Harness Design Process - from Idea to Manufacture

v 

volt 

vcc 

v 

5 

10k 

0.01 

10k 

ohm 

SABER 

100k 

position 

lm2904n_3 

100k 

m1 

m2 

vee 

vcc 

vcc 

1k 

m1 

m2 

m2 

m1 

100n 

pos 

dcmot 

out2 

neg 

shaft 

out1 

shaf t_ in 

) 

( 

m 

0.6 

0.4 

0.2 

0.0 

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 

20.0 

0.0 

-20.0 

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 

X6 5 

x124:2 

*req* power_supply:sw_1pno2.m 

windows_back:d9.p 




3451212X X7A 

X0 X5 power_supply:batt_pb_1_2.p 

x125:2 x125:1 x124:1 

Analogy 20.04.99 Joachim EL. PASS 

DRIVER 

D0U 12.03.99 

Initial 12.04.99 JL Simulation Connectors 20.03.99 Description Who Date TH FMEA 15.04.99 OPERATED Design Added Langenwalter 

added WINDOW WINDERS 

SIDE 

Seoul 2000 FISITA World Automotive Congress 

June 12-15, 2000, Seoul, Korea 

F2000A159 

Harness Design Process 

- from Idea to Manufacture 

Joachim Langenwalter 1) 

Thomas Heurung 2) 

1) Manager Transportation, Analogy Inc., Beaverton Oregon, USA 

2) Product Specialist Harness Design, Analogy GmbH, Munich, Germany 

Due to the requirement of cost and development time reduction all automotive OEM’s and suppliers need to increase their 

productivity. At the same time the number of electrical systems in a modern vehicle runs into hundreds, and the design and 

optimization of the wire-harness connecting all components together is becoming a significant design task. Optimizing the 

cost and the quality of the harness for satisfactory operation under a wide range of conditions is important to keep the 

vehicle cost competitive. The use of a simulation tool to help in wire sizing and test, tightly coupled to a dedicated harness 

design tool is getting indispensable for this task. 

The different components will be integrated together with the harness on a virtual platform. With this concept it is possible 

to perform functional tests or to do FMEA quite early in the design cycle. The paper will show the development process 

from the first functional schematics over the cabling diagram, down to the manufacturing data in a bundle drawing. 

Furthermore it will bridge the gap between 2D CAD and 3D Mechanical CAD. The design of a Power Window System 

will serve as an demonstrator for this new development flow. 

INTRODUCTION 

The key for an advanced development process is an 

integrated flow from the first idea down to manufacture. 

The flow starts from the first idea for a new function in the 

car (e.g. Steer by Wire), which can be selected from a 

functional database. From that a knowledge based tool 

places the subsystems automatically into a functional 

schematic. Now these components are connected together 

by wires (cable drawing). Many wires are bundled together 

in a bundle drawing from which the formboard drawing 

and manufacturing is driven. This whole process is tightly 

integrated to the in-house PDM system and the 3D CAD 

flow. 

FUNCTIONAL SCHEMATIC 

User 

Motor 

Spring for bounce back algorithem test 

To illustrate this approach a power window system will 

serve as an example (see figure 1). The functional 

schematic just links all the components in there logical 

order with ideal connections. It consist of a motor driving 

the window mechanics. The user can switch on the motor 

which drives the window mechanics. The revolutions of 

the motor shaft are counted by a hall sensor. If the 

frequency of these pulses are changed by a certain amount 

due to a hindrance, the software detects this and puts the 

motor into reverse mode. The current through the motor is 

measured by a shunt and amplified by a opamp and leads 

to a switch off when the block current is reached 

(closed/open position). 

CABLE SCHEMATIC. 

The Cable Drawing links all components in the actual 

layout. The nodes are now real wires with physical 

dimensions like area, color, variants etc.. 

DRIVER 

11 FDD FDP FPP BPP BDD 

SIDE 

Position 

Electronic 

Software 

Current 

Figure 1: Functional Schematic in SaberSketch 

Figure 2: Cable Drawing in SaberHarness 

1

ILS4 

bl 

* 

RS5 

RS5 

Lug 

* 

* 

* 

RS5 

RS5 

RS5 

RS5 

LS4 

hi 

LS4 

hi 

* 

* 

* 

* 

* 

* 

* 

* 

*op 

* t 

20 - 9 

Figure 2 shows the four switches for the car driver on 

the left, one switch for the passenger on the right and 

four relays for two window motors in the middle. The 

motors and relays for the rear windows are on a 

separate sheet, which is not shown here. The unused 

separate sheet and switches for the rear window can be 

filtered out when building only a two door car from 

the same platform (e.g. a coupe). The variants are 

selected and filtered from predefined customer lists 

and attached to every symbol, graphics and connector 

The connectors and their pinning is controlled by a 

connector manager. The 2D SaberHarness requires an 

engineer to design the electrical systems connectivity. 

It keeps track of how each subsystem interacts, what is 

comprised in each drawing (wires, connectors etc), 

variant information, layout details and basically 

everything needed to implement that function in a 

vehicle. Furthermore it controls all revisions and 

versions of the subsystems, with a tight integration of 

electrical, mechanical, cost and manufacturing data 

aimed at electrical systems and harness design. The 

cable drawing interfaces to the 3D CAD software 

(Catia E3D, ProCable etc.). The components and the 

linking wires are transferred into a neutral file format. 

The CAD tool now reads the cable and components 

file into its database. The cable designer places then 

the components into the car body and routes the 

bundles throughout the cable tunnels (see figure 3 

below). 

Figure 4: Power Window in Catia E3D 

Every step is synchronized with the PDM (Product 

Data Management) system, which drives all necessary 

documents for the manufacturing of a car, like bill of 

material, documentation, formboard ( see figure 5 ) 

and after-sales handbooks. 

A 

B 

0 1 2 3 4 

No dfd_spkr_2 

Matching 5 Pin Socket Connector - R series 

Assembly 

dfpr 

5 Pin Socket Connector - R series 

No 

Matching 

Assembly 

dfdr 


No 

Matching 

Assembly 

dfpf 


No 

Matching 

Assembly 

dfdf 


5 - 2 

A 

B 

C 

No 

Matching 

Assembly 

dfd_spkr_1 


4 - 0 

rly_df_2 

4 Pin Socket Connector - L series 

C 

D 

4 - 2 

df 

4 Pin Inline Socket Connector - IL series 

dfd2body 

*opt* 

D 

earth2 

*opt* 

4 - 0 

rly_df_1 

4 Pin Socket Connector - L series 

E 

E 

0 1 2 3 4 

Figure 5: Bundle Drawing of one Door in Saber- 

Bundle 

NOMINAL, MONTE-CARLO,SNEAK AND 

FMEA ANALYSIS 

Figure 3: 3D Cable Drawing 

When looking at the door in detail, the power window 

system is shown in figure 4. From the 3D MCAD tool 

the wire length, splice positions are back annotated 

into SaberHarness. After that all necessary information 

for a detailed analysis are collected together. 

Every new system needs several prototype iterations until 

it is fully functional and debugged, but development times 

are reduced more and more and the complexity of today’s 

vehicles is increased quite significantly at the same time. 

There is not enough time to run through enough real 

hardware prototypes. The solution is a Digital Mock UP. 

On a Virtual Prototype even more iterations in a shorter 

amount of time can be performed. In order to achieve this 

several virtual system tests are applied. The DMU is now 

analyzed under several operation conditions. Figure 3 

shows also the simulated position and the current of the 

window system versus time for nominal parameter values. 

The Figure 7 illustrates the spread of the results the 

window position versus time with tolerances on all 

sensitive components (e.g. Window Mechanics, Motor, 

Supply Voltage). 

2

X6 5 

20.04.99 Joachim EL. x124:2 

*req* power_supply:sw_1pno2.m 





3451212X7A 

X0 X5 power_supply:batt_pb_1_2.p 

12.03.99 

Initial 12.04.99 JL Simulation Connectors 20.03.99 Description Who Date x125:2 x125:1 x124:1 TH FMEA 15.04.99 OPERATED Design Added Langenwalter 

added WINDOW WINDERS 

0.5 

(m) : t(s) 

Window Position 

seconds, but the fuse is blown and the window is still 

closed. The increased mechanical friction fault in the 

fourth row lead to a high current in the fuse (6.29 [A]) and 

a partially open window after 5 seconds. 

0.4 

0.3 

0.2 

0.1 

0.0 

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 

t(s) 

Figure 7: Window Position vs. Time with Tolerances 

Finally the figure 8 outlines the possible fault areas in the 

power window cable diagram. The individual faults are 

defined by the component model developer (e.g. the 

supplier). The designer now integrates all these 

components together and applies the FMEA Analysis. The 

tool now finds all possible faults, e.g. short circuit of relay 

pin X7 to X7A or a sticking shaft of the motor, 

automatically. They are activated in sequence one after the 

other and the results are displayed either in the schematic 

or in an FMEA report (see figure 9). 

Analogy 

PASS 

DRIVER 

D0U 

11 FDD FDP FPP BPP BDD 

SIDE 

The Sneak Tool analysis if the expected function happens 

and the unexpected operation does not happen. The 

expected function is the opening and closing of the 

window, when activating the switches. An unexpected 

operation of the power window is a ground offset and the 

malfunction of the bounce back algorithm due to that 

( immediate window reversal), after 2 switches are set at 

the same time. A sneak path could be caused by some 

switch combination and detected by current reversals or 

design intent. A design intent is the reversal of the current 

in the relay switches in a power window in close mode 

compared to opening mode. The sneak analysis is pretty 

fast, because it requires only a initial point analysis and no 

time domain analysis. The switch combinations are set and 

then the current values and direction is calculated in one 

iteration. The Results are shown in the CAD tool or in an 

report, as shown below. 

S1 S2 S3 S4 Sneak 

0 0 0 0 

0 0 0 1 

0 0 1 0 

0 0 1 1 

0 1 0 0 

0 1 0 1 

0 1 1 0 

0 1 1 1 

1 0 0 0 

1 0 0 1 * 

1 0 1 0 * 

1 0 1 1 * 

1 1 0 0 

1 1 0 1 * 

1 1 1 0 * 

1 1 1 1 * 

Figure 10: Sneak Report 

Figure 8: Power Window with Fault Areas 

The Switch combination in the last row with all switches 

active (0 = neutal, 1 = window open) lead to a sneak in the 

power window, which had to be resolved. In this case the 

bounce back algorithm did not work correct, because of a 

ground offset. Therefore the bounce back sensor ground 

was separated from the motor ground. Another solution is 

the bounce back algorithm approach, as explained earlier 

in this paper, which does not require an extra sensor in the 

door frame. Therefore it does not cause a sneak path and it 

is also cheaper to manufacture. 

EMC 

Figure 9: FMEA report with functional Labels 

After the fault was activated the window switch was set to 

open the window. The short circuit between the two pins 

X7A and X7 of the relay ‘r1’ in line 3 of the FMEA report 

lead to a low current (12.43p [A] not shown here) after 2 

Finally a big challenge is the EMC (Electromagnetic 

Compatibility), which need to be analyzed for the system, 

subsystems and components. This is addressed in the 

European funded AutoEMC project which covers : 

• Crosstalk means the calculation of current and voltage 

along the wire, which influence each other under near 

field condition. The frequency range is limited by the 

3

sources inside the car and can be limited mostly to 0 

to 150MHz. 

• EMI (Electromagnetic Interference) respects the 

radiated field from the harness to the antenna and 

overcomes a frequency range from 0.1MHz to 150 

MHz. 

• EMS (Electromagnetic Susceptibility) considers the 

coupling between an external plane wave and the 

harness or an internal antenna (e.g. mobile phone) and 

the harness. Here the frequency range from 0.1MHz 

to1GHz / 4GHz 

The EMI and EMS is covered by the interface between a 

3D field solver in the frequency domain (PamEMC from 

ESI Group) and the network solver (Saber from Analogy 

Inc.). The Crosstalk was implemented by coupling the 2D 

FEM tool (Crypte from ESI Group) and the CAD / CAE 

tools SaberBundle / Saber. The figure 11 shows the typical 

simulation result of a EMI calculation. 

/3/ Automotive System Simulation, Power Window 

FMEA, SAE Dependability Practices TOPTEC; 1-2 

November 1999, Joachim Langenwalter, Analogy Europe, 

Thomas Heurung, Analogy GmbH 

/4/ ANALYSIS AND OPTIMISATION OF AUTO- 

MOTIVE WIRE HARNESSES, January 2000, Andrew R. 

G. Patterson, Analogy UK Ltd. 

/5/ www.analogy.com, Analogy Inc., Beaverton Oregon 

USA 

/6/ www.esi.fr, ESI Group, Paris France 

Figure 11: EMI calculation in PamEMC 

CONCLUSION 

It took 5 virtual iterations to design this example system of 

the power window within 4 weeks. Without an integrated 

design an analysis flow this would take several months, 

with ordering of components, assembly and hardware tests. 

A more complex and even more robust product is the key 

to success in the next generation, e.g. 42V Systems . It 

took over 30 years to debug our existing 14V systems, and 

create databooks and design rules for them. We do not 

have the time for those hardware iterations again. 

REFERENCES 

/1/ VDI Systemengineering in der KFZ-Entwicklung, Dec. 

1997, Wolfsburg, “Aufbau einer Integrationsplattform für 

physikalische Simulation”, Wolfsburg, M. Paulini, BMW 

AG, Dr. G. Triftshäuser, BMW AG, Dr. P. Willutzki, 

BMW AG, Joachim Langenwalter, Analogy Europe 

/2/ Mechatronics '98 in Skovde, Sweden, Sept. 9-11 1998, 

Hardware Oriented Modeling and System Identification: 

Breaking the Barrier between Design and Analysis, Mike 

Donnelly, Analogy, Inc., Beaverton, OR and Joachim 

Langenwalter, Analogy Europe 

4

Harness Design Process - from Idea to Manufacture

Create successful ePaper yourself

Delete template?

Save as template?