PROFIBUS Manual

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Navigation: Transmission technology > Synchronous - MBP transmission technology > Network layout

Cable for PROFIBUS PA with MBP

The standard IEC 61158-2 specifies four different types of cable for use in PROFIBUS PA with MBP segments (see table below). MBP type A cable - not the same as RS 485 type A cable – is a two-wire, screened and stranded cable with the best possible performance characteristics regarding signal line loss and cable length.

	Conductor pairs	Shield	Conductor cross-section	Max resistance per unit length	Max total cable length
Type A	A few	Yes (90%)	0.8 mm2	44 Ω/km	1900 m
Type B	Numerous	Over all	0.32 mm2	112 Ω/km	1200 m
Type C	Numerous	None	0.13 mm2	264 Ω/km	400 m
Type D	Numerous	None	1.25 mm2	40 Ω/km	200 m

If type A cables are used, overall cable length, including stub lines, should be maximum 1.9 km. When used in potentially explosive environments and intrinsically safe construction, line lengths are greatly reduced.

It is advisable to use cable type A for new installations. However, it is also practical if other cables can be used, especially when existing systems have to be converted to PROFIBUS PA.