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The I-2532 CAN to Fiber Converter
Quick Start User Guide
1. Introduction
Fiber optic transmission medium is a good material to protect data
transmission from EMI/RFI interference and has been used in harsh
environment extensively. CAN bus is famous in industrial application.
More and more users build CAN networks to communicate their
controllers, sensors and actuators. In order to solve the problem between
different transmission medium, I-2532 is specially designed for converting
the electrical CAN bus signal to fiber optic cables.
The fiber length between two I-2532s can be up to 1.4km (4593ft), it is
mainly decided by the cable attenuation of fiber and the CAN bus baud. I2532 is the economic solution for applications which require protecting the
data transmission from electrical exposure, surges, lightning or chemical
corrosion. Generally, I-2532 can be used in CANopen, DeviceNet and all
the other CAN network which follows the ISO 11898-2 standard.
CAN Device
CAN Device
I-2532
Fiber
Up to 1.4 Km
CAN Device
I-2532
ISO 11898-2ISO 11898-2
CAN Device
62.5/125 µm multimode Fiber
Cable Attenuation of Fiber < 2.8 dB/Km
This quick-start describes how to implement the I-2532 module into
users’ applications in a quick and easy way. Therefore, it only provides the
basic concepts. If users want to know more detail information about the I2532, please refer to the user manual of I-2532 in the product CD or visit
our website as follows:
http://www.icpdas.com/products/Remote_IO/can_bus/i-2532.htm
I-2532 CAN to Fiber Converter Quick Start User Guide (ver. 1.1, 2008/10/03) -----1
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2. Appearance
The following figure is the appearance of the I-2532.
Front View Bottom View
LED Indicators
Fiber Port
Connector Type: ST
Operating Wavelength: 850nm
Fiber Type:
Multi-Mode, 62.5/125µm
CAN Port
ISO 11898-2 standard
Power Port
POWER
TxD
RxD
N/A
CAN_L
CAN_H
CAN_GND
TD
RD
1
2
3
4
5
6
7
8
F.G.
GND
+VS
T.R.
active
T.R.
inactive
+10 ~ +30VDC between
Terminal Resistance Switch
GND and +VS
3. Pin Assignment
Port Name Description
CAN_L CAN_Low, signal line of CAN Port.
CAN
Fiber
Power
CAN_H CAN_High, signal line of CAN Port.
CAN_GND CAN_Ground, ground voltage level of CAN Port.
TXD Transmit data to fiber optic cable.
RXD Receive data from fiber optic cable.
+VS Voltage Source Input. +10VDC ~ +30V
GND Power Ground.
F.G. Frame Ground.
DC.
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4. LED Indicators & Terminal Resistance
The table below shows the meanings of LED indicators on the I-2532.
Transmitting/receiving one message to/from fiber cable will flash the
TD/RD LED once. The TD/RD LED may always be turned on if there are
a lot of messages transmitted on fiber cable.
POWER LED
(Red Light)
on
module
active
off
module
inactive
flashing
TD LED
(Green Light)
messages
transmitting
no message
off
transmitting
RD LED
(Green Light)
messages
flashing
receiving
no message
off
receiving
The switch at bottom of I-2532 is used for adjusting terminal
resistance (120Ω) on CAN Port. The switch functions are shown below.
Active
(Enable)
Inactive
(Disable)
5. Wire Connection
Metallic
Board
Interconnecting
+10VDC ~ +30VDC
Power GND
Earth Ground
CAN_GND
CAN_H
CAN_L
ISO 11898-2 ISO 11898-2
Fiber
Tx Tx
Rx Rx
CAN_GND
CAN_H
CAN_L
+10VDC ~ +30VDC
Power GND
Earth Ground
Roughly speaking, wiring of CAN_GND and FG can improve the
capability of anti-interference of CAN bus system, but this is not necessary.
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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
(L
SEG1
, L
…) and bus length (L
SEG2
) in the same CAN bus system are
BUS
shown in the following figure.
L
L
seg1
= L
BUS
I-2532 I-2532
seg1
+ L
L
seg2
Fiber
seg2
+ L
seg3
ISO 11898-2ISO 11898-2
L
seg3
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 I2532 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 (100025*2=950).
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