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Measurement Menu
7.1 Instrument configuration
7.2 Measurement configuration
Continuous mode description
Continuous mode is typically used for process measurement. The measurement mode is a parameter
defined for the entire instrument, not for each channel.
Continuous mode cycle
• Every 2 sec. measurements are refreshed on the display
• The relays and the analog outputs are updated
• Measurements are continuously stored in memory (volatile and non volatile memory) according to
individual settings
Measurement mode is locked on Continuous. Select the units for barometric pressure and temperature.
TC sensor
• Sensor’s membrane number selection.
•Medium: Liquid or gas phase.
• Gas unit type: Partial, Fraction, Dissolved.
• Gas unit: The list of available units depends on unit type selected above.
Note: This is the gas concentration measured by the sensor. When a composite unit is selected (e.g.
ppm-ppb) the unit will change depending on the range of the value to display.
•Liquid: When medium is liquid, select water or a liquid with a different solubility (if available).
• Display resolution: 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.
• Thermal cutoff: 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. 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.
Advanced configuration - TC sensor
• Enable ext. pressure sensor: Check as appropriate. Refer to External pressure calibration on
page 64.
• Enable negative concentration: Check as appropriate.
• Hold recovery time: 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.
• Continuous purge during thermal cut off: If thermal cutoff has been enabled. Refer to
Measurement configuration on page 52.. Then check this box to ensure that a continuous purge of
the TC sensor takes place while the measurement session is suspended due to the thermal cutoff
temperature value being exceeded.
Note: To manually set the TC sensor into a continuous purge mode, press the Continuous Purge button
that is available from the Services - Diagnostic - Channel x - Amplifiers menu. Refer to TC sensor -
Amplifiers on page 99 for more information.
• Offset and slope corrections: Enable correction as appropriate.
• If enabled, the correction values for offset and slope must be entered. These values cannot be
negative.
• Liquid to gas factor: Enable correction as appropriate. If checked, the percentage correction factor
must be entered. This value cannot be negative.
Note: If you believe you need to enable these corrections, it is advisable to contact a Hach Service
Representative first.
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