Hach 51 Series User Manual page 17

Option
Measurement
interval
Hold recovery time
Measured data storage
There is one measurement file per channel which contains the data generated by the measurement
cycle.
1. Storage modes:
Option Description
No storage Storage is disabled.
Store once When the volatile memory is full (10,000 positions), the recording of measurement stops.
Rolling buffer When the volatile memory is full, the latest measurement set replaces the oldest one
continuously (first-in, first-out).
Calibration
Calibrations can only be performed once the instrument has been installed and configured.
Note: The temperature sensor is factory calibrated and can only be changed by a Hach representative.
K-M1100 sensor calibration
Sensor calibration
The sensor can be calibrated manually on an ad hoc basis. By default, the mode is set to zero
calibration with auto-end.
For higher level concentrations (above 1% oxygen which corresponds to about 400 ppb dissolved
O ) a high level adjustment can be performed using a gas mixture containing more than 1% oxygen,
2
or a known line sample. However, this should not be done without first ensuring the zero point is
accurate. This can be achieved by performing a zero calibration first.
Low range sensors: (K-M1100-L spots)
There are two calibration modes available - zero or high level adjustment. The sensor is factory
calibrated at zero. During use, the zero calibration is the best calibration to guarantee the sensor
specifications. After a spot replacement, a zero calibration is recommended.
High range sensors: (K-M1100-H spots)
There are three calibration modes available - zero, high level adjustment or in 100% humid air. The
sensor is factory calibrated at zero and in 100% humid air. During use, humid air calibration is the
best calibration to guarantee the sensor specifications. After a spot replacement, a zero calibration
and a 100% humid air calibration are recommended.
Initial sensor calibration
The sensor has been calibrated at the factory prior to shipment and is ready for use upon delivery.
However, if the sensor has not been used for a period of more than six months since delivery or if the
sensor spot has been replaced or changed in any way, then a sensor calibration will be required.
Description
Set the value to between 2 and 60 seconds to define the interval for refreshing the
measurement value on the display.
Note: The minimum value for the measurement cycle interval is 4 seconds for
2 channels and 6 seconds for 3 channels
This parameter defines the interval during which the outputs remain frozen after the
measurement is no longer on HOLD. Set the value to between OFF and 10 minutes,
according to the timing of your setup.
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