Seaward IRT 1557 - Manual (Page 14)

IRT1557
Operating Instructions
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5.4.5 Press and hold the TEST button. A single beep
indicates a stable reading. The primary display
shows the measured resistance. If the measured
resistance is greater than 20 Ω, >20 Ω is
displayed.
5.4.6 After releasing the TEST button, reverse the
connections of Red (+) and the Black (-) probes
to reverse the polarity of the test current and
repeat the measurement.
5.4.7 The measured value should be the same as the
previous value. This test is useful to detect
corroded connections, which can cause different
readings for both polarities.
5.5 Measuring resistance
Always ensure that the circuit under test is
isolated before attempting to make a resistance
measurement.
5.5.1 Rotate the rotary switch until the resistance test is
selected.
5.5.2 Connect the test probes to the circuit to be
measured.
If a voltage greater than 30V is present at the
test probes the buzzer will sound, the warning
icon is displayed and the measured voltage is
displayed. Resistance measurement is inhibited
until the voltage is removed.
5.5.3 Press and hold the TEST button. The primary
display shows the measured resistance. If the
measured value is less than 30 ohms the
continuity buzzer will sound. If the measured
resistance is greater than 2000 Ω, >2000 Ω is
displayed.