PROFIBUS is the commonnest spot bus line, have more than 50 million node currently moving. This bus line comes out at was in Germany to develop 1989 at first and be registered to be DIN 19245, international Electrotechnical Committee (IEC) already admitted all sorts of interrelating to PROFIBUS reachs his in IEC 61158 standard format.

 

PROFIBUS comes from bus line of “ process spot (Process Field Bus) the abbreviate of one word of ” , it is to regard a class as serial communication mark at first allow and design. PROFIBUS can coordinate the executive measure of the between each node information exchange in network system. Prime PROFIBUS site runs a system (FMS) be replaced by simpler and agile agreement place, for example PROFIBUS distributed peripheral (DP) , PROFIBUS process automation (PA) and be aimed at ProfiDrive of electric machinery pilot only.

 

PROFIBUS DP is up to now the most popular executive program, and continue maintaining the momentum of driving growth. But, increase what install a measure as new DP network ceaselessly, specific requirement of application also is increasing ceaselessly. Include higher working temperature and segregation voltage among them, and smaller over all dimension. Although a lot of RS-485 are sent and receive implement so-called as compatible as PROFIBUS, but accord with a standard truly have a few only, and what can satisfy system of increasingly severe exacting to ask is fewer.

 

The article will introduce the optimal design of new PROFIBUS DP node, segregation of node of key introduction bus line, accord with PROFIBUS standard and polarity of bus line signal, approve the introduction via PROFIBUS international, segregation technology is based on gigantic magnetism resistor (GMR) new-style segregation is sent and receive implement series, this series includes industry measure the smallest with function the most powerful PROFIBUS is sent and receive implement. The article still will be revealed how to protect node of segregation bus line to avoid the effect that suffers ESD, EFT and instantaneous surge.

 

 

Graph the design of node of traditional segregation bus line of the 1 description in revealing documentation of PROFIBUS DP standard. This circuit uses 3 opto-coupler to send and receive PROFIBUS implement the controller circuit that with its he is ground connection to consult with the earth is apart.

 

 

Graph 1. Traditional PROFIBUS DP node

 

Lucky Sa electron sends and receive GMR isolator and PROFIBUS RS-485 implement compositive, rolled out ISL32740 model to send and receive implement. This parts of an apparatus reduced component amount significantly and reduced power comsumption, rose to be opposite at the same time in all the tolerance of modular voltage and circuit noise. In addition, send and receive implement dependability also rises significantly. Because the mechanism did not wear away in GMR isolator, accordingly this parts of an apparatus need not change in whole lifecycle of application. Graph the 2 typical DP node that revealed use ISL32740 are designed.

 

 

Graph 2. The node of new-style PROFIBUS DP of use ISL32740

 

 

PROFIBUS international level is right send and receive implement voltage of the output that need branch undertook limitative, taboo a lot of at present on the market send and receive implement chip. In carry a condition to fall for nothing, limitation of voltage of the biggest bus line that need branch is in 7VPP. And to the biggest load, limitation of the least value is 4VPP.

 

A lot of RS-485 that have high output drive are sent and receive implement the least value that can satisfy 4VPP, but it is easy to because produce the voltage that need branch to be as high as the driver of 8.5V,be compared, often can exceed the maximum of 7VPP. But here, not be voltage had jumped over higher.

 

Because this needs to notice, if did not use those who accord with 4VPP to be restricted to 7VPP,send and receive implement, the product that will bring about any application PROFIBUS attestation cannot pass attestation. The problem that another application can encounter is to send and receive implement the voltage that need branch asks to be in the biggest appoint power source voltage next measurement, send and receive to 5V implement for, it is 5.5V normally. PROFIBUS test lab is adding up to the meeting in compasses sex test to use condition of this one worst.

 

 

RS-485 standard will be sent and receive explicitly implement terminal A and B define bus line to turn over photograph terminal to turn over photograph and blame respectively. However, all sending and receive implement manufacturer uses contrary regulation, dispute of its terminal A is turned over, terminal B is to turn over photograph terminal.

 

This phenomenon continues all the time up to now. PROFIBUS is met according to EIA-485 standard, will be not turn over photograph terminal to distribute B line, will turn over photograph terminal to distribute A line. But, of the whole world send and receive implement manufacturer still is using contrary signal terminal definition.

 

The signal regulation that appoint and uses actually does not match to perplexing personnel of network research and development all the time. The solution of this problem actually very simple, of the node of 50 million PROFIBUS that installs up to now send and receive implement A is turned over to be not, b is carried to turn over, abide by regulation of this one signal to be able to ensure the design of personnel of research and development and 50 million node that will not will be installed are compatible.

 

 

In roll out PROFIBUS of model of ISL3159 of blame segregation type to send and receive implement hind, lucky Sa electron this parts of an apparatus and digital isolator (be based on GMR technology) compositive to individual in enclosing, roll out ISL3274x series to keep apart type then PROFIBUS is sent and receive implement. Original ISL32740EIBZ design climbs electric distance and limits of standard industry temperature in the light of strict requirement 8mm – the 40°C application to 85°C.

 

To the concentrated design that need small size encloses, in can applying same solution the smaller 16 QSOP that cite a base to enclose, realize miniaturization to the greastest extent thereby, still can maintain at the same time – 40°C comes the working temperature limits of 85°C. According to the demand of PROFIBUS user, need to reach the taller environment temperature of 115°C and 125°C in the following design certainly. Use the 8mm, 16 wide body SOIC that cite a base to although can be offerred,be enclosed right now enough low thermal resistance can continue to work below 125°C, but fine rate can be reduced. This is the reason that lucky Sa electron rolls out ISL32740EFBZ of isolator of high temperature PROFIBUS.

 

However, real design challenge comes from the user at medical treatment and robot application domain, they have higher temperature demand not only, still need VDE to enhance segregation. For this, the ISL32741EIBZ that lucky Sa electron rolls out and ISL32741EFBZ design use 6kV isolator, part corresponding industry and limits of patulous industry temperature. Although these application use RS-485 normally, is not PROFIBUS DP, the PROFIBUS of Dan Ruisa electron is sent and receive implement accord with these two standards at the same time. Watch 1 listed all sorts of PROFIBUS are sent and receive implement have character only. Need to notice, all sending and receive implement come in 3.0V of 5.5V advocate when power source and 4.5V leave the job to the auxiliary power source of 5.5V, rate of the biggest data is 40Mbps.

 

 

 

Express 1. PROFIBUS sends and receive segregation type implement

 

 

The application for ISL32740E can carry the twinkling that exceeds compression of parts of an apparatus to change, need increases voltage of an exterior transient state to restrain implement (TVS) . For this, lucky Sa electron chose Semtech RClamp0512TQ, because it has capacitance of level of protection of tall transient state, small knot and small over all dimension.

 

 

Express 2. RCLAMP0512 TVS character

 

TVS is mixed in bus line segregation ground connection (GNDISO) between carry out, if pursue,3 are shown. The transient state voltage that goes up as a result of bus line in order to receive ground potential (also call protective ground contact, PE) for reference, insert high-pressured capacitance between GNDISO and PE accordingly (CHV) , change for high frequency twinkling provide low impedance return. Those who require an attention is, the metallic box that often carries equipment with the join of PE or very short low inductance line come true.

 

Add resistance of a high pressure (RHV) as shunt-wound as CHV, can prevent float ground (GNDISO) with cable screen (use at PROFIBUS normally) in electrostatic accumulation. Express the 3 material detailed list that listed this circuit place needs.

 

Graph 3. Have the node of segregation type PROFIBUS DP that transient state protects

 

 

Express 3. Material detailed list

 

 

A lot of equipment can move in PROFIBUS DP node. But among them only little part accords with 7VPP DP standard of the biggest voltage that need branch. ISL3274xE segregation type is sent and receive implement accord with PROFIBUS standard, approbate via PROFIBUS international, can use at DP node. They use GMR isolator technology to come true to be kept apart basically with aggrandizement, eliminated design risk and quicken a product to appear on the market time.