EM TEST
AN 200
Bedienungsanleitung
V 2.00
11 / 16
5.
Calibration / Measuring procedure
5.1.
Test load
For measuring the switch-off time the following test load (DUT) is specified in relevant standard references:
Test load =>
R (total) = 0,6
Ω
in series with
L (total) = 50
µ
H (1 kHz)
Both R and L also include the variations of the cable and
the structure. The parallel capacity which cannot be
avoided is approx. 50pF. The test must be constructed
such that the permanent current can be used at
maximum test voltage.
Figure 10 : Testlast
5.2.
Test voltage
According to the standards the switch-off times should be determined under varying test voltages.
Proposals: for Va :
U1 = 13.5V and U2 = 27V
Consequently constant currents of 22.5A or 45A must be considered. Due to the fact that the AN 200 is only
constructed for currents up to 25 A, calibration is only carried out with U1 = 13.5V. The resulting energy consumption
at the test load is approx. 300W.
5.3.
Switch-off times
The switch-off times are specified as follows, whereas fall time of the switch-off pulse is involved and measured
between 10 and 90% of the maximum amplitude:
ISO 7637 (old version < 1992)
tf = 200 ..... 400ns
ISO 7637 new and DIN 40839 part 1
tf = 300ns + 20%
5.4.
Blockdiagram
Rs
Source
AN 200
xx
xx
artificial
network
xx
cable length 0,5 m
EUT or
standard
load for
calibration
Figure 11 : Blockdiagram test setup
