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計測機器 Aqua Metrix P/R65のPDF 取扱説明書をオンラインで閲覧またはダウンロードできます。Aqua Metrix P/R65 20 ページ。 Differential 2-wire (4-20 ma) ph & orp probes

5. 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):

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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