TESTO 6681 Instruction Manual page 100

testo 6610
100
2.2.7.1
Use in harsh ambient conditions with aggressive media in some cases incurs
the risk of damage to the sensor.
Damage to the sensor is generally reflected by incorrect readings which
occur a long time before the sensor is wrecked. If this damage to the sensor
is not spotted until too late, high costs can be incurred due to unusable
readings or machine shutdowns and waiting times until the sensor is
replaced.
The testo 6617 has a unique self-monitoring function. This allows early
detection of damage to the sensor, e.g.:
Mechanical damage (e.g. scratches)
•
Damage from aggressive gases (e.g. acids in aerosol form)
•
Welling or detachment of polymer layer due to effects of solvents.
•
Once the self-monitoring reaches the specific limit value, the probe warning
message "Sensor early warning" is issued.
- 2.2 Product description
This probe does NOT have a longer life with exposure to
aggressive media than the testo 6613, for example. However,
early warning of damage to the sensor is given so that
machine failures can be avoided.
Self-monitoring of cover electrode
1 Cover electrode
2 Bottom electrode
3 Substrate
(Ceramic substrate for
mechanical protection)
4 Connections
(protected against corrosion)
5 Dielectric layer