Dear Users & Support,

I'm having troubles in setting up a second CEM extension into my DT80 series 3 logger. I have successfully connected one CEM20 extension into the datalogger channel 1. However, when I try to do the same for a second CEM20 connecting it to channel 2, I keep getting RefError while reading the measurements from the command line interface.

I'm sure the sensors are working fine because I can easily read their data when I connect them to CEM20 - CH1. The second CEM20 is correctly powered, and it is sampling and the To Logger port is correctly connected to CH2 in the logger. Do you have any suggestions to troubleshoot these errors?

Hi Danib,

Each CEM20 needs slave address depending on the connected terminal in the logger. If you connect CEM20 to terminal 1, this CEM20 will need address 1. The address setting follows binary representation which you can set on the dip switches (left panel of CEM20). Address 1 means switch 1 to 4 has the following setting: OFF-OFF-OFF-ON.

In your case the second, it is possible the dip switch on the second CEM does not meet the correct terminal number. Address 2 means switch 1 to 4 has the following setting: OFF-OFF-ON-OFF.

Best regards,
dataTaker Expert