Hach 51 Series User Manual page 18

1. From the Main menu, select Calibration followed by Gas sensor and then Configuration. Make
sure the parameters are set as follows:
Option
Auto-calibration
Manual-calibration
Hold during calibration or
verification
Zero calibration bottle
2. Exit from the configuration screen by pressing OK.
3. Select Calibration and perform a manual zero calibration as described in
on page 19. For high range sensors perform an additional 100% humid air calibration as
described in 100% humid air calibration (high range sensors only)
Manual calibration
Manual calibrations can be made at any time by following these steps:
1. Remove the sensor from the sample line.
2. Rinse the sensor head with clean water.
3. Wipe the sensor head with a clean soft tissue to remove any excess moisture.
4. If using the supplied calibration device insert the sensor into the sensor holder on top of the
calibration device. If not using the calibration device insert the sensor into the flow chamber.
5. Flow the calibration sample through the calibration device or flow chamber as applicable. If using
the calibration device fully open the valve on the pressure reducer to give a gas flow rate of
0.1 L/min. If you are not using the supplied calibration device with pressure reducer the maximum
allowable inlet pressure must be no more than 2 bar absolute.
Note: The manufacturer recommends to keep the flow chamber at atmospheric pressure. Adjust the sample
flow before it goes into the flow chamber.
6. Configure the calibration as described in
7. Start the calibration as described in
(high range sensors only)
preferred calibration method.
Calibration configuration
Note: This option can also be invoked by pressing the Modify button in either the Zero calibration or High level
adjustment calibration screens.
1. From the Main menu, select Calibration followed by Gas sensor and then Configuration.
Option
Auto-calibration
Manual-calibration
Hold during
calibration or
verification
18 English
Description
Not available for this sensor.
Make sure that the Auto-End box is checked.
Make sure this box is checked.
Make sure this is disabled by unchecking the box as it is not relevant
for this sensor.
Calibration configuration
Zero calibration
on page 19 or High level adjustment
Description
Not available for this sensor.
When Auto-End is enabled a manual calibration will complete automatically when the
parameters defined in Stop parameters are reached. Press on Configure to set the
manual calibration parameters. If the calibration fails, the previous calibration
parameters remain unchanged and a warning message displayed.
If checked this keeps the last measured value and stops updating the outputs during
the calibration or verification process. This avoids sending invalid information to any
connected device. At the end of a calibration, this hold remains on for a further
10 minutes to allow the system to stabilize.
on page 19.
on page 18.
on page 19, 100% humid air calibration
on page 20 depending on the
Zero calibration