• Ex-protection version of the iPR-B3
  • Suitable for all applications in explosion-proof areas
  • Certified according to European Classification ATEX II 1 G Ex ia IIC T4 Ga
  • Permanent inline real-time measurement of the concentration of dissolved solids

Automatic process refractometer iPR – EX

Fully automatic process refractometer for direct measurement of dissolved solids, process monitoring and control. Principle of the critical-angle refractometer with sapphire prism and high-resolution photodiode array; no influence of color and opacity of the medium on the measuring result. Measuring head made of stainless steel, chemical resistant, food safe, hygienic, for process temperatures up to 120 °C (with connected water cooling) and pressures up to 1 MPa.

The explosion protection version of the process refractometer consists of an intrinsically safe, single-certified sensor, which is installed in the hazardous area. The measuring signals are routed to the non-explosive area via a special cable (maximum length 500 m) and connected to 4 zener barriers. The connection to the central control system is realized with a RTU Modbus or serial RS 485 interface.

Alternatively, Schmidt + Haensch offers a control unit, which is also installed outside the hazardous area. The 7 “touch screen is individually configurable. The measured data can be output via Ethernet as a 24 V or 4-20 mA signal or control a relay.

For data transmission to other systems, serial RS 232, 485 interfaces, a CAN bus or UPC server are available.

Up to two measuring heads can be connected at the same time.

Main specifications

StandardsATEX II 1 G Ex ia IIC T4 Ga
IEC in preparation
Measuring range1,32000 – 1,52000 nD
Resolution0,00001 nD
Precision±0,00014 nD


Ambient temperature-20 °C to +65 °C
Process Temperature-20°C to +120 °C*
Temperature resolution/precision0.01°C / ±0.2°C (0° to 70°C)
Process pressure0 to 1 MPa (145 psi, 10 bar)

Additional informationen

Wetted partsSapphire (prism), stainless steel, FKM
Protection classIP 67
Light source / wavelengthLED, 589 nm
Interface, switchesModBus, RS485 and 24V with external Zener barriers
Dimensions330mm x 149mm (length x diameter)

Control unit

Operation1 and 2 measuring headsets are available, connectable with built-in Zener barriers
Display7″ Touchscreen, 800×480 pixel
DIN rail parts (expandable)Switch inputs (24 V) and outputs (24 V / relay / 4-20mA) / Communication (RS232 / RS485), CAN, UPC Server
HighlightsConfiguration of measuring head and outputs / Adjust switching thresholds and analog outputs /
Concentration and other scales user programmable
Power85V … 265V 50/60Hz

* with cooling by cooler circuit only, electronic max. +65°C