Hach ORBISPHERE 410 Manuel D'utilisation Simplifié page 18

Option
Display
resolution:
Thermal cutoff:
2. TC sensor
The measurement configuration for a TC sensor is the same as for an EC sensor with the
addition of one extra selection criteria:
• Purge gas: From the drop-down list, select the purge gas being used for the TC sensor.
7.3.3 Measurement alarms configuration
Set the thresholds for the low/high concentration levels according to the application.
1. Select the Alarms button on the Measurement configuration screen:
Option Description
Low Low 2nd stage for too low concentration alarm.
Low 1st stage for too low concentration alarm.
High 1st stage for too high concentration alarm.
High High 2nd stage for too high concentration alarm.
Hysteresis The hysteresis is used to prevent relay flickering when the measurement is just at
the alarm levels. Set this to a minimum but enough to eliminate flickering. For
example, if the High Alarm is set to 40 ppb and the Hysteresis is set to 10% then
the High Alarm is activated once the measurement reaches 40 ppb but only
deactivated once it drops below 36 ppb. With the Low Alarm the opposite is true in
that if the Low Alarm is set to 20 ppb and the Hysteresis set to 10% then the Low
Alarm is activated when the measurement drops below 20 ppb and deactivated
when it rises above 22 ppb.
Delay The delay in seconds, before alarms go on whenever concentration values go
above "High alarms" or below "Low alarms". Set this to a minimum value, but
enough to avoid alarms for non-representative peaks beyond the set level.
7.3.4 Measurement filter configuration
The filters are aimed at "flattening" the measurement curve in situations where the process shows
atypical peak values that could otherwise hamper the interpretation of measurement readings. The
filter is applied on the last set of measurements each time a measurement is taken.
1. Select the Filter button on the Measurement configuration screen:
Option Description
State Set the filters to Enabled or Disabled.
18 English
Description
Maximum resolution depends on gas, membrane and unit. A maximum of
5 digits can be displayed. Decimals can be limited to 0, 1, 2 or 3 decimals for
easier reading. That does not affect the actual resolution of data measured
and stored, but only the data displayed.
To protect the sensor, the thermal cutoff function allows for setting a sample
high temperature limit. If exceeded (during a Cleaning In Place cycle for
example) the electrical signal to the sensor is cut off, the measurement
session is suspended and the system displays a HOT alarm message. The
system resumes when temperature drops to 90% of the specified cutoff
temperature.
• Thermal cut off options: Disabled / enabled.
• Thermal cut off temperature: To be set according to conditions.