Public:Profibus Connection

Template:Infobox bms

1 Specification

• Max. 32 Stations for each Segments
• Max. 127 Stations at one Interface with the use of a repeater at each Segment
• Max lenght of loop
  • 12 MBit - 100m
  • 1.5 MBit - 200m (BMS Standard)
  • 500 kBit - 400m
• Termination Resistance ~220 Ohm (Both sides needs to be terminated -> ~110 Ohm total Resistance)

2 Topology

Compare if the installed devices are corresponding to the drawing. If differences appear, clarify what is correct and remark the differences. A busfault will occur, if the devices are not configured correct in the busconfiguration file. This can make the fault finding difficult, because you are looking for a hardwarefault in the buswiring, although “only” the config-file does not match the installed device.

3 Routing

• The path of the buscables must be according to the electrical drawings. If there are any differences update the drawings as required.
• Outside of cabinets, the profibus cable should be pulled through grounded metal conduits, not plastic conduit.
• In cable trays, the bus cables must be separated from power cables and especially converter driven motor cables.
• The ambient temperature must not be higher than 60.°C.
• Within AC converter cabinets the profibus and motor cables should be as far as possible away.
• In VaTech drive cabinets, the profibus cable must enter and exit from the top for best separation.
• The cable shield must be connected to the ground system (EMI rail) as it enters and exits each cabinet, and commander too! The fastener must be metallic and should completely surround the bare shield of the cable for at least one centimeter. Use EMI clips, metal cable fasteners or metal cable ties. Fastening with plastic cable ties is NOT sufficient.
• Confirm that the cable end coming from the PLC is connected to the IN side of the connector, so that switching on the resistor will keep all intermediate bus stations to the PLC active. At the end of the bus, the OUT connector is not used.

• If two connected profibus devices are not in the same cabinet, a voltage equalization wire (green/yellow 16 mm²) must be pulled parallel to the bus cable and grounded in both cabinets, as shown in the electrical drawings.

• Check the shield connection and retight the cutting terminals.

File:Profibus Connection1.jpg

Siemens Profibus Plug

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Plug Schematic

Data Wire A - Green

Data Wire B - Red

4 Fast Connection

4.1 Sub-D plug-In connector

The PROFIBUS FC Sub-D plug-in connector for field assembly for easy connection of 2-wire FC installation cables (up to 12 Mbps) using a PROFIBUS stripping tool.

File:Fast connection sub-dmit text.PNG

4.2 M12 plug In connector

The PROFIBUS FC M12 plug in connector for field assembly for easy connection of 2 wire FC installation cables (up to 12 Mbps) using a PROFIBUS stripping tool.

File:Fast connection M12.PNG

5 Grounding

File:Profibus Connection2.jpg

Make sure the shield connection is done properly

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M12 plug In connector shield connection

• Grounding has to be done at the plugs and the entries of the cabinets NOT at the shielding plate

File:Profibus Connection6.jpg

This plate has a shielding function between buscables and motorcables

6 Labeling

The cable number must be marked on both ends of each cable, eg. =270G2 –W010

7 Termination

The PROFIBUS is terminated at the beginning and end of the Loop

Active Termination means that there are resistors switched on which Pull up and down to a defined signal level

8 Loop Resistance

Before measure resistance please disconnect master and slave. Maximum resistance for 1,5Mbit is 22Ohm is equivalent to 200Meter (22/110*1000=200meter)

Note: There is no need to disconnect the PROFIBUS subscribers for measuring the loop resistance; as long as the subscribers aren’t energized, the measuring can be performed.