<inter-supply-con-lab-test>
The requirements on interferences by conduction in power supply conductions (<inter-supply-con>) are described for one (or possibly more) vehicle network voltage(s) by means of interference strength tests.
During an interference strength test, the behaviour of a DUT is tested by submitting the sample to a test pulse. Regarding interference strength test, the following specifications can be made.
 
Test pulse
The test pulse can be defined including all corresponding parameter values (...t1 to ... td). (as given in the definition,Representation example for test pulses for a 12 V vehicle network (according to DIN 40839 part 1).).
 
Severity level and correlated peak voltage for the test pulse
Severity levels, defined in Determination of severity levels for test pulses by means of pulse amplitudes according to DIN 40839 part 1 can be chosen. The specification of the severity level will only be required in case of standardized test pulses.
 
Test voltage
Vehicle network voltage applied during the test. Only defined if it deviates from the standard test voltage.
 
Internal resistance of the generator Ri
Internal resistance of the interference source
 
Minimum test amount
The minimum test amount is defined by the number of test pulses or by the duration of the test.
 
Intervals between test pulses
The intervals between test pulses have to be defined only for those test pulses for which there are not given any specifications in the standard. This is especially true for test pulse 5.
 
Interference source
The test device which generates the test pulse.
 
Operating state
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, they can be grouped.
 
Function state
The assignment of a function state to the test is accomplished by a code letter (A...E).
 
Fault description
The failure mode of the system will be described in textual form, in addition to the function state (if it is not equal to A).
 
Additional specifications
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.
The content of interference strength tests is not established in an (inter-)national standard. Apart from the test pulses 1 to 5, descriptions concerning interferences by conduction in power supply conductions (<inter-supply-con>) can be filed either in a user-defined way or according to in-house standards.
This includes, e.g., the test of the central load-dump protection with a characteristic that differs from test pulse 5, or the definition of the behaviour in case of a determined voltage characteristic in the power supply conductions.
The voltage characteristic describes the robustness of the system/the component against defined voltage changes, which may arise due to the failure of a generator or a defective vehicle battery. The voltage characteristic can be defined in form of a text or a graphic.
Figure 31: Structure of laboratory test
Example for content:

Representation example for interference strength requirements: concerning interferences by conduction in power supply conductions, test pulse 1
Denomination
Abbreviation
<short-name>
Min
<min>
Type
<typ>
Max
<max>
Abs <abs>
Tolerance
<tol>
Unit
<unit>
 
Severity level
       
4
     
Peak voltage
Us
     
-100
 
V
 
Test- spg.
Up
     
13.5
 
V
 
Internal resistance of generator
Ri
     
10
 
Ohm
 
Minimum test amount
       
30000
     
Intervals between test pulses
               
Interference source: test pulse generator NSG 500C
Operating state : switched on
Function state: A
Fault description: no fault
Additional specifications: Pulse generated by switching off inductive charges.

Definition test pulse 1
Denomination
Abbreviation
<short-name>
Min
<min>
Type
<typ>
Max
<max>
Abs <abs>
Tolerance
<tol>
Unit
<unit>
 
Intervals between pulses
t1
0.5
 
5
   
s
 
Duration of individual interference
t2
     
200
 
ms
 
Recovery time, duration between interference end and interference start
t3
     
100
 
µs
 
Pulse rise time
tr
     
1
 
ms
 
Pulse duration
td
     
2
 
ms
 
Test pulse: 2
...(Description as for test pulse 1)
Definition of the test pulse
A test pulse is described by a curve which is characterized by specific parameters. The shape of the curve depends on the vehicle network voltage.
According to [DIN 40 839-1;DIN 40 839-1;;all;]5 different test pulses (test pulse forms) are described with the help of corresponding parameter values which additionally depend on the vehicle network voltage:
1.
 
Pulse generated by disconnecting inductive loads.
2.
 
Pulse generated by direct current motors when disconnecting.
3.
 
Pulse generated by switching. There is a difference between 3a (negative peak voltage) and 3b (positive peak voltage)
4.
 
Pulse generated by closing the starter circuit in combustion engines. The ripple produced by the revolutions of the starter is not considered.
5.
 
Pulse generated, among other facts, by disconnecting the battery when the generator produces charge current (battery charge current disconnection pulse).

Representation example for test pulses for a 12 V vehicle network (according to DIN 40839 part 1)
test pulse
Ua
t1
t2
t3
t4
t5
t6
t7
t8
tf
tr
td
 
V
s
ms
µs
ms
ms
ms
ms
s
ms
ms
ms
1
 
0,5-5
200
µ100
           
1µs
2
2
 
0,5-5
200
             
1µs
0.05
3a
 
100µs
   
10
90
       
5ns
0.1µs
3b
 
100µs
   
10
90
       
5ns
0.1µs
4
-2.5
         
15
50
0.5-20
100
5
 
5
                   
0.1-10
40-400
Significance of parameters:
t1: Interval between pulses
t2: Duration of single interference
t3: Recovery time, duration between end of interference and beginning of interference
t4: Duration of switching burst
t5: Recovery time
t6: Duration of peak voltage drop Us
t7: Rise time from Us to Ua
t8: Duration of Ua
tf: Rise time operation voltage
tr: Pulse rise time
td: Duration of pulse
Ua: Voltage drop after transient state with reference to test voltage Up
Not all given parameters are used for the description of a test pulse.
Further user-defined or in-house standard specific test pulses can be given.
Definition of the severity level
The severity level determines the peak voltage Us of the test pulse.
According to DIN 40 839-1the following severity levels are defined:

Determination of severity levels for test pulses by means of pulse amplitudes according to DIN 40839 part 1
Test pulse
Pulse amplitude U s in volts
at severity level
(for vehicle network voltage of 12/24V)
 
I
II
III
IV
1
-25/-50
- 50/-100
- 75/-150
-100/-200
2
+ 25
+ 50
+ 75
+ 100
3a
-25/-35
-50/-70
-100/-140
-150/-200
3b
+25/35
+50/70
+75/140
+100/200
4
-4/-5
-5/-10
-6/-14
-7/-16
5
+26,5/70
+46,5/113
+66,5/156
+86,5/200
The peak voltage depends on the severity level and on the vehicle network voltage. Further user-defined or in-house standard specific severity levels with corresponding voltages U s can be defined for given test pulses.