Problems with DFR0300-H Electrical Conductivity Sensor

userHead Account cancelled 2019-05-01 14:05:12 1259 Views0 Replies
Hi, I have a high quantity of your DFR0300-H Electrical Conductivity K=10 sensors that were manufactured in March of 2019 according to the stickers on the boxes.

I've tested about 9 of them so far and all of them are giving me high values of 20 to 30 ms/cm when I immediately test them for the first time after opening the boxes and putting the probes in the 12.88 ms/cm buffer solution. I am using the EC10 libraries and default example code to check values and calibrate. I also have the correct temperature in the fluid and am using the DS18B20 temperature sensor.

When I let the probe sit in distilled water for 5 minutes and then let dry and put back in the buffer solution I see the value drop a little more to maybe 19 ms/cm to 17 ms/cm. Sometimes I can then use ENTEREC and calibrate with CALEC and it reads 12 ms/cm and then I use EXITEC to save the values. Sometimes the values drop to 9 ms/cm after letting sit for a while and trying again in the buffer solution but when I try to recalibrate again with the same technique I get a message saying Failed Try Again. If I clear the memory on the EEPROM and retry again I still get the Failed Try Again message. Is there a way to fix this?

Also why are the sensors reading such high values when I initially put them in the 12.88 ms/cm buffer solution?