Specifications

B-5

B Buep 19-Expander driver

Notes concerning the connection of the PCS to a PLC:

• Connect the cable screening to the central common of the control

cabinet.

• Ensure appropriate chassis groundings with regard to the PCS housi-

ng on the one hand and the PLC bus board on the other. Remember

that a copper grounding strip, due to its large surface, ensures a

considerably higher RF conductivity than normal stranded intercon-

necting wire.

• Avoid, as far as possible, high frequency interferences, because

damping is very difficult in this case. The progr. contr. and the PCS

are electrically isolated by optocouplers, but this isolation is not

effective in case of high-speed transients, because optocouplers

feature a coupling capacitance (although it is very low).

• Ensure clear supply voltage reference points. To facilitate this, the

power supply is potential-free.

• If the supply voltage is influenced by high interferences, use a sepa-

rate power supply for the PCS (24 V, 10 VA). It should be equipped

with appropriate noise filters. In this case, 0 Volt can directly be

connected to protective earth at the PCS.

• Ensure a minimum distance of 200 mm between noise sources and

the PCS/the communication cable. This especially concerns inductors

and frequency converters.

• Please take care that the serial data lines are covered completely (if

possible) by the shield. Use a metallized connector hood at PCS as

well as at the progr. contr. side and ensure a highly conductive

connection between the connector hood and the shield. Please notice

that grounding on both sides may require an equipotential bonding

conductor with a cross section of 10 times that of the shield. This is

especially important, if the PCS and the progr. contr. are not con-

nected to the same common point (if they are for example installed

in different control cabinets). This is necessary to prevent equalizing

currents on the cable shield.