Hach lange have recently introduced a new range of probes for the HQD meters including an ORP or Redox probe. Older meters don’t have the firmware to handle these digital probes so an update is required. Simply attach the USB interface to the Hach HQ40D, download the firmware update and follow the instructions in the PDF.
Once the software is installed the meter will recognise the new probes automatically.
Contact firstname.lastname@example.org for more details and instructions