ICP DAS USA I-2532 quick start Bus Length & Fiber Length, Attenuation dB/km Ideal Fiber Length m

6. Bus Length & Fiber Length

Higher attenuation of fiber will reduce the transmission distance. Users can use following table to know the relationship between those two.

Attenuation [dB/km]	Ideal Fiber Length [m]
2.8	<1400
4	<400

The limitation of baud on a CAN network is restricted by propagation delay. On the other hand, long bus length leads to long propagation delay. The relationship between baud and bus length is displayed below.

Baud [bit/sec]	Ideal Bus Length [m]
500K	< 100
250K	< 250
125K	< 500
50K	< 1000
20K	< 2500
10K	< 5000

The definition of segments the relationship between segment length (LSEG1, LSEG2 …) and bus length (L BUS) in the same CAN bus system are shown in the following figure.

LBUS = LSEG1 + LSEG2 + LSEG3

LSEG1	LSEG2	LSEG3
ISO 11898-2	Fiber	ISO 11898-2
	I-2532	I-2532

When users add one pair of I-2532 into a CAN bus system, the ideal bus length will reduce 50 meters because the propagation delay of one I- 2532 is equal to the propagation delay caused by 25 meters bus length. For example, if users use baud 50Kbps and add two I-2532s into the CAN network, the ideal bus length should less than 950 meters (1000- 25*2=950).

I-2532 CAN to Fiber Converter Quick Start User Guide (ver. 1.1, 2008/10/03) ----- 4