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CAN Bus Data Logging with MW100

Industry: Transportation R&D

Product: Yokogawa MW100 Data Acquisition System

Introduction

In the transportation industry, vehicle manufacturers perform

a wide range of performance and d ura bility tests on the

complex systems that comprise a modern vehicle. Test

parameters cover an equally wide range and incl ude an

extensive amount of temperature, pressure, flow, vibration,

speed and electrical parameter measurements. Of this,

temperature is perhaps the most common; a test vehicle can

be outfitted with dozens of thermocouple sensors attached to

virtually every area and major system of the vehicle.

The material and installation cost of sensor wire for these

tests is significant. Engineers and technicians look for ways

to reduce the complexity of their test systems and at the

same time improve the performance. A solution is cl early

needed to reduce the ever-increasing quantities of sensor

wiring.

Application

Provide a method to monitor and recor d large numbers of

sensor data on a vehicle that does not requir e a discreet

cable connection from each sensor to an i nput channel, thus

reducing the wiring costs. Utilize a serial data bus for this

connection that is also the integral control net work interface

for certain vehicle systems.

In some vehicle brands, a serial data bus called CAN

(Controller Area Network) is used to carry information

between certain vehicle control systems such as the engine

management, cruise control, and anti-lock brake systems.

Many of the data points that need to be monitored and

recorded during the vehicle test phase ma y be present on

the CAN bus. In addition, a dedicated CAN bus can be

implemented to carry test data only, or discrete sensor

values can be placed on an existing b us.

A vehicle test team will need a monitoring and recording

system that can interface directly to a CAN network where it

can receive the needed data in the form of CAN messages.

Ideally, the test system should be able to acquire both di gital

CAN message data, and traditional analog sensor inputs on

the same platform. It must have stand-alone data logging

capability (attach sensor wires, CAN connec tion) and run

with no PC connection, and include high capacity Compact

Flash media that can store many channels of data at fast

intervals for long time periods. It must also be compact and

portable and powered by 12-24VD C for in-vehicle

applications.

Solution

The new CAN Interface Module (model code MX118-CAN-

M30) for the MW100 allows the MW100 to be used in a

number of monitoring and dat a logging applications in

transportation industry product testing and development. In

automotive testing application s, temperature measurement is

by far the most common requirement for data acquisition. On

test vehicles and in test stands, dozens of thermocouples

are typically used to sense a wide range of temperature data

on many vehicle areas and systems that include:

• Under-hood- engine, coolin g system, HVAC, exhaust, and

induction systems

• Driveline- transmission, differential and brake systems

• Interior- HVAC ducts and passenger compartment

The traditional method of wiring many thermocouples to

discreet inputs on a data acquisition system is very wire and

labor intensive. An alternative method that reduces the

cabling requirements is CAN bus. With CAN bus, multiple

thermocouples and other ana log sensors can be wired to a

data acquisition module that measures each input and

outputs the data on a serial CAN interface. Using this

method, many thermocouple wire pairs can be red uced to a

single data cable.

The MW100 with the CAN interface module is the ideal

system for monitoring and recording the data traveling on the

CAN bus.

For an under-hood temperature measurement application,

thermocouple sensors can be attached to a thermoc ouple-to-

CAN converter module such as a CSM Thermo-Scan

MiniModul. This device can measure up to 8 thermocouples

(16 input models are available), and output the values on a

single data cable the di ameter of a pencil, allowing easy

pass through of the firewall to an on-board data acquisition

system.

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The MW100 provides its full range of

data logging and PC connectivity

functions to any stationary or portab le

test application that requires

monitoring and recording of CA N bus

message data. Combined with

hardware such as the CSM Thermo-

Scan modules, a large number of

analog signals can be condensed into

a single cable connectio n and quickly

and easily attached to an MW100

system for data logging.

The CAN interface module ca n be

combined with any combination of

standard MW100 I/O modules,

providing the user with a truly flexible

data acquisition/data logging system

that can handle a wide range of stationary and in-vehicle

testing applications.

A complete MW100 demonstration system with CAN

interface to a CSM thermocouple module is shown below.

Additional References:

For detailed product information and

specifications, see the following

documents:

• MW100 CAN Interface Module

Bulletin; 04M10B01-02E-A

• MW100 Bulletin; 04M10B01-01E

• MW100 General Specifications;

GS04M10B01-01E

Demo system power supply for the

CSM module (Both the CSM module

and the MW100 can be powered by

vehicle DC power in actual service)

MW100 CAN Interface Modu le

CSM Thermo-Scan MiniModul

measures up to 8 Type K T/Cs, and

outputs each channel o n the serial

CAN bus.