Baumer BA_DSRT_22DJ - Handbuch (Seite 9)

Manual_CANopen_StrainLink_EN_V3_05.doc 9/65 Baumer
22.07.11/dam Frauenfeld, Switzerland
3.3 EMC-compatible wiring
EMC (electromagnetic compatibility) is the ability of a device to operate without errors in a specified
electromagnetic environment without affecting the environment in an impermissible way.
All CANopen strain links meet these requirements because all sensors have been tested for compliance with
the legally prescribed limits (industrial standard).
3.3.1 Grounding inactive metal parts
All inactive metal parts must be bonded over a wide area and via a low impedance path (grounding). This
action ensures that there is a uniform reference potential for all elements of the system.
The CANopen strain links are grounded by way of the four mounting screws.
3.3.2 Shielding lines
The shield should be grounded, if possible, at both ends using an EMC-compatible shield connection.
3.4 Specification of the CAN lines
The cable that you use to connect the bus users to the CAN bus must comply with the ISO 11898 standard.
Consequently, the lines must possess the following electrical characteristics:
Specification of the CAN lines
Bus system total length < 300 m < 1,000 m
Cable type LIYCY 2 x 2 x 0.5 mm²
(shielded twisted pair) CYPIMF 2 x 2 x 0.5 mm²
(shielded twisted pair)
Line resistance ≤ 40 Ohm/km ≤ 40 Ohm/km
Capacitance ≤ 130 nF/km ≤ 60 nF/km
Connection Pair 1 (white/brown): CAN-GND and +Vs
Pair 2 (green/yellow): CAN-HIGH and CAN-LOW
•
Only use lines that have an additional pair of conductors for CAN-GND.
•
Noise-free bus operation is only possible with a correctly connected CAN-GND.
Connect the bus termination resistors
A 120 ohm termination resistor must be connected at the physical beginning and at the physical end of the
bus system.