OEM Module for Online pH Measurement

Electro-Optical Module EOM-pH-PHB50

The EOM-pH-PHB50 is a precise, single channel module for non-invasive pH measurement. It is compatible with sensor types HP5 & HP8 (pH 5.5 – 8.5). The small outer dimensions and low power consumption make it very easy to integrate this board in custom monitoring and control systems. EOM-pH-PHB50 uses RS232, RS485 or USB 2.0 as digital interface. A serial communication protocol is offered for data exchange between a PC or another host unit and the EOM. Additionally, the device has 4 to 20 mA analog output and a Pt100 temperature sensor interface for temperature compensation of the pH measurements.

  • Compatible with sensors type HP5 & HP8
  • Small dimensions & low power consumption
  • Communication via RS232, or RS485 (PreSens proprietary or Modbus RTU)
  • 4 to 20 mA (current sink) analog output
  • Pt100 temperature sensor interface
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Pharma Industry: pH Monitoring in Bags

Bags and single-use bioreactors are in the process of revolutionising the way biopharmaceuticals are manufactured. Our non-invasive pH sensors are the tools to make the cultivation vessels fully disposable. As non-invasive DO sensors are also available, the two key parameters oxygen and pH can be controlled online.

Simple Connection to PLC

PLC programming can be a challenging and time-consuming task. Establishing a stable working connection to third-party hardware via interfaces such as RS485 is error prone. PreSens offers you the right support! We provide LAD-schemes and SCL-scripts, the corresponding TIA-project files and even wiring tables to help you connecting your EOM boards to a Siemens-S7-(1200-)PLC, nearly instantly. Nothing stands in the way of further development into company-specific solutions such as process control. Contact our service team!


pH sensors HP5, HP8 (optical SMA connector)
Phase resolution 0.01°
Sampling rate 0.11 sec. – 599.9 sec.
Temperature sensor Four-wire Pt100 sensor interface
Temperature performance 0.1 °C + Pt100 accuracy
Supply voltage 5 – 28 VDC
Power consumption in active mode 0.75 W
Power consumption in stand-by mode 0.25 W
Temperature: operating / storage From 0 °C to + 50 °C / from - 10 °C to + 70 °C
Relative humidity 0 % to 80 % (non-condensing)
Dimensions (L x W x H) 94.2 mm x 25.0 mm x 19.6 mm
Weight 39 g
Digital interface RS232, optionally RS485 (PreSens proprietary or Modbus RTU)
USB 2.0
1Depends on hardware configuration and parameter settings. < 0.7 s only possible without temperature sensor.


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