Graviman Manual
Contents
1. 1 Check loader and pipes Is the loader switched on Is there a blockage or a leak 2 Check vacuum motor Isolating switch off Tripped overload 3 Check source silo for lack of material or blockage Is the material moist 4 Check compressed air pressure should be 6 8bars 5 Check and tune the tank sensor 21 7 1 3 EX_1_Screw_Capacity_1_too_high Meaning Channel 1 Screw feeder output is too high Possible causes 1 Weight per volume of a new material is high compared to the previous material 2 Screw feeder is the wrong size 3 Malfunction in the screw feeder speed controller Action 1 Tune the modeling control 2 Replace the screw Retune the modeling control 3 Call a qualified technician 7 1 4 EX_1_Screw_Capacity_1_too_low Meaning Channel 1 Screw feeder output is too low Possible causes 1 Weight per volume of a new material is low compared to the previous material 2 Screw feeder is the wrong size 3 Malfunction in the screw feeder speed controller 4 Dirty or worn components in the motor screw or shaft Action 1 Tune the modeling control 2 Replace the screw Retune the modeling control 3 Call a qualified technician 4 Check the overload lamp on the speed controller Reset by disconnecting the power for 5 seconds 5 Clean the screw and screw motor Check the bearings and other parts for excessive wear 7 1 5 EX_1_grav_1_2. OPERATOR BANELEGRAVIMAN Li cea 10 4 GRAVIMAN STRUCTURE AND OPERATION ssssssssssssccsscescsescsecescessessssseseseseseees 11 4 1 CONTINUOUS GRAVIMAN WEIGH UNIT ccsssscecceeesesssseeecesesenseaeeesceesesseeeeesccssauaeeseeeesenseaeeesesses 11 4 1 1 Structure of the Continuous Wei gh Unit ccccccccssccsceesecesecsecessceseeseceeceseeseceaeeeeeeeeeeseeeeeeneeeaeens 11 4 1 2 Principals Of operation mra oiera nono E ea aE a narran rr carr naar naar nano 11 4 2 CREATING A CONTINUOUS DOSING SYSTEM ccscsesesssseeecesesesseceeesccesesseeeeesccessuaeececeesensuaeeeeeees 11 4 2 1 Dosing system Operation ccccsecccssceesseessceesceeescecseceesceceacessaeeeaceseacessaeeeeaeseaeeseaeeesateeseereaeees 11 4 3 THE GRAVIMAN AS A CONTROLLER c cccssscsesssseeceeeeseseaeeecesesenseaeeesceceesesseeceesesesaaaeeeseeesauaeeeseeens 12 4 4 LINE OPERATION USING MAIN PLC AND GRAVIMANSS cccsesesseceeescsesesseeceesecessuaeececessessuaeeesesans 12 4 4 1 Manual mode Operation o cccccccccccescceseesseesecssetsceesecsceesecesecseceseceseseeeeseseeeeeeeaeseseeeeeseeeeeeaeeeaeens 13 4 4 2 Auto MOE OPerati0M a a a E a a a E e E RES EEES 13 5 UNLOADING AND CLEANING THE SYSTEM eeeseesesssesessescosessecosoeccoeseesessesoesoseoscssosesse 14 5 1 CLEANING THE MAIN CHANNEL erosio stitsen serres ESE EERE EEEE EEEE ECESE Esak 14 5 2 CLEANING THE ADDITIVE CHANNEL sssessseccesceeseuceeceeeeseseeceeesesesesseeesesceesesaeeeeesceesauaesees
3. Holding tank level sensor Pneumatic shutter Load Cell Weighing bucket Additive weighing unit Additive holding tank level sensor Additive Load Cell E E 8 Additive Pneumatic shutter 10 Additive Weighing bucket 11 Screw feeder 12 Center pipe Figure rl 1 General Component Layout 4 1 3 Safety Precautions e CHECKING AND REPLACEMENT OF ELECTRICAL PARTS MUST BE PERFORMED BY QUALIFIED PERSONNEL ONLY e DISCONNECT THE ELECTRICAL POWER SUPPLY BEFORE SERVICING e DISCONNECT THE AIR SUPPLY BEFORE SERVICING PNEUMATICS ATTENTION The pneumatic shutters operate automatically and may change position without warning e The electrical cabinet contains an electrical potential of 220VAC The key to these doors should be in the possession of service personnel only 1 4 Power and Air Supplies 1 4 1 Power Supply Single phase 220V AC 50 60Hz 1Amp electrical power supply 1 4 2 Compressed Air Supply Dry non lubricated compressed air at 6 bars of pressure 2 Installation 2 1 Overview The following is an overview of the steps required to install the Graviman unit and check that 1t is working properly The description assumes some prior technical knowledge For more information contact Sysmetric Ltd When installing this system a few basic rules must be observed Leave all service hatches clear of obstruction The unit has to be positioned firmly on the feed throat of the production machine Th
4. and then return 2 grams A failure in the hysterasis test means the weighing bucket is being obstructed in some way Find and fix the problem Wait 10 seconds for the bucket to stabilize Perform action tare to zero the mass reading Calibration test Open the service door and place a reference mass on the bucket tray It is good to use reference mass of at least 1500gr The Act value should show the correct value allow a tolerance of 2 grams If the weight reported doesn t match recalibration is needed Perform action calibration Note After first calibration the process should always show that the system is ok If error is detected it is best to find the reason for it usually mechanical and not to just to recalibrate 9 Linearity test Place a different weight on the tray and make sure that the Act value matches that of the new weight This can be repeated with additional reference weights to verify the whole range If the range is not linear the weigh unit bucket load cell or amplifier must be checked and fixed Calibration should be performed only with the biggest reference mass Remove the calibration weight and close the service door Turn the selector switch back to lt AUTO gt position 17 6 4 Amplifier card Tuning Each weigh unit has its own amplifier card Amplifier cards can be found in the junction boxes adjacent to the weigh units Tuning should be attempted only after the repla
5. ee T Terminating resistance switch Refer to p 64 ple y E A slide switch Use this switch to set the terminating resistance to ON for ho a pr the nodes at both ends of the Controller Link Network a o lo A ies sl 5 Ex_A Ex_1 11 1 suo lo See de Coico Lk Newsies ciate cable twisted pair cable Ex_B Ex_2 12 2 38 Ex_C Ex_3 13 3 Terminating Tenmnellng Ex_D Ex_4 14 4 re de resistance i L 2 Ex_E Ex_5 15 5 Terminating ym GD Ex_F Ex_6 16 6 TR fens Ground Ex_G Ex_7 17 7 Vacuum Ple 20 Not used For full detail see CLK manual PDF CLK CONFIGURATION dm6000 is an index number for the plc program in order to transfer the graviman registers to the data link area J Datalink Component alex File View Table Online Options Help m m E El 4 1 s E EJ PLC Fal Show Hide Gffset Ready Controller Link No Device No Mode Offline Bs SGOHBOGAI2e20aRa Mo Ya 4 0 4207 7090 84 om 3 Console and Switches 3 1 Operator Panel graviman 1 OPEN CLOSE AUTO GRAVIMAN Graviman 1 The Operator Panel contains the following components 1 Graviman 1 switch lt open gt lt close gt lt auto gt e lt open gt the valve is always open for system drainage e lt close gt the valve is always close also for calibration mode e lt Auto gt auto mode normal operation 2 Graviman 2 switch lt open
6. 3 P3 Air Cylinder 16x50 ISO Filing Valve 4a ElO10x15 Load Cell 15kg Tedea 1010 old high profile 62mm 4b El040x15 Load Cell 15kg Tedea 1042 new low profile 40mm P101 Solenoid Valve 24V DC 5x2 1 8 E CQM51CPU NL CPU for CQM PLC CQM1 ID212 Input CQM card CQM OD212 Output CQM card E NT11S SF12 Omron NT11 screen P200 Air regulator with filter 24
7. gt lt close gt lt auto gt same as graviman 1 3 lt Teach gt push bottom fast parameter teaching of new material Graviman 2 panel 10 4 Graviman Structure and Operation The Graviman is flexible device suitable for several uses A continuous weighing system dosing system weight control system or as a combination of any of these 4 1 Continuous Graviman weigh unit The Graviman weigh unit can be operated in one of two ways 1 Asa single unit fixed straight on the feed throat of the production machine working as a continuous weight controller with one type of raw material 2 Asacombined dosing and weigh controlling unit with a number of Graviman weigh modules A central unit doses straight into the main outlet pipe while secondary additive units use screw feeders to dose to the outlet pipe The central unit calculates the desired throughput while the secondary units adjust their screw feeder outputs accordingly 4 1 1 Structure of the Continuous weighing unit The Graviman Continuous weigh unit constitutes the heart of the system It provides precise loss in weight information from the weighing bucket to the PLC controller The unit has been designed to protect the bucket from all kinds of disturbances The weigh unit is made up of three main components 1 Outer housing 2 Pneumatic shutter 3 Weighing bucket with Load Cell e The housing protects the weighing process from being disturbed in any way Two serv
8. in performing a test if the unit failed a previous test For example if the unit fails the hysterasis test then there s no point in performing the calibration test because there s some friction mechanical or otherwise that is preventing the load cell from working properly gt 16 6 3 1 Calibration procedure l 2 3 Move selector to lt CLOSE gt mode Empty material from bucket as explauined above Read EX_1_GRAV_1_Hopper_voltage Amplifier voltage EX_1_GRAV_1_Hopper_weight Mass and enter EX_1_GRAV_1_Ref Mass calibration reference mass value see example screen below posssssccssococsossossosooosso EX_1_GRAV_1_Hopper_voltage INT D4712 EX_1_GRAV_1_Hopper_weight INT D4711 EX_1_GRAV_1_Calibration BOOL2000 05 1 23 Ag EX_1_GRAV_1_Tare BOOL 2000 0 e To perform TARE turn on EX_1_GRAV_1_Tare e To perform CALIBRATION turn on EX_1_GRAV_1_Calibration When there s no load on the bucket the voltage displayed should be 0 0 0 2V If the display exceeds this tolerance make sure the weighing bucket is empty and has no forces exerted on it When the bucket is free and empty perform the calibration procedure Hysterasis test Gently press the weighing bucket and release it The value in Act should increase and then drop back to its original value Allow a tolerance of 2 grams Gently pull the bucket up and let go of it the value should drop momentarily below its original value
9. AP EX_1_GRAV_1_MIN_SCREW_CAP This check allows disqualification of samples that occurred during disturbances If the deviation continues for 3 consecutive samplings a warning is issued Low High throughput 3 Normal control output signal EX_1_GRAV_1_Control_dev calculation Good samples are analyzed statistically EX_1_GRAV_1_Average_Screw_Capacity Average and standard deviation s d EX_1_GRAV_1_S_D_Screw_Capacity results are used in further analysis The results are passed through a high order digital filter and allows the system to adjust itself to rapidly fluctuating material flow conditions The digital filter is the final stage EX_1_GRAV_1_Control_Screw_Capacity The difference between filter output and the average of the last 10 results is the control output signal known as the control error c e EX_1_GRAV_1_Control_dev 19 EX_1_GRAV_1_Last_Screw_Capacity Last result screw throughput in Grams per percentage of full scale screw speed EX_1_GRAV_1_Average_Screw_Capacity Average screw throughput of the last ten legitimate results in Grams per percentage of full scale screw speed EX_1_GRAV_1_S_D_Screw_Capacity Standard deviation of the last ten legitimate results EX_1_GRAV_1_Control_dev Control signal should not exceed one standard deviation Should the system digress occasionally please consult Sysmetric EX_1_GRAV_1_MAX_SCREW_CAP Typical maximum
10. CREW 2 Over A naive eee ces dasseeve cee 23 74 7 EX 1 OW PLC Bauety iii tdi 23 7 AO EX 1 on GRAV Ll O aiii daa irte 23 1 Introduction The Graviman Continuous Dosing Unit is used to keep track of raw material flow using a loss in weight method With this method the rate of weight reduction in the weighing bucket is consistently monitored It is possible to integrate a number of weigh modules with an Additive feeder gravimetric control in order to realize a mixing blending facility The weighing bucket is filled automatically System Control is based on an OMRON CQM1H CPUS 1 industrial programmable logic controller An advanced method of controlling named Control Modeling Method as opposed to regular methods such as PID etc is employed by the Graviman in order to control the speed of each screw feeder in the system The Control Modeling Method boasts many advantages high accuracy immunity to many kinds of disturbance non linear control and very good stability 1 1 Features e Semi automatic calibration e A combination of hardware and software signal conditioning and filtering ensures shock and vibration resistant operation e No need for tuning or setup when replacing raw materials e One year warranty on parts Sysmetric conditions 1 2 Components Description of two combined Graviman units with a connective screw feeder Used when blending of materials is required 1 Main weighing unit 2
11. Cleaning must be accomplished before switching between materials It is advisable to clean the system before a long break in operation depending on the material s sensitivity to moisture absorption Before emptying the Graviman all external feeders and loaders should be stopped The lt graviman gt switch should be on lt AUTO gt or lt OPEN gt mode Additive channel Main channel 2 Figure r5 1 Two channel system layout 5 1 Cleaning the main channel Stop material feed to the main channel 2 Open material drain valve not part of the system When bucket level will drop the material valve will open and the main channel hoper will empty as well 3 Once material flow stops open service door and use compressed air to clean the valve and bucket apparatus 5 2 Cleaning the additive channel Stop material feed to the additive channel 2 Mount a proper bucket below the additive drain flap and motor 3 Open one gear motor pivot screw flip motor sideways open material drain flap Material will now flow into the drain bucket When weighing bucket level will drop the material valve will open and the additive channel hoper will empty as well 4 Once material flow stops open service door and use compressed air to clean the valve and bucket apparatus NOTE Don t exert any pressure on the weighing buckets Pressure above 15Kg 10lbs will cause damage to the load cells 14 6 Maintenance and Servicing Each ma
12. GRAVIMAN Continuous Loss in Weight Dosing amp Control System USER S MANUAL EDITION 3 1 July 2004 Sysmetric Ltd claims proprietary rights to the material contained herein It shall not be reproduced disclosed or used for manufacturing purposes without the express written permission of Sysmetric Ltd Copyright 2002 2004 Sysmetric P O B 1122 Afula 18550 Israel Tel 972 4 6405858 Fax 972 4 6405855 Email info sysmetric ltd com Contents LS INTRODUCTION aar eras easet aoao esee oa enbessdeaiacesapvecsesbeseadecabaseensespasaadbcosepechedeoateasgassag 4 le FEATURES 000 tilda e rd darte ea 4 TD COMPONENTS AEE ET E E A betas E CAs E 4 RERIN ARA ANOA N ON E E E E eevee ees 5 1 4 POWER AND AIR SUPPLIES ee poora a a aea a E rata S aldea dee side Weer NENS 5 LALPO WEE Supply eee e E E E T E AE Aa a Od naka a e EET 5 1 42 Compressed Ate sSUPDUY serii e eiii Acad dasa y iia 530 5 ZeINS TAELA TION sicsisssscssscsseceadesccswanse dees cncesedensnsaseene dose cadsntansases susedsoisencensdonssedesoassaseseceasesadsus euse 6 DV OVER VIB iii 6 2 1 1 Top Flange holding tank flange c cccccccescssccescesceesseseeseceeeneeeeensecsceeseceaeeeeceseceeseeeeseceeceneeeeees 6 Del 2D BOOM ias a 7 2 2 INSTALLATION AND CHECKING PROCEDURE csssssssscececsesesseceeeceseseseeceeescessaeaeeeeecesecseneeesceseaaeaes 7 3 CONSOLE AND SWITCHES csscccsscssscsssssessssesccccsscssscesssessesscseccseessesescesssesesesessoesensees 10 3 1
13. WEIGHINGerror Meaning Channel 1 reporting excessive weight in the weighing bucket Possible causes 1 Material overflow in the weighing bucket 2 Load cell dirty or out of calibration Action 1 Check compressed air pressure should be 6 8bars 2 Clean the load cell as needed 3 Calibrate the load cell 22 7 1 6 EX_1_screw_2_over_current Meaning Channel 2 reporting screw feeder speed controller malfunction Possible causes 1 Material overflow in the holding tank Make sure the system is not flooding the tank with material Action 1 Check and tune the tank sensor see section 6 1 2 Call a qualified technician 7 1 7 EX_1_LOW_PLC_ battery Meaning PLC memory backup battery is low on charge If it is not replaced in time the PLC could lose its program and memory contents Action 1 Replace the PLC memory backup battery 7 1 8 EX_1_on_GRAV_1_off Meaning The extruder is working and the gravimen selector switch lt close gt Possible causes 1 graviman selector switch is lt close gt 2 the extruder is off but EX_1_ON bit is on Action 1 turn the graviman switch to lt auto gt 23 8 Spare Part List When ordering spare parts specify the Item number Catalog number and description Consult Sysmetric regarding spare parts not shown here Item Catalog Number Description 2 El 30mm Capacity switch 24V DC sometimes located higher then shown
14. cement of the load cell or the amplifier card itself The cause of any other weight digression should be found and dealt with Voltage irregularities are usually caused by a loose or dirty component in the load cell 6 4 1 Tuning procedure 1 Connect a Digital Volt Meter DVM to the output terminals of the amplifier card red amp black wires 2 Select the Vdc range 3 An empty weighing bucket should read OVdc 100mV If not adjust by turning the ZERO trim pot 4 Open the service hatch and place a reference weight on the special tray The output should read 1Vdc for every 0 5Kg of weight Adjust using the CAL trim pot 6 5 Graviman Modeling method of control An advanced method of controlling named Control Modeling Method as opposed to regular methods such as PID etc is employed by the Graviman in order to control the speed of each screw feeder in the system The Control Modeling Method boasts many advantages high accuracy immunity to many kinds of disturbance non linear control and very good stability During normal operation the Graviman samples and learns the angular throughput throughput per rotation for each screw feeder in the system It uses this information to calculate the screw speeds needed to yield appropriate proportional throughputs The learning process is gradual Relevant data is processed and selected using statistical algorithms Dedicated paramet
15. ct the timing of throughput calculation A fast rate of calculation will result in rapid assessments but the outcome will be erratic owing to the nature of the process A slow rate of calculation will result in good average accuracy but will fall short on the learning rate of the system Correct tuning of the parameters will result in a calculation being performed every 3 to 10 seconds with a standard deviation of about 2 Standard deviation results are displayed Setting EX_1_GRAV_1_SetdM Set partial derivative of Mass loss in weight Minimum mass factor for calculations Recommended value 0 050Kg EX_1_GRAV_1_SetdR Set partial derivative of Revolutions a constant times screw revolutions Sets minimum screw revolutions threshold for calculation Recommended value 10 units EX_1_GRAV_1_Last_dR EX_1_GRAV_1_Last_dM Actual derivative values calculated by the system The correct ratio of the two parameters SdM SdR should result in actual values last_dM last_dR just above the derived calculation threshold Adjust accordingly 6 5 3 Control Modeling results 1 General Each calculation produces a result of dosing screw throughput grams per revolution The result is converted to a normalized percentage scale EX_1_GRAV_1_Last_Screw_Capacity based on full scale screw ratings 2 Erroneous result Result EX_1_GRAV_1_Last_Screw_Capacity is compared to minimum maximum values EX_1_GRAV_1_MAX_SCREW_C
16. e unit has to be guarded against sources of mechanical damage forklifts etc All conveyors of system materials have to be firmly installed The system is composed of several components the installation procedure consists of laying them out checking them connecting them to the power and air supplies and then joining them to each other and to the production machine Installation procedures Unpacking the Graviman components Checking the weighing unit of each channel for damage on delivery Mounting and calibrating the Load Cells Mounting the holding tanks Mounting the optional material loaders Mounting the Graviman system onto the throat of the production machine 2 1 1 Top Flange holding tank flange Suction loaders and other material feeding equipment can be attached to this flange using suitable adapters if needed Top Flange 2 1 2 Bottom Flange The flange should be bolted to the throat of the production machine usually with a suitable adapter An optional magnet chamber with a slide gate a drainage outlet and a custom made bottom flange for the machine can be supplied 2 2 Installation and Checking procedure 1 Unpack the Graviman components and lay them out in the order that they will be when assembled Check for missing components 2 Visually check all components for delivery damage pay special attention to the load cells For each channel 3 Place the dispensing unit on the floor standing
17. e where the system measures the capacity of extruder b Automatic mode where the system dictates the required RPM for the desired capacity 12 4 4 1 Manual mode operation In manual mode the extruder RPM is set by the user The Graviman monitors the capacity The Graviman switch to should always be in lt auto gt position The values of EX_1_ON EX_1_GRAV_1_RPM_AT_10V and EX_1_GRAV_1_Act_RPM should be always update to reflect system position Turn on the bit EX_1 Manual_mode Refer to section 6 for full detail EX_1_Actual_capacity will show the total capacity of extruder main grav and grav 2 Enter the desired percentage of the additive to EX_1_GRAV_2_Set_Percentage The percentage of the main material will adjust itself automatically to complement to 100 The accumulators EX_1_GRAV_1_Accumulator and EX_1_GRAV_2 Accumulator will show material amounts To reset Accumulators turn on the bits EX_1_GRAV_1_Reset_Total and or EX_1_ GRAV_2 Reset_Total for one second 4 4 2 Auto mode operation In Auto mode the Graviman receives the desired capacity through the CLK and sends back the set RPM Enter the desired capacity to EX_1_GRAV_1_Set_Capacity Enter the desired percentage of the colour channel material GRAV 2 EX_1_GRAV_2_Set_Percentage Turn off the bit EX_1_Manual_mode Copy the EX_1_GRAV_1_Set_RPM to extruder drive to get to the desired capacity 13 5 Unloading and cleaning the system
18. ear The screw is covered by a plastic cap which should be removed first Turning the screw clockwise will increase sensor sensitivity and counter clockwise will decrease sensitivity Note It is a common error to turn the cap instead of turning the calibration screw This is because the cap has the shape of a screw itself Be sure to pull out the cap first 6 2 1 Tuning procedure 1 Make sure the sensor doesn t have any raw material in its vicinity 2 Increase sensor sensitivity until the LED turns on 3 Slowly decrease sensitivity until it turns off 4 Decrease sensitivity by another half a turn 15 6 3 Load Cell calibration Calibration should be checked after replacement of any part involved in weighing Load cell amplifier or analog card It is recommended that a calibration be performed on a regular basis as scheduled by the customer Each weigh unit must be calibrated separately During the calibration procedure three tests are performed e Hysterasis Test Ensures that there s no friction in the load cell and weighing bucket e Calibration Test Ensures the correct ratio used by the unit to convert from the load cell voltage output to the actual displayed weight e Linearity Test Ensures the linearity of the load cell There are two important considerations to be taken into account 1 Each of these tests must be performed in order to ensure proper functioning of the unit 2 There s no point
19. ers allow adjustments and calibrations to be performed Each channel has a number monitoring parameters Ex_1 is the depiction of Extruder 1 in the parammeters replace 1 with the true Extruder number 6 5 1 Filling the Graviman Material in the weighing bucket is constantly decreased in relation to screw feeder throughput The pneumatic shutter is automatically opened in order to refill the bucket every time material dwindles 1 5Kg All calculations are suspended during the fill cycle because the measured weight doesn t reflect screw throughput During the critical fill cycle the system controls the screw speed using previously accumulated data The data from the beginning of a fill cycle and the data from the end of a fill cycle should allow at least 30 seconds of uninterrupted operation between one fill cycle to the next EX_1_GRAV_1_Hopper_weight Continuous hopper bucket weight display resolution 1g EX_1_GRAV_1_Close_Leve End of weighing bucket fill cycle Recommended value 3 000Kg EX_1_GRAV_1 fill level Start of fill cycle Recommended value 1 500Kg 18 6 5 2 Calculation Thresholds Screw throughput is not calculated continuously A number of statistical tools assist in determining the sampling timing and rate of material weight and screw revolutions needed to perform the calculation and build the control model The machine operator can determine basic values that affe
20. essenaes 14 6 MAINTENANCE AND SERVICING sseessessesessesesssesessoscososeoeeseeeseosessososoecoseeesessesoesossoseoseseese 15 6 1 TEACHING ADDITIVE MATERIAL PARAMETERS GRAVIMAN 2 cscsscccsesceeseseeeceescessaeeeeeeeseesees 15 6 2 TUNING THE MATERIAL PROXIMITY SENSORG ssssssssceeseseseeceeeceseseseeeeeescesseseeeeeescesseaaeeeeeseeeaaes 15 E EA ORATE AEE AEE A AE seo cdo E E 15 6 3 LOAD GELL CALIBRATION aroase esros EEEE ris CEEE EE SENEE EENEN TETEE EEE E EETA res 16 6 3 1 Calibration procedur irinn inne aea AEEA AE EE angen AEA R ER OE Ei 17 6 4 AMPLIFIER CARD TUNING ccccesesscceeesceeseseeeceesceeseaeeeecessseseseeeeeeseseaeeaesesceesesaeeeeesceeaaaeeeseeeeesens 18 6 4 1 Tuning proCedure idad dsd 18 6 5 GRAVIMAN MODELING METHOD OF CONTROL ccccccessseseceeeceseseseeceeesceeseseeeeeeeeeseeseaseeesseesaes 18 6 5 1 Filling the Gravina nis ida tii 18 6 5 2 Calculation Thresholds rnein AA aa ia 19 6 3 3 Control Modeline results uta tit tabs 19 7 TROUBLESHOOTING cscssssssssssssssscssssssssssscssssecsscssssssssessssscsscssessssscsssssessesseseesscssssoeses 21 AA fubesehiobss deca bade E A E 21 74d EX1 LOW material level IN hopper ravi iconos skin cts inane sian 21 7 1 2 EX_1_LOW_umaterial_level_IN_grav_1 EX_1_NO_material_IN_grav_l oo 21 7 1 3 EX1 Screw Capacity 1 top MiB c cias cados ia 22 7d ABR 1 Screw Capacity 1 t00 areas 22 741 3 EX L oray 1 WEIGHINGOMOP citan aa 22 710 AR A S
21. for a given screw and material This value has to be learned Run the screw without interruption and collect some typical results multiply by 1 5 and type onto the screen EX_1_GRAV_1_MIN_SCREW_CAP Typical minimum for a given screw and material This value has to be learned Run the screw without interruption and collect some typical results multiply by 0 75 and type onto the screen 20 7 Troubleshooting During alarm conditions suitable bit will turn on Multiple alarms can be displayed Each Graviman has alarm word EX_1_GRAV_1_Alarm_word EX_1_GRAV_2_Alarm_word The alarm bit will be on as long as the alarm is active 7 1 Alarms 7 1 1 EX_1_LOW_material_level_IN_hopper_grav_1 Meaning Material level in the holding tank is underneath the sensor Possible causes 1 Tank loader malfunction 2 Source silo is empty 3 Tank sensor faulty Action 1 Check loader and pipes Is the loader switched on Is there a blockage or leakage 2 Check vacuum motor Isolating switch off Tripped overload 3 Check source silo for lack of material or blockage Is the material moist 4 Make sure the air pressure is within 6 8bars 5 Check and tune the tank sensor see section 6 1 7 1 2 EX_1_LOW_material_level_IN_grav_1 EX_1_NO_material_IN_grav_1 Meaning No material in the weighing bucket Possible causes 1 Tank loader malfunction 2 Source silo is empty 3 Tank sensor faulty Action
22. ice hatches in the housing facilitate periodic checking and cleaning of the bucket e The shutter controls weighing bucket filling e The unit continuously tracks the material flowing through the system 4 1 2 Principles of operation At startup the system controller PLC checks the amount of material in the weighing bucket and fills it up as needed by opening the pneumatic shutter The weigh unit provides the PLC with continuous weight readout During work when the material weight in the weighing bucket is reduced to a predetermined minimum level the pneumatic shutter is opened and the bucket is refilled The PLC calculates throughput by using weight data and screw feeder RPM from the production machine 4 2 Creating a Continuous Dosing System Linking several Graviman units and feeder screws to a central Graviman unit and pipe creates a continuous dosing system 4 2 1 Dosing system Operation The system controller calculates the throughput for each screw feeder using data from the continuous weigh unit Each screw feeder is fixed to a Graviman weigh unit making closed 11 loop control a possibility The central system controller uses loss in weight and screw feeder RPM in order to calculate the percentage of screw rotation for each channel 4 2 1 1 Screw feeder compatibility Each screw feeder in the dosing system has to be able to cope with its intended throughput The throughput for each channel is a function of batch c
23. omposition material density and system throughput 4 3 The Graviman as a controller The Graviman system can perform different control jobs on demand 1 Production machine throughput control The machine operator enters the requested throughput in Kg hr The system will vary machine screw revolutions as needed 2 Product weight control weight per meter The machine operator enters the requested weight per meter The system will control machine screw revolutions or line speed in order to maintain the products weight per meter 3 Layer control Each extruder in the production line contributes its proportion of material as dictated by the product Note The systems are controlled using data tables transfered by the CLK The following example words are for the first extruder A The extruder index numbers at left differes from extruder to extruder Take care to choose the appropriate paramters when servicing each system in your line 4 4 Line Operation using main plc and Graviman s Each Extruder uses 2 write chanel for control orange for example EX_1_GRAV_1_Control_word CHANNEL 2000 100 Write Data memory violtet for example EX_1_GRAV_1_SetdR INT D4000 100 Read only data memory for example EX_1_GRAV_1_Last_dR INT D4700 2 read chanel for and alarm for exmple EX_1_GRAV_1_Alarm_word CHANNEL 2014 refer to attached CX example program for address details The system has 2 modes of operation a Manual mod
24. on its bottom flange 4 Mount the load cell to the external chassis using the bolts on the load cell The load cell sits on a 6mm thick spacing plate Make sure the weighing hopper is at the middle of the chassis and isn t touching anything Tighten the bolts 5 Mount the holding tank extension with the material level sensor if it has been packed separately 6 Mount the optional material loader to the top flange refer to section 2 1 1 7 Supply air pressure dry air 5 7 bar using 6mm hose 8 Make sure the pneumatic valve is Closed an electrical signal to the solenoid should open the valve 9 Check weighing bucket load cell calibration refer to section 6 2 General 10 Mount the Graviman unit in position using the bottom flange and a suitable adapter refer to section 2 1 2 11 Connect 230V 50 60Hz single phase mains power to the N L and Ground terminals in the junction box Make sure the power line is suitably protected 12 Connect All ple to CLK network 3 1 5 CQM1H series Wired Controller Link Unit pr Plc Node D m6000 Indicators Refer to p 39 and 218 ber in Extruder ml LED indicators that display the Unit and network status num NODE No ww 17 Clk network number AA oe ens ma a cas weakens Y Controller Link Network is set in 2 digit decimal gt E Baud rate switch Refer to p 64 Line main 10 Not used ddim me
25. terial has several parameters in the system The main channel parameters are set by the user Additive parameters are lerned by the system automatically by the channel at teach mode This allows the user to change material or screw type easily 6 1 Teaching additive material parameters graviman 2 1 Open additive middle drain 4 screws and mount a box under the opening Make sure the cleaning and test covers are closed and additive is present Move Graviman 2 selector to lt CLOSE gt position E NR IS Press the orange push button for 3 seconds until button lamp blinks The screw starts turning at full capacity and measures the capacity per revolution this value is displayed in the EX_1_GRAV_2_ Last_Screw_Capacity Operator can monitor it to make sure the value is steady 5 After about 30 60 seconds procedure will end The EX_1_GRAV_2_S_D_Screw_Capacity Standard deviation value will drop below 8 and the screw will stop rotating 6 Ifthe operator wishes to end it earlier the orange push button should be pressed once more 6 2 Tuning the material proximity sensors These capacitive sensors alarm when the level of material drops They are connected to the PLC as Normally Closed contact This means that they activate the input to the PLC when the sensor isn t sensing material The LED on the sensor s rear goes ON whenever the sensor detects material Sensor sensitivity is calibrated using the small screw on the r
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