HEIDENHAIN PROFINET - Manual (Page 17)

Installation
17
2.3 Shielding concept of the encoder
Automation systems in an industrial environment are subjected to
high levels of electromagnetic disturbance. Switching large elec-
trical loads creates high interference levels that can be picked up
in various ways by electronic devices with detrimental effects.
Even under such conditions, electric components within an auto-
mation system must still guarantee a continuous, uninterrupted
function.
The electromagnetic compatibility (EMC) of the entire plant must
be ensured by using suitably designed components and assem-
bling them correctly to make up the system. Data cabling is con-
sidered as a passive system and cannot be tested for EMC com-
pliance individually. Nevertheless, cabling and connection ele-
ments for PROFINET supports compliance with devices require-
ments by providing a high-quality, comprehensive shielding con-
cept.
To achieve the highest possible noise immunity and resistance
against other EMC related disturbances the bus and power supply
cables shall always be shielded. The screen should be connected
to ground on both ends of the cable. In certain cases compensa-
tion current might flow over the screen.
2.4 MAC-address
PROFINET IO field devices are addressed using MAC addresses
and IP addresses. All field devices have a unique MAC address.
The MAC address is constituted by a 6 byte Ethernet address for
each individual station and is unique worldwide. The MAC address
consists of two parts, the first 3 bytes represents the manufac-
turer-specific ID and the last 3 bytes represents a consecutive
number. The MAC address of the encoder is printed on the en-
coder label for commissioning purposes.