Introduction: Communication converter basically applies at supporting the industry of structure of RS485 communication bus line to control automation system. In including meal of entrance guard, carry out, monitoring, Lou Yu to wait for a system to telling parking lot system, check on work attendance among them. Problem one, what is RS485 converter? Communication converter calls 485/232 converter again, abbreviation 485 converter, it is the facility that receives changeover of communication of 485 bus line the computer to string together a mouth to have news report for RS232. Problem 2, what use does RS485 converter have? Converter solved RS232 effectively to string together the following defect that buccal communication exists: 1, RS232 communication distance, theoretic it is many meters 20, actual application suggests not to exceed 13 meters. 2, RS232 communication can undertake be noddinged man-to-manly is opposite ordering news report only, namely one strings together a mouth to be able to receive facility of a RS232 only. Can come true after use RS485 converter: The computer is apart from to theory of last RS485 equipment is 1200 meters (the hand pulls hand couplet to go down) , actual proposal is in 800 meters of less than. An any facility that can attend with 485 bus line through 485 converter have the computer communication, can control in order to have the couplet net of much stage equipment. According to RS485 converter and RS485 equipment (for example: The entrance guard controller that supports RS485 communication) the type selecting of chip and design are different, theoretic a bus line can join 32 64 128 256 485 equipment, suggest 1/3 number that are worth for theory are most stable actually. Communication converter basically applies at supporting the industry of structure of RS485 communication bus line to control automation system. In including meal of entrance guard, carry out, monitoring, Lou Yu to wait for a system to telling parking lot system, check on work attendance among them. Problem 3, how to choose 485 converter? Above all, suggest everybody is chosen the 485 converter of the card, the converter price of card and a less known and inferior brand differs and not quite, have a few money only, the converter of a less known and inferior brand can choose the chip that cheap chip renovates even for managing cost. Next, suggest everybody chooses active converter certainly (the converter that distributed auxiliary power supply namely) the distinction of active converter and passive converter: Active converter distributed igneous cattle power supply, passive converter is done not have, active converter bulk is mixed commonly tobacco case is similar, and passive converter compares lighter commonly slightly big. The defect of passive converter: Stem from the consideration of cost, passive converter can realize the changeover function of RS232 and RS485, but design without interference rejection almost, it is normal that the meeting after using gives the news report when having, sometimes communication is abnormal, in environmental interference bigger circumstance is used very flabby calm. Passive converter did not protect a design almost, more do not talk to go up prevent be struck by lightning, electrostatic to surge lack strong ego to protect ability, still passive converter uses the cheapest chip, make connective equipment was not stabilized more than a few times, transmission distance is very short also. Problem 4, does need choose the 485 converter that photoelectricity keeps apart? Photoelectricity segregation has than common converter in the respect such as interference rejection strengthen, but my individual feels his preventing character of be struck by lightning to seem is self-destruction sex defends principle of be struck by lightning, will protect the important equipment of back end through destroying oneself front, this kind of principle or meeting add those who add an engineer to safeguard workload. So, when the converter that photoelectricity of choose and buy keeps apart, question his ability that prevent thunder carefully. Problem 5, the laden ability of RS485 converter? Laden ability is to point to how to many facility can be taken on a bus line, a farthermost equipment can be received much further. Laden ability is mixed not just ability concerns the design load of converter, and with the design of 485 equipment laden ability is concerned, two want Gao Caihang, among them an index is high, did not use. Have the does not have fine converter manufacturer of some of a less known and inferior brand, meeting empty him elevation laden ability, the professional knowledge of chip of this need understanding and the ability after use test knows, still have nominal value and value of actual stable application are to have bigger difference. CNC Milling
