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Checking the Data
Thermocouple probes are generally reliable, but damage resulting from
inappropriate use or handling can produce erroneous readings. If you suspect
that invalid data may have been introduced into your temperature profile
(paqfile), select the View Data tab in the Insight software's Analysis Window to
view the raw data as downloaded from the logger. The various types of invalid
data which may be contained in a paqfile are shown in the analysis grid as
follows.
*OC*
Open circuit.
*NA*
Telemetry data not received.
*LO*
Temperature measured was below the range of the logger.
*HI*
Temperature measured was above the range of the logger.
***
Calculation cannot be performed (not necessarily because the data are invalid). Does
not appear in View Data analysis mode.
Probes with an intermittent open circuit may produce spiky, erratic profiles.
Note that spikes are inevitable when probes are disconnected from a running
data logger. Typical causes of invalid or interrupted data are:
• Thermocouple becoming detached from the logger.
• Faulty connection.
Readings which are inconsistent with those of other probes may be caused by a
short circuit (see below). The probe concerned must be replaced.
Testing the Logger and Thermocouples
Although thermocouples are generally robust, they can be damaged during
handling. Use the following procedure to confirm the operation of logger and
thermocouples after installation. Note that this test is not an alternative to
calibration (p. 21), but will highlight a malfunctioning logger or faulty probes
and thus avoid a wasted profile run.
Do one of the following:
• With a full set of thermocouples attached to the logger, and the logger
connected to a PC running Insight, open the Logger Reset dialog (p. 40)
or the Diagnostic section of the Communications Setup dialog (p. 16); this
shows current probe temperatures – or . . .
• Set up the system as if to monitor a profile run using hardwired telemetry
(see p. 51 for details), and note the temperatures registered by the
thermocouples as they are displayed in Insight – or . . .
• To test the thermocouples alone, use a digital thermometer (of a type to
match the thermocouple type) and attach it to each thermocouple in turn.
62
Troubleshooting
FOOD TR ACK ER
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