Error Indicators; Broken Probe; Low Battery; Instrument Malfunction - Welch Allyn Diatek 600 Technical Manual

Technical Manual

Error Indicators

Probe Position Error—During normal mode operation the visual probe position error indicator will be
displayed as long as tissue contact is broken and the probe temperature is falling. This display
indicates that a condition exists which may not provide accurate temperatures. The error indicator does
not affect the temperature taking cycle in any way.
No temperatures may be taken when any of the following error conditions exist:

Broken Probe

A probe error will be indicated if the probe circuit is open (below 10° greater than 60,000 ohms) or
shorted (above 150° F or less than 2,000 ohms). The horn sounds a double beep repeating every 10
seconds with the probe error display flashing. The unit will shut off automatically after 5 minutes of
error indication. The error will be detected any time during predict or monitor mode operation.

Low Battery

A low battery condition exists when the battery voltage drops to approximately 3.0 volts. A low battery
indication may occur any time during monitor mode operations but only at the start of a predict mode
temperature. If a low battery condition exists prior to starting the pulse timer, the low battery error will
be displayed when the timer is started and any normal mode temperature in progress will abort at that
time. The low battery error displays a flashing symbol with a double horn beep sounding every 10
seconds. The unit will shut off automatically after five minutes of error indication.

Instrument Malfunction

A malfunction error will be indicated if either the internal calibration self-test or the internal
microprocessor self-test fails. The malfunction indicator flashes with a double horn beep sounding
every 10 seconds. The thermometer will automatically shut off after five minutes of error indication.

Self-Tests

Battery Installation Display Test

Immediately following the installation of batteries into the Model 600, a one time only display test is
provided. All segments of the entire display (including the pulse timer and error indicators) are
sequentially lighted for 0.4 seconds. The entire test takes 25 seconds and must occur prior to starting
any temperature or timer functions.

Thermometer Startup Tests

Display and Horn Test

Each time the probe is removed from its holder all display segments (except for the pulse timer) are
lighted for 6 seconds as a visual display test. During the display test the horn sounds for 0.1 second.

Internal Calibration Test

During each thermometer startup display test a precision resistor is used to check the thermometer
calibration at 100.5°F (38.1°C). A failure of the thermometer to measure the calibration resistor within
±0.2°F will cause the malfunction error to flash, the horn will sound with a double beep every 10
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