Baldor MN1903 Can Connections, Cable length Maximum bit Resistance Conductor Rate Area

4.6 CAN Connections

5 & 6 1 & 2

7 & 8 3 & 4

CAN (Controller Area Network) is a 1Mb/s local area network.

Two CAN channels are supported by NextMove PCI - CANopen and Baldor CAN. Access to both channels is configured by a 10-pin 2mm pin header, J11, mounted along the top edge of the NextMove PCI card. Jumpers link pin pairs 1 and 2, 3 and 4, 5 and 6, 7 and 8. These jumpers route the CAN signals to the breakout module and only need to be removed if you are connecting a CAN Bracket card.

CAUTION: Pins 9 and 10 must NOT be connected together. Doing so will short-circuit the PC’s 5V power supply.

The NextMove PCI can communicate with I/O expansion modules or other MintMT 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 500m (1640ft) 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 125Kbit/s although higher rates up to 1000Kbit/s 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.

Up to 63 mixed type Baldor CAN peripherals may be connected to the NextMove PCI Baldor CAN network using the CAL protocol, with the limitation that only 4 enabled keypads are allowed at one time. In addition, a number of CANopen nodes can be connected simultaneously to the CANopen network.

Terminators are provided on the breakout module for each CAN channel. These are connected by jumpers J7 (Baldor CAN) and J8 (CANopen).

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

4-20 Input / Output MN1903