Siemens SIMATIC NET PROFIBUS Automatic Transmission Rate Detection, Supported FO Fiber Types

Functional Description

3.3Automatic Transmission Rate Detection

The OBT supports all PROFIBUS transmission rates (12 Mbps , 6 Mbps, 3 Mbps,

1.5Mbps, 500 Kbps and 187.5 Kbps, 93.75 Kbps, 45.45 Kbps, 19.2 Kbps, 9.6 Kbps).

The transmission rate is detected automatically. No settings are necessary.

3.4Supported FO Fiber Types

The OBT supports the fiber types listed in the table below:

Table 3-1 Distance Covered by Fiber-optic Cable between Two Devices on the Optical

PROFIBUS DP

Fiber Type

Plastic FO 980/1000 ∝ m with 2 fibers and max. 200 dB/km cable attenuation

PCF FO 200/230 ∝ m with 2 fibers and max. 10 dB/km cable attenuation

Distance Between Two Devices

0.1m to 50 m

0 m to 300 m

The specified distances between the devices assume that the partner devices use the same optical components as the OBT. This is, for example, the case with the IM 153-2 FO, IM 467 FO and OLM 12M.

The transmission rate is independent of the type of fiber used and the cable length. It can be up to 12 Mbps.

The following accessories are available:

SPlastic FO cable (sold in meters), connectors, polishing set and tools for connectoring plastic FO cables

The plastic fiber-optic cables are supplied with connectors. The plastic simplex connectors can be fitted with the available tools on site.

SPCF FO cable (with connectors)

PCF cables in fixed lengths are available with 4 simplex connectors already fitted.

3.5Displays

The OBT has 4 LEDs for displaying the various states.

3-2	PROFIBUS Optical Bus Terminal (OBT)
	C79000-G8976-C122-02