Instruction Manual

3. Installation

3−17

Festo P.BE−GDCP−SFC−LACI−PB−EN en 0812NH

3.7 Connecting the field bus

3.7.1 Field bus cable

Note

Faulty installations or high transmission rates may cause

data transmission errors as a result of signal reflections

and attenuations.

Transmission errors can be caused by:

 missing or incorrect terminating resistor

 incorrect screened connection.

 branches

 transmission over long distances.

 unsuitable cables.

Observe the cable specifications. Refer to the manual for

your control system for information on

the type of cable to

be used.

Note

If the SFC−LACI is installed in a machine on a movable

mounting, the field bus cable must be provided with strain

relief on the moving part of the machine. Please also

observe the relevant regulations in EN60204 part 1.

Use a twisted screened 2−core cable for the field bus in

accordance with PROFIBUS

specifications (EN 50170,

cabletype A):

Surge impedance: 135 ... 165  (3 ... 20 MHz)

Capacitance per unit length: < 30 nF/km

Loop resistance: < 110 /km

Core diameter: > 0.64 mm

Wire cross section: > 0.34 mm