Aqua Metrix P/R65 Instrukcja obsługi - Strona 10
Przeglądaj online lub pobierz pdf Instrukcja obsługi dla Przyrządy pomiarowe Aqua Metrix P/R65. Aqua Metrix P/R65 20 stron. Differential 2-wire (4-20 ma) ph & orp probes
Drukuj stronę5. TROUBLESHOOTING AND SERVICE
5.1.
Checking Probes P65 and R65
The operation of the 2-wire, 4-20 mA probe can be checked by a few simple measurements. For the P65
two pH buffer solutions, pH 7 and either pH 4 or pH 10, and an ammeter are required.
5.1.1.
P65 pH Probes
1. Disconnect the red wire at the instrument or power supply and connect it to the milliammeter (-)
black.
2. Connect the ammeter (+) red to the instrument or power supply red wire output terminal.
3. Rinse the probe and place it in 7 pH buffer. Allow the temperature of the buffer and probe to
stabilize at room temperature.
4. Check the offset of the probe by reading the ammeter. The reading should be between 11 and 13
mA. If not the probe is defective. If the offset is OK, note the exact reading and proceed to the next
step.
5. Rinse the probe and place it in 4 pH or 10 pH buffer. Allow the temperature of the probe and buffer
to stabilize at room temperature. Now check the span of the probe by reading the ammeter. If the
probe is in pH 4 buffer, the reading should be between 2.85 and 3.99 lower than the reading
obtained in (d).
6. If the probe is in pH 10 buffer, the reading should be between 2.85 and 3.99 higher than the reading
obtained in (d).
7. If this test is not satisfied the probe is defective.
8. If you wish to check the temperature compensator proceed to step (f).
9. If the span of the probe drops below 2.85mA than the probe still can be used adjustments will have
to be made to the receiving device to compensate for the low span.
10. To check the operation of the temperature sensor in the probe, heat the buffer used in step (e) with
the probe in it to about 50°C. The ammeter reading should be within ±0.15 mA of the reading
observed in step (e).
5.1.2.
R65 ORP Probes
1. Disconnect the red wire at the instrument or power supply and connect it to the ammeter (-) black.
Connect the ammeter (+) red to the instrument or power supply red wire output terminal.
2. For a probe with range of –500 to 500 mV (white and green wire open):
a. Rinse the probe and place it in the 200 mV solution. The ammeter should read between
13.7 and 16.7 mA.
b. Rinse the probe and place it in the 600 mV solution. The meter should read between 19.44
and 23.8 mA.
3. For a probe with range of 0 to 1000 mV: (white and green wire joined):
a.
Rinse the probe and place it in the 200 mV solution. The ammeter should read between
6.4 and 8.0 mA.
b. Rinse the probe and place it in the 600 mV solution. The meter should read between 12.2
and 15.0 mA.
P/R65
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