Model 421504 Version 1.9 December 2004
6
Operation
Connecting RTD Probes
1. This meter uses 3-wire RTD probes (available through Extech Instruments). Insert one
or two RTD probes to the top of the meter. The meter is supplied with two RTD probe
connectors.
2. When the meter is turned on, the temperature readings will appear on the LCD display.
3. If a probe is not inserted, improperly connected, or is malfunctioning, all dashes "------"
will appear in the temperature display area.
Meter Power
1. Ensure that a fresh 9V battery is properly installed in the meter.
2. The POWER button is used to turn the meter ON or OFF.
3. If the low battery indicator appears on the display, change the 9V battery.
RTD type selection
1. Select the RTD type (alpha curve 3850 or 3926) that is connected to the T1 terminal
using the Pt385/3926 button (the button with the number ‘5’ overlay).
2. Select the RTD type (alpha = 3850 or 3926) that is connected to the T2 terminal using
the Pt385/3926 button (the button with the number ‘0’ overlay).
3. The LCD display indicates which alpha curve is selected.
Note: Alpha curve 385 is the DIN/IEC worldwide current standard while Alpha 3926 is
an older standard. If unsure, check with the Probe manufacturer. If still in doubt, use
the 385 selection. The meter remembers the selection when powered OFF.
Selecting T1, T2, and T1-T2 Displays
1. Use the T1 T2 T1-T2 button (button with the number ‘4’ overlay) to select views for the
Primary display. RTD 1 (T1), RTD 2 (T2) or the difference between the two (T1-T2) can
be shown in the Primary display area.
2. Use the T1 T2 T1-T2 button (button with the ‘-’ overlay) to select views for the
Secondary display. RTD 1 (T1), RTD 2 (T2) or the difference between the two (T1-T2)
can be shown in the Secondary display area.
3. The LCD displays T1, T2, or T1-T2 icons for both Primary and Secondary displays for
convenience.
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