Alarm Button - AEMC 6550 User Manual

Use the ◄ ►▲▼ arrow buttons to enter the various parameters:
■ Air Temperature: the ambient temperature (optional).
■ Humidity: the ambient relative humidity (optional).
■ Probe Temperature: the temperature of the device tested. If it has not warmed up during the
measurement, it is equal to the ambient temperature.
■
Rc Reference Temperature: the temperature to which the measured resistance will be referred.
■
∆T for R/2: the temperature variation, known or estimated, sufficient to halve the insulation resistance.
To facilitate the programming, the instrument proposes default values.
The instrument then displays the insulation resistance referred to the reference temperature.
If coefficient ∆T for R/2 is not known, it can be calculated from a minimum of 3 measurements made on the
same device at different temperatures.
Detail concerning the calculation performed:
The insulation resistance varies with the measurement temperature. This dependence can be approximated by
an exponential function:
Rc = Kt * Rt
where Rc: insulation resistance referred to 40°C
Rt: insulation resistance measured at temperature T
Kt: coefficient defined as follows:
Kt = (1/2) ^ ((40 - T)/∆T)
where ∆T: temperature difference at which the insulation resistance is halved

2.4.2 ALARM Button

Press the ALARM button to enable the alarm defined using the CONFIG button (see 2.4.3) or in
SET-UP (see § 3.4). The ALARM symbol is then displayed.
If the measurement is less than the alarm threshold, the instrument indicates this by blinking the
ALARM symbol on the display and emitting an audible signal.
Press the ALARM button again to disable the alarm; the ALARM symbol disappears from the
display.
ALARM
10
Shop for AEMC products online at:
TEMPERATURE
Air Temperature
Humidity
Probe Temperature
Rc Reference Temperature
∆T for R/2
R measured
Rc at 40 °C
ShopAEMC
www.
23 °C
40%
23 °C
40 °C
10 °C
5.00 GΩ
1.529 GΩ
Megohmmeter Models 6550/6555
.ca 1.877.766.5412