EIJKELKAMP 14.36, Руководство по эксплуатации

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2.3 Checking the instrument
Checking general:
. Check if the batteries are fresh
Check Redox measurements:
. Switch instrument to Redox position
2. Apply voltage between “Pt electrodes and “ref. electrode”
between 0 and 2000 mV.
For a rough check you may use a 1.5 Volt penlight battery.
3. Display reading should be within 3 mV accuracy of applied
voltage.
Check ODR reference voltage:
In the kit going with the meter you will find a resistance soldered to
some wires. Use this simple tool for the next check.
. Short circuit input brass electrode to input ref. electrode.
2. Connect resistance 820 ohms between input ref. electrode and
input PT electrodes
3. Switch instrument to position
4. At 820 ohms dsiplay reading should be 793
(+1 ohm -> -1 mV : 830 ohms -> reading 783 mV)
(-1 ohm -> +1 mV : 810 ohms -> reading 803 mV)
Check probe connections:
. Check inputs and connections for corrosion and moisture (also on the instrument)
2. Check cables between middle pin connectors, resistance < ohm
3. Check cables between outside connectors, resistance < ohm
4. Check resistance reference electrode silver part (head without body) to middle pin connector, resistance < ohm.
5. Check Pt electrode point resistance to middle pin connector, resistance < ohm.
6. Check brass electrode to middle pin connector, resistance < ohm.
Check redox potential of electrodes:
Use a Zobell kalibration solution to check the electrodes for redox measurements. The measurement value must be
near the certified value of the Zobell solution (e.g lab temperature 21 °C, reference electrodes filled with 3 M KCl,
measurement value must be near 228 mV). Stirr with de-aeration a little bit open.
Which value will you get ?
This depends on the temperature and type of reference-electrode. The values are shown in the table on next page.
First you need to know the temperature of the (calibration) solution and the used reference temperature. Generally
a field or normal lab electrode will be a Platinum-silver combination type electrode with 3 Mol KCl liquid (saturated
with AgCl) as electrolyte.
Warning: The table is established using data from the Zobell-solution supplier (in Italics) and from the Austrian and
DIN standard. Missing but usefull data have been extrapolated and are marked with *.
Use the grey marked column for the 3 M KCl electrodes supplied by Eijkelkamp.
820 ohm