I have some temperature data loggers that may need some calibration and received a response from the manufacturer on calibration procedures. Basically, I need a little help in understanding the procedures and results of calibration.
The procedure is as follows:
(not shown: ambient lab temperature was logged at 23.1 °C in cell b11)
I guess my first questions are:
1) If the ref voltage is 4096 mV, why are the calibration values represented as negative uV?
2) When checking the ref voltage what does it mean by 'the analog circuits will be switched on permanently'?
These are Eltek 1000 series squirrel loggers if anyone is familiar with them.
regards,
Dave
The procedure is as follows:
Here is part of the spreadsheet of a sample logger that was calibrated:If you feed in zero mV and read off the temperature it should read exactly ambient. Enter this figure in the cell marked Lab Temperature (B11). This figures on the right hand side of each range are the mV values to feed in to the instrument to check the calibration.
If the resulting readings are not correct then there is a problem with the instrument. The only adjustment that is possible is to the reference voltage which is 4096mV. This is adjusted using pot RV2 also marked 4096. To check this, select the Meter function and press the Set button for 5 seconds. The analog circuits will then be switched on permanently. Measure the voltage across the ends of the pin header SK1 which is in the middle of the circuit board.
Note that in the attached spreadsheet, the column marked "Instrument reading" are the values obtained when calibrating an actual instrument.
(not shown: ambient lab temperature was logged at 23.1 °C in cell b11)
I guess my first questions are:
1) If the ref voltage is 4096 mV, why are the calibration values represented as negative uV?
2) When checking the ref voltage what does it mean by 'the analog circuits will be switched on permanently'?
These are Eltek 1000 series squirrel loggers if anyone is familiar with them.
regards,
Dave