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An interference emission is an interference emitted by the DUT onto the artificial network. In order to evaluate the emission of interferences by equipment in the laboratory, the DUT is connected to an artificial network, and put into operation. The following specifications can be given for an interference emission test.
| | Test pulse
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| | Severity level and corresponding peak voltage for the test pulse
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| | Test voltage ( <test-volt>)
Vehicle network voltage applied during the test. It will only be defined if it deviates from the standard test voltage.
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| | Equivalent resistance R S ( <substitute-res>)
The compensating resistance simulates the direct current resistance of consumers which cannot be switched off in the vehicle network.
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| | Operating state ( <oper-mode-refs>)
The operating state defines the state of the system at which the test is performed. If the test is to be performed with various operating states, these can be grouped.
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| | Additional specifications ( <add-info>)
Apart from the a.m. specifications, it is always possible to give additional specifications for a test. These include, e.g., a test temperature which differs from general specifications, the test set-up and further specifications which have not been defined yet.
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Figure 39: Structure of a laboratory test
Example for content:
Test pulse: 1
Requirement examples for interference emissions
Denomination
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Abbreviation
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Min
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Type
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Max
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Abs
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Tolerance
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Unit
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Severity level
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4
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Peak voltage
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Us
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-30
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V
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Test voltage
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UP
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12
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V
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Equivalent resistance
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RS
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40
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W
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Operating state : Switched on
Additional specifications:
Pulse which rises when switching off inductive loads.
Definition test pulse 1
Denomination
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Abbreviation
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Min
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Type
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Max
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Abs
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Tolerance
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Unit
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Pulse rise time
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tr
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1
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ms
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Pulse duration
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td
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2
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ms
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Definition of test pulses
Test pulses for the description of the interference emission according to DIN 40839 part 1
Test pulse
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tr
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td
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Unit
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µs
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ms
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E1
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1
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2
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E2
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1
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0.2
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E3
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0,05
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-
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E4
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E5
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400
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new
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Apart from the pulses E1 to E5, not standardized pulses can be defined, too. Since for these pulse forms no parameters can be defined yet, the description of theses pulses can be given in textual or in graphical form.
The characteristic test pulses are subdivided into interference emission grades via the pulse amplitude Us.
Determination of interferences emission grades for characteristic pulses via admissible pulse amplitudes according to DIN 40839 part 1
Characteristic pulses
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Admissible pulse amplitude U s in volts
at interference emission grade
(for 12/24V vehicle network voltage)
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IV
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III
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II
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I
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Pulse E1
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-100 /-200
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-75/-150
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-50/-100
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-25/-50
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Pulse E2
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+100
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+ 75
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+ 50
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+ 25
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Pulse E3 (a)
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-150/-200
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-110/-140
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-75/-70
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-40/-35
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Pulse E3 (b)
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+ 100
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+ 75
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+ 50
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+25
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Pulse E5
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+120/200
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+80/150
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+50/100
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+35/70
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The severity levels depend on the vehicle network voltage. Further user-defined or in-house standard specific severity levels with corresponding voltages U s can be defined to given test pulses.
Apart from the pulse-shaped interference emission, a continuous interference emission can be defined, too. Generator ripple counts among these emissions. The interference emission of the generator ripple defines the max. admissible disturbance of the vehicle network by the generator. This is only required in case of the generators. In order to obtain reproducible results, the test installation should be described by the conduction lengths, the conduction cross sections, the generator revolutions, the generator outputs, the load resistance, the charge current, the battery type and the state of the battery. Within this test, the parameters load, range of revolutions, generator output etc. are submitted to complex interaction. Thus at present it is not possible to define parameters for this test with simple means. The description for this requirement will be given in a textual or in a graphical way.
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