Modbus RTU, Modbus TCP, Foundation Fieldbus and Profibus PA
  • Optional Backlit Color LCD
  • Installation in Hazardous Area
  • Rheonik Assurance Factor®



General Specifications

Enclosure Material

Powder coated aluminum

Enclosure Rating

IP65/Type 4, optional IP66-67/Type 6

Ambient Temperature

-20 to +60°C  / -4 to +140°F, optional -40°C to +65°C / -40°F to 149°F

Integral version depends upon fluid temperature, refer to next page


Enclosure approx. 144 x 108 x 139 mm / 5.67 x 4.25 x 5.47 in

Weight approx. 2.3 kg / 5.1 lbs

User Interface and Configuration

Local Display Version

High contrast backlit LCD color display and 3 x through-glass operator buttons.  Configure locally or with RHECom software

Reduced display visibility below -10°C  / 14°F

Blind Transmitter Version

No local controls. Configure through RHECom software package

Connection to Sensor

Integral/Compact to sensor or remote mount with 3m/10m cable

Cable Entries

2 x ½” NPT for power and I/O

Computer Connection

Via Modbus RTU to PC


6 x resettable forward, reverse and net totalizers for mass and volume

2 x non-resettable totalizers for mass and volume

Analog Outputs

Up to 2 x 4-20mA outputs, active or passive.

Intrinsically safe versions available

Pulse/Freq/Status Outputs

Up to 2 configurable pulse/frequency/status outputs (IEC60946).  Max. 10kHz.  Intrinsically safe versions available (open collector)

Digital Inputs

Up to 2 configurable control inputs (IEC60946).

Intrinsically safe versions available

Digital Data Communications

HART, Modbus RTU, Ethernet (Modbus TCP/IPv4), Foundation Fieldbus H1 (FISCO), Profibus PA

Power Supply

12-24 VDC +/- 10%, 2W typical, 4W maximum

Hazardous Area Approvals