Yaskawa Profibus-DP Option Card CM061 - Manual (Page 60)

Troubleshooting D-8
Wiring And Cabling
Several serial communications troubleshooting issues can be traced to cabling and grounding. The PROFIBUS-DP Option is based on
RS485 differential line technology, and specifies the cable to be used, i.e. cable length requirements, termination requirements, number of
nodes allowed per segment, etc. The following lists and describes the items that should be checked during the network installation to verify
correct cabling and grounding. Failure to follow the following guidelines could result in total or intermittent communications failure.
#
The Network Cable Is The Correct Type.
The cable used by the PROFIBUS-DP network is specified by PROFIBUS European Standard EN50170. It is a shielded, twisted pair cable
with the following specifications. In order for the cable to fit the currently available PROFIBUS-DP standard connectors, the surrounding
diameter must be 8.0mm (+/- 0.5 mm).
Table D.3 – PROFIBUS-DP Cable Specifications
Parameter PROFIBUS-DP Cable Requirements
Impedance 135 to 165 Ohm / 3 to 20Mhz
Capacitance < 30 pF / m
Resistance < 110 Ohm / Km
Wire Gauge > 0.64 mm
Conductor Area > 0.34 mm 2
Shield Density Greater than 80%
#
Cable Is Correctly And Securely Connected
Check for shorts, broken wires, loose connections, and that the signal and shield wires are connected to the correct pin on the option
connector. See Figure C.1 – PROFIBUS-DP Option Connections above for required wiring.
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Cable Lengths Are Within Specified Limits
Both data rate and cable type affect the total allowable length of the network. The total amount of measured linear cable allowed between
any two points on the network segment must be within the following table’s specification. Also, the total amount of network length,
allowed through segment repeaters must be less than the Maximum Network Length in the following table. The minimum distance of cable
that is required between device connections to the PROFIBUS-DP physical media is a distance of one (1) meter.
Table D.4 – PROFIBUS-DP Cable Length Specifications
Baud Rate Maximum Segment Length Maximum Network Length
9.6 Kbps 1,200 Meters 10,000 Meters
187.5 Kbps 1,000 Meters 10,000 Meters
500.0 Kbps 400 Meters 4,000 Meters
1.5 Mbps 200 Meters 2,000 Meters
3.0 Mbps 100 Meters 1,000 Meters
6.0 Mbps 100 Meters 1,000 Meters
12.0 Mbps 100 Meters 1,000 Meters