PART THREE - OPERATION
SECTION 7 - OUTPUT SETUP
Rev. 9-898
Model 692P
-41-
The operator has 30 minutes to complete the calibration
of this point. During the routine, pressing any key except
END CAL
provides another 30 minutes if needed.
The instrument checks:
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The stability of the pH and temperature inputs. As
each input changes, the respective pH and
°
C (or
°
F)
indicator flashes. When each input is stable, the re-
spective indicator stops flashing and remains on.
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That the pH input is within
±
0.75 pH of the buffer
value. When outside this range, the display flashes
“OUT”; within this range the “OUT” indicator goes off.
When these conditions are met, the display will indicate
“LO CAL VALUE” or “HI CAL VALUE,” depending on
which buffer the sensor is in.
3. When display indicates “LO CAL VALUE” or “HI CAL
VALUE” and the pH and
°
C (or
°
F) indicators are both on
(not flashing), press recessed
END CAL
button using a
slender tool. The displayed identifier and value goes off,
“OK” flashes for 5 seconds to confirm entry and the dis-
play returns to the pH measuring mode.
4. If a second calibration point is used, remove sensor from
first buffer. Rinse sensor in clean water and place in the
second buffer.
5. With display in pH measuring mode, press
BEGIN CAL
key. See step 2 for additional details.
6. Perform step 3.
This completes the “two-key” table pH calibration.
SECTION 7 - OUTPUT SETUP
7.1 Using Range Expand
Feature
The isolated 4-20 mA analog output can represent the en-
tire pH measuring scale or a desired segment of it. Use the
LO OUT VALUE and HI OUT VALUE setup variables to
enter low and high endpoints of the segment at which 4 mA
and 20 mA is desired. Note these important points:
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The desired segment, represented by the 4-20 mA
output, cannot be smaller than 1.00 pH unit.
