
Appendix
S7-300 Programmable Controller Hardware and Installation
11-6
A5E00105492-01
11.2.2
Five basic rules for insuring EMC
If you conform with theses five basic rules ...
you can insure EMC in many cases!
Rule 1: Large-area grounding
When you install the automation equipment, make sure that surfaces of inactive
metal parts are well bonded to chassis ground (see the following sections).
•
Bond all passive metal parts to chassis ground, ensuring large area and low-
impedance contact.
•
When using screw connections on varnished or anodized metal parts, support
contact with special contact washers or remove the protective insulating finish
on the points of contact.
•
Wherever possible, avoid the use of aluminum parts for ground bonding.
Aluminum is highly corrosive and is therefore less suitable for ground bonding.
•
Create a central connection between chassis ground and the equipotential
busbar/protective conductor system.
Rule 2: Proper cable routing
Ensure proper cable routing when you wire your system (see the section below on
Indoor/outdoor cable routing).
•
Sort your wiring system into groups (high-voltage/power supply/signal/data
cables).
•
Always route high-voltage, signal or data cables through separated ducts or in
separate bundles.
•
Install the signal and data cables as close as possible to grounded surfaces
(e.g. supporting beans, metal rails, steel cabinet walls ).
Rule 3: Mounting the cable shielding
Take care that all cable shielding is properly fastened (refer to the section on
Shielding of cables).
•
Always use shielded data cable. Always connect both ends of the shielding to
ground on a large area.
•
Analog cables must always be shielded. For the transmission of low-amplitude
signals it might prove to be more efficient to have only one side of the shielding
connected to ground.
•
Directly behind the cable entry in the cabinet or enclosure, terminate the
shielding on a large area of the shielding/protective ground busbar and fasten it
with the help of a cable clamp. Then, route the cable to the module; however,
do not connect the shielding once again to ground in this place.
•
Connections between the shielding/protective ground busbar and the
cabinet/enclosure must be of a low impedance.
•
Always install shielded data cables in metal/metallized connector housings.
Содержание Simatic S7-300
Страница 10: ...Contents S7 300 Programmable Controller Hardware and Installation x A5E00105492 01 ...
Страница 16: ...Preface S7 300 Programmable Controller Hardware and Installation 1 6 A5E00105492 01 ...
Страница 22: ...Quick Guide S7 300 Programmable Controller Hardware and Installation 2 6 A5E00105492 01 ...
Страница 28: ...Product overview S7 300 Programmable Controller Hardware and Installation 3 6 A5E00105492 01 ...
Страница 74: ...Configuring S7 300 Programmable Controller Hardware and Installation 4 46 A5E00105492 01 ...
Страница 102: ...Wiring S7 300 Programmable Controller Hardware and Installation 6 18 A5E00105492 01 ...
Страница 148: ...Commissioning S7 300 Programmable Controller Hardware and Installation 8 36 A5E00105492 01 ...
Страница 236: ...Glossary S7 300 Programmable Controller Hardware and Installation 12 16 A5E00105492 01 ...