Baldor MN1274 06/2001 installation manual B CAN B B.1 Outline, B.1.1 MintDrive capabilities

B CAN B

B.1 Outline

This section provides an introduction to the CAN (Controller Area Network) peripherals and how these are configured to operate with the MintDrive.

B.1.1 MintDrive capabilities

The MintDrive can communicate with I/O expansion modules or other Mint v4 controllers via CAN, and is compatible with DS-301, version 4 (Application Layer and Communication Profile) and mandatory sections of DS-401, version 2 (Device Profile for Generic I/O modules). Some parts of DS-403, version 1 (Device Profile for Human Machine Interfaces) are also supported. When connecting third party devices please contact Baldor if you are unsure about compatibility.

CAN offers serial communications over a two wire twisted pair cable up to a maximum of 1640ft (500m) in length, and offers very high communication reliability in an industrial environment; the probability of an undetected error is 4.7x10-11. The default transmission rate is 125Kbaud although higher rates up to 1000Kbaud can be selected.

CAN is optimized for the transmission of small data packets and therefore offers fast update of I/O devices (peripheral devices) connected to the bus. Several CAN peripheral devices may be attached to the same controller via the CAN link using the CAL protocol. Up to 63 mixed type CAN peripherals may be connected to the MintDrive CAN network, with the limitation that only 4 enabled keypads are allowed at one time.

On the MintDrive, connection to the CAN networks are made using a 9-pin male D-type connector for CAN bus channel 1 (CANopen) and a shielded RJ45 type connector for CAN bus channel 2 (Baldor CAN). Both CAN channels are isolated. When MintDrive is at the end of a CAN network, the terminator for that channel must be activated. The terminators are activated by setting the DIP switch on the front panel to ON. Each CAN channel has its own DIP switch and terminator.

A very low error rate over CAN can only be achieved with a suitable wiring scheme, so the following points should be observed:

HCAN must be connected via twisted pair cabling to reduce RF emissions and provide immunity to conducted interference. The connection arrangement is normally a simple multi-point drop. The CAN cables should have a characteristic impedance of 120Ω and a delay of 5ns/m. Other characteristics depend upon the length of the cabling:

Cable length	Maximum bit rate	Resistance	Conductor area
0ft ~ 131ft (0m ~ 40m)	1000Kbaud	<70mΩ/m	0.25-0.34mm2
131ft ~ 984ft (40m ~ 300m)	500Kbaud	<60mΩ/m	0.34-0.60mm2
984ft ~ 1968ft (300m ~ 600m)	100Kbaud	<40mΩ/m	0.50-0.60mm2
1968ft ~ 3280ft (600m ~ 1000m)	50Kbaud	<26mΩ/m	0.75-0.80mm2

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