Operation; Start-Up And Polarizing - Mettler Toledo InPro6900 Bedienungsanleitung

16
5

Operation

Attention! Before using the sensors for the first time,
the electrolyte should be replaced (see «Chapter 6.2»).
Due to possible adverse conditions during transport
and storage (e.g. airfreight; pressure and temperature
variations), the quality of the electrolyte may become
impaired. Poor electrolyte quality can lead to erroneous
measurement values.
5.1

Start-up and polarizing

Attention! The watering cap must be removed before
mounting the sensor in the process.
When the system is operated for the first time or if the
sensor has been disconnected from the voltage source
(transmitter or O
min utes, the sensor has to be polarized prior to cali-
bration by connecting it to the operating O
or to a sensor master. After 6 hours, the sensor is fully
polarized and ready for operation. During this time, it
is recommended to keep the watering cap filled with
conditioning solution on the sensor (see «Section 7 -
Storage»), especially if the sensor is being polarized
for longer than 6 hours.
A shorter polarization period is sufficient if the sensor
has been disconnected for only a few minutes. The fol-
lowing table serves to establish the correct polarization
time in relation to the depolarization time.
Depolarization time
t
depol
30 > t
15 > t
Depolarization time:
1)
Time span in which the polarization voltage is cut off from
the sensor. This is the case during:
– change of electrolyte
– change of membrane body
– the time the cable is disconnected or no transmitter or sensor
master is connected to the cable
Polarization time:
2)
Time span during which the sensor is under a polarization
voltage.
Attention! Setting of the polarization voltage on the
transmitter for correct measurements:
– Standard applications (e.g. measurement in bio t ech -
nology):
– Measurement of permanently low oxygen concentra-
tions <500 ppb in the presence of volatile acidic
components (e.g. carbon dioxide during measure-
ments in breweries): -500 mV
InPro 6900
52 201 029
InPro 6900 Series O
Sensor-Master) for longer than 5
2
[Min.]
t > 30
depol
> 15
depol
> 5
depol
t < 5
depol
1)
Minimum required
polarization time
6 * t
4 * t
2 * t
-675 mV
© 12 / 15 Mettler-Toledo GmbH
Sensor 12 mm
2
transmitter
2
2)
[Min.]
360
depol
depol
depol
Printed in Switzerland