Festo SFC-LAC CO Series, Manual, Page: 64 / 328

3. Installation
3−18
Festo P.BE−SFC−LAC−CO−EN en 0708NH
3.7.3 Bus power supply
Bus supply With external power supply to the field bus node of the
SFC−LAC avoid excessive distances between the bus power
supply and the SFC−LAC.
Caution
·
Make sure the polarity is correct when you connect the
field bus interface and the power supply for the bus
interface.
·
Connect the screening/shield.
·
With external voltage supply (see Tab.3/7):
Protect the voltage supply to the bus interface exter
nally, according to the number of stations on the bus.
Note
Bus slaves have different tolerances in respect of the
interface supply, depending on the manufacturer. Note this
when planning the bus length and placing the power unit.
For the SFC−LAC the following tolerance applies to the bus
interface supply (pin 9 on the Sub−D plug):
V
max
= 30.0 V
V
min
= 11.0 V
Recommendation:
Place the power unit approximately in the centre of the bus.