valutazioni - 3, GPA: 3.3
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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. I-2532 CAN Device CAN Device CAN Device Fiber Up to 1.4 Km I-2532 CAN Device ISO 11898-2 ISO 11898-2 62.5/125 .m 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: I-2532 CAN to Fiber Converter Quick Start User Guide (ver. 1.1, 2008/10/03) -----1 2. Appearance The following figure is the appearance of the I-2532. Front View Bottom View LED Indicators Terminal Resistance Switch Fiber Port CAN Port CAN_H CAN_GND CAN_L N/A 1 2 3 4 5 6 7 8 RxD TxD POWER TD RD F.G. GND +VS T.R. active T.R. inactive Power Port ISO 11898-2 standard Connector Type: ST Operating Wavelength: 850nm Fiber Type: Multi-Mode, 62.5/125.m +10 ~ +30VDC between GND and +VS 3. Pin Assignment Port CAN Fiber Power Name CAN_L CAN_H CAN_GND TXD RXD +VS GND F.G. Description CAN_Low, signal line of CAN Port. CAN_High, signal line of CAN Port. CAN_Ground, ground voltage level of CAN Port. Transmit data to fiber optic cable. Receive data from fiber optic cable. Voltage Source Input. +10VDC ~ +30VDC. Power Ground. Frame Ground. I-2532 CAN to Fiber Converter Quick Start User Guide (ver. 1.1, 2008/10/03) -----2 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 TD LED (Green Light) flashing messages transmitting off no message transmitting RD LED (Green Light) flashing messages receiving off no message receiving The switch at bottom of I-2532 is used for adjusting terminal resistance (120) on CAN Port. The switch functions are shown below. Active Inactive (Enable) (Disable) 5. Wire Connection CAN_H CAN_L CAN_GND Earth Ground Power GND +10VDC ~ +30VDC CAN_H CAN_L CAN_GND Earth Ground Power GND +10VDC ~ +30VDC Tx Tx Rx Rx Fiber Metallic Board Interconnecting ISO 11898-2 ISO 11898-2 Roughly speaking, wiring of CAN_GND and FG can improve the capability of anti-interference of CAN bus system, but this is not necessary. I-2532 CAN to Fiber Converter Quick Start User Guide (ver. 1.1, 2008/10/03) -----3 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 (LBUS) 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 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). I-2532 CAN to Fiber Converter Quick Start User Guide (ver. 1.1, 2008/10/03) -----4 ...