Grundfos Conex DIS-D Instrucciones De Instalación Y Funcionamiento página 21

Error messages when reading in the voltage
signal of the pH combination electrode
• The alarm LED flashes.
• The coded display output flashes.
*13*: Gradient error
The alarm is displayed if the plausibility check of the
pH calibration data establishes an upward/downward
violation of the gradient range from -50 to -62 mV/
pH.
*14*: Asymmetry error
The alarm is displayed if the plausibility check of the
pH calibration data establishes an upward/downward
violation of the accuracy range from -60 to +60 mV.
*10*: Auto read time-out error
The alarm is displayed if the combination electrode
does not reach a stable signal within the defined time
period (120 s).
*11*: pH difference
The alarm is displayed if a fault exists in the
combination electrode or if an incorrect buffer has
been used (difference in pH of selected buffer
solutions < 1.00 pH).
• The calibration procedure is aborted in all four
cases.
• Press [OK] to acknowledge the error message
and return to the display level.
• No new calibration data are imported; the old
calibration data are not overwritten!
Calibration result
• The result of the current (last) calibration can be
displayed in the code menu at any time:
– Code 51: display of calibrated gradient in mV/
pH
– Code 52: display of asymmetry potential in mV.
9.6.7 Calibration of redox value; Conex
• The redox calibration is carried out by
determining the redox offset compared to a
reference solution (e.g. Grundfos redox buffer
220 mV, order No.: 96609166).
1. Press [Cal] to select the calibration menu.
The Cal LED next to the [Cal] button illuminates.
– To prevent overdosing, the controllers are
switched off and the actuators closed.
– The buffer value 220 mV appears
automatically.
2. Use the [Up] or [Down] button to change to the
value of the used buffer.
3. Fill redox buffer from the supply bottle into a
clean vessel.
4. Immerse the combination electrode into the
buffer solution.
5. Start the automatic read function AUTO READ
(reading in of measured signal) and the
calibration by pressing [OK]. The buffer value is
displayed flashing.
During the redox calibration, the automatic read
function ensures that the correct electrode signal
is only read in for the buffer value if the measured
signal remains stable for a defined period of time.
6. Discard the buffer solution (i.e. do not return it to
the supply bottle!), Flush the combination
electrode with water.
The calibration result is automatically displayed
directly after the calibration:
– Redox offset in mV.
7. Return to the display level by pressing [OK].
Error messages when reading in the voltage
signal of the redox combination electrode
• The alarm LED flashes.
• The coded display output flashes.
• Redox offset is flashing.
*14*: Asymmetry error
The alarm is displayed if the plausibility check of the
redox calibration data establishes an upward/
downward violation of the accuracy range from -60 to
+60 mV.
The calibration procedure is aborted.
• Press [OK] to acknowledge the error message
and return to the display level.
• No new calibration data are imported; the old
calibration data are not overwritten!
Calibration result
• The result of the current (last) calibration can be
displayed at any time in the code menu:
– Code 52: display of redox offset in mV.
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