dataTaker CANgate, Руководство пользователя

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UM-0086-A2
CANgate User’s Manual Page 9
CAN/GPS/Power Connections
The supplied terminal adapter plug (DE9 male to 9-way terminal block) provides convenient screw terminal connections to
the CAN/GPS/POWER connector. Alternatively, a custom cable can be made up using a conventional DE9 plug.
A typical wiring configuration is shown below:
Diagnostic connector and GPS wiring diagram
Note A vehicle with an SAE J1962 diagnostic connector may not necessarily use a CAN network. If CAN is not used then the
indicated pins will either be not connected or in some applications may have a different function. Ensure that the vehicle does
actually use high speed CAN before connecting CANgate to the diagnostic connector.
CAN Bus Type and Termination
The CAN protocol can operate over a number of different physical layers . A physical layer is a specification defining the low
level electrical characteristics of the network, eg. allowable bit rates, voltage levels, cable type and so on.
It is important to note that CANgate only supports the
high speed CAN physical layer, as defined in ISO 11898-2 / SAE
J2284. This is by far the most widely used physical layer. The important characteristics of this standard are:

two wire, 5V differential signalling

bit rate 10kbps – 1Mbps

twisted pair cable, 120 Ω characteristic impedance
A high speed CAN network is required to have a linear topology. There is a single twisted pair "backbone" cable which can
be up to 40m long. Electronic control units (ECUs) are then connected to the bus using short
stub connections (max length
0.3m). (These limits are for 1Mbps operation and can be increased somewhat for lower bit rates.)
At each end of the bus, correct
termination is required. This typically consists of a resistor (wired across the two bus lines)
that matches the impedance of the cable (ie. 120 Ω ). The termination resistance provides the correct DC load for the CAN
output drivers, and minimises signal "reflections", which can distort the CAN signals and cause errors.
DE9 male
1
J1850+ – 2
3
CHAS GND – 4
SIG GND – 5
CAN HI – 6
ISO 9141 K – 7
8
9
J1850- – 10
11
12
13
CAN LO – 14
ISO 9141 L – 15
BATTERY – 16
Vehicle
Diagnostic
Connector
(SAE J1962)
1 – 5V out
2 – GND
3 – CAN1 HI
4 – GPS RXD
5 – CAN1 LO
6 – CAN2 HI
7 – CAN2 LO
8 – GPS TXD
9 – POWER
SAE J1962 male
GPS
CANgate
RXD
TXD
GND
Power
Connector to suit
GPS unit