Installation

This section documents the installation requirements that shall be satisfied. The device can either be installed via the DB9 connector (supply and CAN-bus) or connected to a PC via USB. When using the device as an interface, both the DB9 and the USB are connected at the same time.

CAN-bus

The following requirements shall be satisfied when the logger is installed in a CAN-bus network.

ISO 11898-2

ISO 11898-2 defines the basic physical requirements of a high-speed CAN-bus network. Some of these are listed below:

  • Max line length (determined by bit-rate)

  • Line termination (120 Ω line termination at each end of data line)

  • Twisted data lines

  • Ground offsets in range -2 V to +7 V

Grounding

ISO 11898-2 tolerates some level of ground offset between nodes. To ensure the offset remains within range, it is recommended to use a single point ground reference for all nodes connected to the CAN-bus. This may require the ground wire to be carried along with data wires.

Stub length

It is recommended that the stub length is kept short. The stub length is defined as the length from the main data line wires to the connection point of the CAN-bus nodes.

Supply quality

The nominal voltage shall be kept within specifications at all times. The device is internally protected against low energy voltage events which can be expected as a result of supply wire noise, ESD and stub-wire inductance.

If the supply line is shared with inductive loads, care should be taken to ensure high energy voltage events do not reach the device. Automotive environments often include several potential electrical hazards, such as load dumps (disconnection of battery while charging), relay contacts, solenoids, alternator, fuel injectors etc. The internal protection circuitry of the CL1000 is not capable of handling high energy voltage events from such sources.

USB

The following requirements shall be satisfied when the device is connected through USB.

Grounding

Warning

Care should be taken to minimize the voltage difference between the USB and the DB9 connection if both are connected to the device at the same time. Differences in ground voltages can result in ground loops which can permanently damage the device. Desktop PCs are often grounded (care should be taken in this case) while laptops are often floating.