conductivity S ADC values

[Himat]

Hi

what should the ADC values be for conductivity I have calibrated the probe and the values i have are Value 1 0 ms ADC1 19 and value 2 50 ms ADC2 90

are these correct or is my probe reached its end,
the probe is 2+yrs old. using P3 ex and latest software.

Himat

[Matthias]

value 1 is OK, second value too low (should be something between 400..600)

is the measurement range (freshwater / seawater)ok? calibration fluid value?

[Himat]

hi
calibration fluid is 50ms ghl
measurement range is seawater

Himat

[Matthias]

this is strange - if the probe would be defective then it had either a short-circuit or open contact - in both cases the ADC values would be the same

could you try calibration again and check very closely if everything is really correct?

[Himat]

tried calibration the value2 is now lower at 82 than before at 90
also put probe in cleaning solution overnight before calibration

Himat

[Matthias]

we should find now the source of the problem - ProfiLux or probe?

please do this
start again calibration, we use the calibration process now only to determine the measured ADCs
leave the conductivity port open - which ADC occurs?
now connect the redox-null-plug there (this produces a short circuit) - ADC value?

[Himat]

hi
Matthias

do i do this on one calibration value 1 not connected value2 use null plug

[Himat]

hi
Matthias
I have done what you said the readings for ADC1 19 and ADC2 1023


Himat

[Matthias]

this shows that ProfiLux is working correctly

maybe "only" the BNC plug of your probe is defective - if you have the opportunity then you should try to replace it

[Himat]

hi
Matthias

is there any way to check the connection on the probe without replacing the BNC plug

at the moment the recalibration the ADC1 19 and ADC2 75
the reading seams correct.
How long are these platinum probes to last in normal usage.

Himat

[Matthias]

the platinum sensors should last "forever" when they are not physically damaged

but 75 is too low - it works but the measurment is not as precisely as it should be - are you really sure that the calibration fluid and the measurement range are correct?

[Himat]

hi
Matthias

I have the correct settings and the fluid is 50ms GHL and my older solution was aquamedic 52ms solution both solution give relatively same ADC2 value

as you said the reading of the probe after calibration and some time read correctly but to day it is reading higher,

all this has happened after my p3 upgrade, because recalibration of all probes

i have had the profilux since 2006 very happy with it and you have said my profilux is good earlier post.

is there a way to test the probe from BNC to the probe plates on the tip.

i will only buy a new probe as a last resort as the cost £130 is quite a lot and would like to spend that on new profi view when released.

Himat

[UK-GHL]

Hi Himat,

As I offered to you last week, if you pop it back in the post to us, we will check it out for you. You have my address and phone number.

Thanks

Steve

[Himat]

hi
ok i will have it in the post to you tomorrow

thanks

Himat