16
…6
START UP AND OPERATION
D.O.
g/kg
Temperature ( C)
SENSOR CAL.
– – – – –
1 8 1
2 0 0
.
High Set
g/kg
1 5 0
Open Valve
NO
YES
.
°
.
Sensor Eff
– – – – –
Low Set
g/kg
5 0
.
– – – – –
Sensor O/P (
A)
– – – – –
6.1
Instrument Start-up – Fig. 6.1
Ensure all electrical connections have been made and switch on the power supply. If the instrument is being commissioned for the
first time, calibration and programming of parameters is required.
The overall operating and programming chart is shown in Fig. 6.1.
6.2
Operation – Dissolved Oxygen Measurement Mode
Operation in the Dissolved Oxygen measurement mode comprises an
Operating Page
and a
Calibration Page
. The
Operating Page
is
a general use page in which parameters are viewed only and cannot be altered. To alter or program a parameter, refer to the
programming pages in Section 7. The
Calibration Page
allows a calibration to be carried out. A 5-digit calibration code is used to
prevent unauthorized access to the sensor calibration page. The value is preset at 00000 to allow access during commissioning, but
should be altered to a unique value, known only to authorized operators, in the
Set Up Alarm page
– see Section 7.2
6.2.1
Operation Page
Measured Dissolved Oxygen
The measured dissolved oxygen is displayed in µg/l, mg/l, ppb, ppm, mg/kg or µg/kg.
Auto ranging:
0.0
to 99.9 µg kg
–1
100
to 999 µg kg
–1
1.00
to 9.99 mg kg
–1
10.0
to 20.0 mg kg
–1
Press
to advance to next parameter
or
press
to advance to
Calibration Page
,
Section 6.2.2.
Sample Temperature
The sample temperature is displayed in either °C or °F – see Section 7.1.
Sensor Output
Raw current signal (µA) generated by the sensor.
Sensor Efficiency
Bar graph indication of the sensor performance, based on last calibration – see Section
6.2.2.
High Setpoint
The
High
alarm setpoint value is only visible if the alarm is programmed for either D.O. or
Temperature and is set to
High
or
High/Low
.
Low Setpoint
The
Low
alarm setpoint value is only visible if the alarm is programmed for either D.O. or
Temperature and is set to
Low
or
High/Low
.
Open Valve
Manually open the calibration valve to drain the flowcell prior to accessing the sensor. The
reading displayed when the valve is open does not represent the dissolved oxygen
content of air-saturated water at the prevailing ambient temperature.
Advance to
Calibration Page
, Section 6.2.2.
