Hach pHD sc Analog Differential pH/ORP Sensors Manuel D'utilisation page 13

6. Select the option for the output signal during calibration:
Option Description
Active The instrument sends the current measured output value
during the calibration procedure.
Hold The sensor output value is held at the current measured
value during the calibration procedure.
Transfer A preset output value is sent during calibration. Refer to
the controller user manual to change the preset value.
7. With the sensor in the first reference solution, push ENTER.
The measured value is shown.
8. Wait for the value to stabilize and push ENTER.
Note: The screen may advance to the next step automatically.
9. If the reference solution is a sample, measure the pH value with a
secondary verification instrument. Use the arrow keys to enter the
measured value and push ENTER.
Note: If a pH buffer not listed the Cal Options menu is used, refer to the buffer
bottle to find the pH value that corresponds to the temperature of the buffer.
10. For a 2-point calibration, measure the second reference solution (or
sample):
a. Remove the sensor from the first solution and rinse with clean
water.
b. Put the sensor in the next reference solution and push ENTER.
c. Wait for the value to stabilize. Push ENTER.
Note: The screen may advance to the next step automatically.
d. If the reference solution is a sample, measure the pH value with a
secondary verification instrument. Use the arrow keys to enter the
measured value and push ENTER.
11. Review the calibration result:
• Passed—the sensor is calibrated and ready to measure samples.
The slope and/or offset values are shown.
• Failed—the calibration slope or offset is outside of accepted limits.
Repeat the calibration with fresh reference solutions. Refer to
Maintenance on page 16 and
more information.
12. If the calibration passed, push ENTER to continue.
13. If the option for operator ID is set to Yes in the Calibration Options
menu, enter an operator ID. Refer to
on page 15.
14. On the New Sensor screen, select whether the sensor is new:
Option Description
Yes The sensor was not calibrated previously with this
controller. The days of operation and previous calibration
curves for the sensor are reset.
No The sensor was calibrated previously with this controller.
15. Return the sensor to the process and push ENTER.
The output signal returns to the active state and the measured
sample value is shown on the measure screen.
Note: If the output mode is set to hold or transfer, select the delay time when
the outputs return to the active state.
4.4.3 ORP calibration procedure
Sensors can be calibrated with an ORP reference solution or with the
process sample.
1. Put the sensor in the reference solution. Make sure that the sensor
portion of the probe is fully immersed in the solution
Troubleshooting on page 17 for
Change calibration options
(Figure 5).
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