linear axis positioning with industrial servo motor
Contents
1. synchronous the nominal current of the motor is 4 A and the nominal voltage is 230V AC S50 60 Hz The maximal current is 10 A and the signal speed through the RS232 port is 9600 115000 bits s In Table I the data of the motor controller can be seen TABLE II GENERAL TECHNICAL DATA OF THE MOTOR CONTROLLER Nominal output current 4A Peak current 10 A Max intermediate circuit voltage 380 V DC Mains frequency 50 60 Hz Max nominal input current 5A In Fig 4 the driver configuration can be seen in the FCT program Every part of a system should be set with all parameters by this program and after it can calculate the details for example the maximum speed which is stored in its memory and it can be found in the user manual of the devices 140 Drive Configuration Controller Controller Type CMMS AS C4 3A G2 Option Slot Empty Motor Motor Type EMMS AS 55 S TM Gear None Brake No Axis Axis Type EGC 50 600 TB KF GK Gearbox None Parallel Mount No Fig 4 Driver configuration For the accuracy of the positioning we use the encoder which is mounted on the motor shaft and the limit switch of the linear axis We set the home position with using this Reed sensor The slider goes to the limit switch the side depends on the settings and after reaching it it goes immediately into the opposite direction The slider stops when the signal is changing this position is taken as the homing point ST Swi2. 0 04 MODE SELECT THEN RESET 02 6 MODE DIN12 RESET 02 7 MODE DIN9 SET P2 POSITION RESET P3 JOG JHP TO MODE SEL IF F0 64 MODE SELECT THEN RESET 02 2 START TEACH RESET 02 7 MODE _DIN9 SET 02 6 MODE DIN12 SET P3 JOG RESET P2 POSITION JMP TO MODE_SEL Fig 9 Part of the main program of the PLC In Fig 9 can be seen a part of the main program when it is deciding about the mode in step Mode_sel the states is checking all the time With the first if it is looking for whether the Home button has been pushed or not With the second if it does the same with the reset button If these variables are true the program jumps into another steps We are also pay attention of the Mode select bits statements and base on them it activates or deactivates programs If there is not homing the main program is continually be in this step ANNALS OF THE ORADEA UNIVERSITY Fascicle of Management and Technological Engineering ISSUE 1 MAY 2014 http www imtuoradea ro auo fmte SELECT PLACE OF TEACHED POSITION 2 20 S80 may NO VELOCITY IS FIXED 200 mm s CONTROLLER READY i j MOTION CUMPLETE HANUAL NOVIE TEACH POSITION move no HOUE MOUE SELECT PLACE TO SAVE ACTUAL POSITION Bb eS L SCREEN SELECT VELOCITY mm 5 190 SELECT POSITION mm MOTION COMPLETE ERROR i HOME Fig 10 The menu structure 6 VI INTRODUCTIO
3. ANNALS OF THE ORADEA UNIVERSITY Fascicle of Management and Technological Engineering ISSUE 1 MAY 2014 http www imtuoradea ro auo fmte LINEAR AXIS POSITIONING WITH INDUSTRIAL SERVO MOTOR X nia Erzs bet TOTH Janos T TH PhD email tothxeniaerzs gmail com tothjanos eng unideb hu University of Debrecen Faculty of Engineering Abstract Processions controller devices and positioning tasks with different conditions are quite important in industrial automated systems The aim of this paper was to materialize a system which is an industrial application with using industrial devices The main part of his teachable system is a PLC controlled servo motor With it the user can set different positions on the linear axis with different velocities moreover it gives the possibility to define new places and to make a program to control a whole sequential process The user can control this system with an industrial display HMI Its interface is user friendly with easy manageability therefore it can be used without programming knowledge Keywords servo motor positioning PLC HMI programming I INTRODUCTION HE practical applications of the servo motors is very important in the industry In this paper we use it with a tooth belt linear axis for positioning It can be made in different ways such as controlling with a PLC own table which is good for repeatedly running using a software on the computer
4. Enable Control DINO6 Limit Switch 0 DINO7 Limit Switch 1 DIN12 Mode Select Bit 0 DIN13 Stop Offline View of the mode dependent I O Configuration Single position set Offline Mode Fig 6 Digital I O of the motor controller The controller also has digital outputs with them we can make sure for example about the errors the end of the positioning or the controller is ready for the operation In this case we can send the next instruction to it With the Mode Select Bits we can choose between two modes 00 is simple positioning and 10 means teaching new positions or crawling on the axis In Single Position Set Mode we use the selection bits to define positions We can see the used positions and profiles in the Fig 7 Position List Position Profiles A 20 00 0 END A 100 00 1 END A 180 00 2 END A 260 00 3 END A 340 00 4 END A 420 00 5 END A 500 00 6 END A 580 00 7 END oo o oo 090 2 ojo o ioio ioico Sc Fig 7 Used positions velocities in the FCT In Jogging Teaching Mode with DIN10 and DIN11 inputs we can change the direction and rotate the motor slowly with 50 mm s and after 1s the speed changes to 200 mm s Fig 8 With this function we can find new positions and with sending an impulse to DIN8 we can store them to the DIN1 DIN4 defined place Crawling Crawling Velocity 50 00 mm s vit Slow Moving Time 1000 ms vma Jog Para
5. N OF THE USER INTERFACE For the easier operating we created a menu structure which can be seen in Fig 10 With pushing the buttons on the main screen in the middle we can select the other screens Before starting the program it goes automatically to its home position but with the home button the user can do it manually whenever it is necessary The program can be restarted with the reset button In the Positioning screen right on the top we can select between 8 fixed positions which can be seen in the Fig 7 The long green line under this function symbolizes the linear axis and the target position on it We can choose fixed velocities Fig 7 to every position and the indicator lights on the right side show information about the state of the controller In Manual move amp Teach position screen left below we can move the dray with pushing move or move buttons If it stops we can select a place 1 7 in the controller for the new position and save it with the Teach button If we have manually taught positions we can load them with the screen on the left top We can choose the number of the position and push the move button It will go to the defined place with a fixed velocity 200 mm s With the last screen on the right below called Position set table we can set a whole sequential program We can describe the positions choose a velocity and set a delay time which means the time for waiting before starting the movem
6. On the other hand these options can be connected with an industrial display too II GENERAL INFORMATION ABOUT THE SERVO MOTOR Positioning means moving a mass from a point to another For this we use a FESTO EMMS AS 55 S TM servo motor The brushless servo motor contains a three phase stator and a permanent magnet rotor The rotational speed of the rotor depends on the frequency of the rotational magnetic field through the stator windings The rotor moves synchronic with the magnetic field of the stator and follows it with the same revolutions Fig 1 P With this formula we can see that the speed of the motor n is proportional with the stator frequency and in inverse ration to the number of the poles p The name of the used motor means that this three phased brushless servo motor with the flange size 55 mm is equipped with an inductive multi turn encoder mounted on the motor shaft This feeds information goes back from the motor to the controller It means that we use a closed loop system Fig 2 rotating magnetical field D rotor with j permanent magnets Fig 1 Structure of a servo motor 3 The user gives the instructions with the HMI and it sends them to the PLC After processing this information the PLC sends them to the motor controller which consists of a programmable controller and an amplifier The commands about the direction the distance the speed and the acceleration forward to th
7. e actuator motor The sensor measures the real values and sends back the actual information to the controller Based on this feedback the controller after the comparing decides how much correction is necessary It continues repeatedly until the instruction is completed to maintain the motor at the specified position and state The data of the completed motion goes back to the PLC and base on this information it gives the next instruction The more important information for the user can be seen on the display Feedback signal Fig 2 The used closed loop system ANNALS OF THE ORADEA UNIVERSITY Fascicle of Management and Technological Engineering ISSUE 1 MAY 2014 http www imtuoradea ro auo fmte Motor controller Fig 3 The used system IHI USED MOTOR AND ITS CONTROLLER We use a FESTO EGC 50 600 TB KF GK_ tooth belt linear axis with 50 mm axis size and 600 mm working stroke Without it the data of the motor are the following TABLEI GENERAL TECHNICAL DATA OF THE SERVO MOTOR Nominal torque 0 68 Nm Nominal speed 6600 rpm Nominal voltage 360 V Nominal current 1 2 A Torque at standstill 0 98 Nm Maximum speed 7330 rpm Peak torque 2 7 Nm Maximum current 5A With using the linear tooth belt axis it limits the range In this case the maximum speed of the motor is 3000 mm s and the maximum acceleration can be 50 mm s The used motor controller is a FESTO CMMS AS C4 3A G2 which means the motor technology is AC
8. ent After giving the details every used line should be fixed otherwise the program skips them If a position is reached the indicator light of the row shows it The process starts repeatedly from the beginning if the repeat button is pushed 142 VII CONCLUSION AND RECOMMENDATIONS This process and these settings can be quite difficult and needs the good knowledge of the devices Our aim was to create an interface to this system with a simple structure for a common user It means that it can be used easily without the deep knowledge of programming or of using softwares VII REFERENCES 1 Mohamed A El Sharkawi Fundamentals of electric drives Cengage Learning 2000 Janos Toth Electrical Actuators University of Debrecen Faculty of Engineering 2012 David Hoey Dan Sandoval Edward Gasper TP 800 e drives Reference notes Festo Didactic GmbH amp Co D 73770 Denkendorf 2002 http www festo com net SupportPortal Files 102 73 EMMS AS_ENUS pdf download 20 04 2014 5 http www festo com net SupportPortal Files 102 72 CMMS AS_ENUS pdf download 20 04 2014 6 http www youtube com watch v c2RhX UsSxtE 2 3 4
9. meters Max Velocity 200 00 mm s y Acceleration 1 000 ms ol Deceleration 1 000 mis ter Smoothing 100 Fig 8 Jog parameters 141 V THE CONNECTION BETWEEN PLC AND HMI The center part of the controlling is a FESTO CPX Programmable Logic Controller which has a modular structure and its programming interface is the Festo Software Tools software We used an STL programming language which describes sequentially processes A Festo FED 500 type HMI Human Machine Interface provides the necessary information about the system s functioning for the user and makes the connection between the system and the user It has a pressure sensitive resistive touch screen and it communicates with the PC and the PLC via serial port The signals of the limit switch and the digital outputs of the controller go into the two digital inputs module of the PLC From the two digital outputs module of the PLC goes the necessary enable and input information towards the motor controller through a parallel cable which has 25 pins The variables that were used during the HMI programming are defined as flags inside the PLC program The structure of the program consists of two parts the main program that operates the other low class programs it makes them active or inactive depends on the criterions STEP MODE_SEL IF F0 66 HOME THEN JHP TO HOHE IF FG 67 RESTART THEN RESET FG 67 RESTART JHP TO INIT2 IF N F
10. tch Fig 5 Homing of the linear axis 4 IV INTRODUCTION OF THE SYSTEM The configuration of the motor controller can be done with the FESTO Configuration Tool program In one motor controller with using digital I O mode we can store 63 different positions and 8 profiles velocity acceleration and deceleration To control the system with the PLC we have to know the pin assignment of the motor controller in order to be able to give the right commands to the enable inputs During the process we define the number of the needed positions with the binary code of the six Record select bits Fig 6 The first one 000000 means the home position and after we can choose from 63 positions We can define also 8 profiles in the motor controller and with using these combinations we can make the PLC program which chooses between them depending on the user needs ANNALS OF THE ORADEA UNIVERSITY Fascicle of Management and Technological Engineering ISSUE 1 MAY 2014 http www imtuoradea ro auo fmte m Mode Selection over DINOS and DIN12 IV active Active Mode PO m Digital Inputs Digital Outputs DINOO Record Select 0 DINOS Start Positioning DOUTOO Controller ready for operat DINO1 Record Select 1 DINO9 Mode Select Bit 1 DOUTO1 Motion Complete DINO2 Record Select 2 DIN10 Record Select 4 DOUTO2 Acknowledge Stat DINO3 Record Select 3 DIN11 Record Select 5 DOUTO3 Errn sti DINO4 Enable Power DINO5
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