Smooth Key; Set-Up Function (Instrument Configuration) - Chauvin Arnoux C.A 6549 Mode D'emploi

Remarks :
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During the procedure, pressing DISPLAY or turning the switch cancels the calculation in progress.
If the coefficient ∆T used for the calculation is not known, the instrument can calculate it in advance,
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using at least 3 stored measurements made at different temeperatures (cf. § 4.5.3)
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Detail concerning the calculation performed :
The insulation resistance varies with the measurement temeperature.
This dependence can be approximated by an exponential function :
where Rc : insulation resistance at reference temperature (Rc Temperature Reference)
RT : insulation resistance measured at T°C (Probe Temperature)
KT : coefficient at T°C defined as follows :
KT = (1/2) * ((Rc Temperature Reference-T) / ∆T)
T : estimated temperature at time of measurement (Probe Temperature)
∆T :
temperature difference for which the insulation is divided by 2.
Rc Temperature Reference :
reference temperature to which the measurement is referred.

6 / SMOOTH KEY

4.4
n
The SMOOTH secondary function activates / deactivates an insulation measurement digital filter. It
affects only the display (which is smoothed), not the measurements.
This function is useful if the insulation values displayed are very unstable.
The filter is calculated as follows:
RSMOOTH = RSMOOTH + (R – RSMOOTH) / N
Since N is set to 20, the time constant of this filter is approximately 20 seconds.
4.5

SET-UP FUNCTION (INSTRUMENT CONFIGURATION)

This function, located on the rotary switch, can be used to change the configuration of the instrument by
accessing directly the parameters to be modified.
Turning the rotary switch to SET-UP gives you access to the menu of all modifiable parameters. Select
the parameter to be modified and its value using the 4,3,5 and 6 keys.
4.5.1 SET-UP MENU
Rc = KT * RT
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