IOSI-01 signal converter

Read-Ox supplies a DIN rail mounted programmable converter (IOSI-01)  for the thermocouple mV-signal and for the oxygen cell mV-signal  (emf) from the sensor. The IOSI-01 converts these raw sensor mV-signals to three linear 4..20mA analog output channels for easy integration in the plant’s logging system. The IOSI-01 was especially designed for the various types of sensors provided by Read-Ox. By changing dipswitch settings, standard calculations and 4..20 mA output ranges can be chosen for the various sensors. Moreover, the end user may also program the IOSI calculations and 4..20 mA output ranges according to his own specific needs. Through its USB port the IOSI-01 can connected to a PC. With the specially developped PC software ImOxyConfig the IOSI can be configured, realtime measuring values can be  graphically represented and recorded.

The standard IOSI settings for the varous Read-Ox sensors can be found under following links:


The Read-Ox IOSI-01 signal converter has following features:

  •  Input channel  for the EMF (mV) of the oxygen cell (-1000 to +1000 mV)
  •  Input channel for the thermocouple  mV-signal
  •  High input impedance of the input channels (about 100MΩ) for accurate measurement
  •  Three galvanically isolatated analog 4..20mA output channels, 12..24V loop powered
  •  Input channels, output channels and power supply are galvanically isolated from each other
  •  Free choice of thermocouple type (B,E,K,N,R,S or T)
  •  Automatic cold junction compensation
  •  RS485 interface with modbus communication protocol
  •  One 0..20 mA analog input channel for a parameter from the plant’s process computer
  •  PC software ImOxyConfig for IOSI configuration and for graphical displaying/recording of realtime values
  •  DIN rail mountable casing, plug-in terminal blocks
  •  Can be powered by the USB interface
  •  Optional: In-situ measurement of sensor’s impedance to monitor sensor condition over time


Sensor impedance test

IOSI-01 impedanceboard 340x230

The IOSI can optionally be equipped with a small add-on board able to perform an impedance test of the probe. The internal resistance of the sensor is an indication of its conditon: a high impedance may indicate it is near its end of life and should be replaced soon.

Impedance test IOSI




In the data logging menu of the ImOxyConfig PC software program an impedance check can be performed and after the test the probe's impedance is automatically displayed.