Analytical Technology A15 Spezifikationen PDF herunterladen (Seite 38)

ATI A15/66 Residual Sulfite Monitor

O&M Manual

Rev-W (8/10)

TROUBLESHOOTING

If you experience problems during the operation of a sulfite monitor, refer to the information below

to isolate the source of the problem.

During calibration, monitor indicates “Sensitivity < 20 %” and calibration does not update.

1. Check sensor membrane for fouling or excessive water accumulation. Clean the sensor membrane

with distilled water and dry with a Q-Tip or lint free wipe if fouling is observed. Replace sensor if

necessary.

2. Check the “zero offset” entered into the monitor. You can view this value by going to display D2 and

pressing CAL once. The display will read “zero: X.X nA”. Normally, the zero offset is less than -200

nA. If a large offset is present, rezero the system in accordance with this manual.

3. Check to see that the acid is being delivered by the reagent pump. To test this, turn the sample inlet

valve to the distilled water position but do not connect tubing to this hose barb. Allow the sample

pump to draw in air instead of liquid. Disconnect the acid tube from the “T” fitting where the acid is

mixed with the sample.. Allow the system to run and observe the outlet from the tube. A small drop

of acid should slowly grow at the end of the tube if a continuous flow of reagent is being delivered. If

the tube does not show good flow, replace the reagent pump tube.

4. Check monitor configuration menu, step 7, to verify that the polarity is set to 0 mv. With a digital

voltmeter (DVM), measure the voltage between terminals 18 and 19 on the back of the monitor to

verify that the millivolt value is actually 0 mv. Note that a reading of 1 or 2 millivolts in not unusual

and does not indicate a problem.

Monitor values are unstable or the LCD is indicating negative values.

1. Check the “zero offset” entered into the monitor. You can view this value by going to display D2 and

pressing CAL once. The display will read “zero: X.X nA”. Normally, the zero offset is less than -200

nA. If a large offset is present, rezero the system in accordance with this manual.

2. Check reagent delivery as described in step 3 above.

3. Check the sensor membrane condition. A membrane that is punctured will cause unstable

measurements. If necessary, replace the sensor.

Monitor display does not come on or 4-20 mA output signal is inoperable.

1. Check to see that you have AC power on the terminals at the back of the monitor. Check all

terminals for tight connections.

2. If 4-20 mA signal is incorrect, check resistance of the load on the output to verify it is under 600

ohms.

3. Most electronic component problems are not repairable in the field. Contact ATI service department

to arrange for factory repairs if electronics do not function.

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Analytical Technology A15 Spezifikationen Seite 38