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R,9DIME 200E series 5~ winchester disk drive user manual

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Contents

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2. WCR is the write current return line which can turn off the write current 8 MOTOR SPEED The motor speed control board layout and schematic are CONTROL BOARD given in Figures 25 and 28 This board provides the following circuit functions DC motor speed control stepper motor drive circuits solenoid brake power supply track zero transducer power supply and output termination 8 1 Drive motor speed Speed control of the drive motor is achieved using a phase control locked loop P L L technique The drive motor rotates at 3600 rev min and generates two feedback pulses per revolution from an internal Hall effect IC This results in a TD OT ger TT ar Ten RODIME 120 Hz feedback signal which is phase locked to a reference signal generated from the microprocessor crystal oscillator on the master electronics board speed variation of less than 0 1 is achieved The Address Latch Enable A L E signal from the microprocessor is used as the reference This signal REF CLK frequency 733 KHz is divided by 6144 using ICT and 1C2 to give a 120 Hz input to the phase frequency detector 1C3 The other input to 1C3 is the feedback signal from the motor Hall sensor The output signal on 1C3 pin 8 is a DC voltage proportional to the phase difference between the two input signals R4 R18 C2 and IC4 form the electronic compensation network that ensures the stability of the control loop The resultant signal on IC4 pin 7 driv
3. Not used Fault Code 9 1001 Not used Fault Code 10 1010 No index Fault Code 11 1011 Motor not up to speed Fault codes 1 2 3 5 10 and 11 are monitored during the initial power up sequence of the drive The remaining codes namely 4 6 and 7 are constantly monitored during normal operation All fault codes are latched by the processor and the drive must be restarted to clear Codes 3 4 10 and 11 generate an interface WRITE FAULT as do those fault conditions leading to code 7 From power on to drive READY the microprocessor performs a number of checks and calibrations on the drive Should any of these checks fail the drive will not come READY and the microprocessor will flash the appropriate fault code on the front panel The power up routine is shown in Figure 19 3 2 1 Codes 10 11 The microprocessor checks for an INDEX pulse Hall sensor output from the DC motor If this does not occur during a period of 8 seconds then fault code 10 is displayed Since this condition is likely to be the result of the DC motor not starting the microprocessor attempts to reduce head disk static friction during the period of 8 seconds by moving the positioner RODIME Note that a WRITE FAULT condition removes power from the DC motor thus preventing thermal damage The DC motor speed is then checked to within 1 of 3600 rpm Each check takes one motor revolution and during this time the power on LED is flashed at intervals
4. This device would typically be used with an oscilloscope and allows actuator and head media verification for example It may be purchased direct from Rodime and customers wishing to do so should contact the plant in Glenrothes or the appropriate Sales Office There is no preventative maintenance and there are no adjustments on the drive Field repair is restricted to brake and board replacement and selection of the spare Hall sensor Repair to the module can only be effected by use of Rodime special tooling and Class 100 clean room conditions USERS ARE REMINDED THAT REMOVAL OF THE MODULE COVERS WILL RENDER WARRANTY VOID The tools required for field repair consist of Supadriv screwdriver number 1 Pozidriv screwdriver number 2 Box spanner inch AF Hex driver Allen 5 64 inch 015 inch feeler gauge TRACKER exerciser Optional Access to the brake pre amplifier board and motor speed board is achieved firstly by removing the facia then the master board and finally the side brackets 4 2 1 Master board replacement time 5 minutes Using number 1 Supadriv remove 4 screws holding facia and remove from drive Using 5 64 inch Allen key remove the five 5 screws securing the board to the drive and carefully lift the board free of the drive RODIME Disconnect the flat cable connector from the motor speed board Reassemble the replacement board in the reverse order ensuring that the pre amp connector mat
5. TRACKER 35 TRACKER exerciser motor speed board and check SE which simulates a host controller and allows the user to for 14 ohm between J8 6 and A J8 7 38 8 and J8 9 3 i exercise any 5 och Winchester disk drive which operates 3 Ch k J8 5 oe F via the ST 506 interface It is a useful tool for checking a 4 POS c S e i drive which is believed defective or which has been repaired i mt R pon een 5 The TRACKER comes complete with interface connectors 5 Ch us d F 6 for data and control and with a 5V supply connector It imp TO H basically comprises a keypad for parameter and instruction 6 Check beneath motor speed i i input and six LED S for response board for shorts to casting G 7 7 Replace master board and It will perform the following commands retest J 8 Replace motor speed board Recalibrate Seek track to 1023 Select head to 7 Continuous seek between two tracks Key selectable step rate 30 us to 25 ms in 100 us P increments i end retest 1 Check brake operation 2 Check 12V supply 3 Change link on motor speed board to use spare Hall i element Seek demonstration routine random planet satellite Write pattern select 1F 2F DB Hex o e Write erase for one revolution 20 21 RODIME 22 4 REPAIR AND MAINTENANCE 4 1 Tools 42 Procedure e Write erase for one surface head Continuous write e Check index track 2
6. 8 H2 pT H2 m P10 8 HI P10 10 H3 TT P103 P10 8 cri P10 9 P 10 12 72 P10 15 P10 18 Ge P10 21 P10 24 Hae P10 19 HA AKT H6 P10 18 HB co P 10 17 Hes _P10 10 H6 rn P 10 20 H7 10 23 HI 910 22 z 34N9014 JIAIICI RI paeoq 481 dwe 31d 913e 118U9S p1eoq 0J3U09 paads 40 OW 917ELU3YIS 8z 3un9ld JIAICI NI
7. a square wave which has a 50 duty cycle and makes 4 transitions in one disk revolution This is then divided by two and used to trigger a monostable which gives a 200 us pulse once per disk revolution This hardware scheme results in a non unique INDEX that is one of two each 180 apart Normally this would not be significant since INDEX should only be used during a drive format However some controllers require a unique INDEX for reading The following procedure is used to ensure the INDEX is always unique A special data pattern is written by head on one half of track 2 during drive manufacture At power up a comparison is made between the Hall sensor output and the data burst and a unique index is selected If the data burst is not found on track 2 the drive will display fault code 1 Since the uniqueness of the INDEX signal RODIME is only relevant to certain controllers provision has been made to ignore this fault code Cutting link A will cause the drive to ignore the loss of the data pattern Section 9 2 gives details of features designed to protect track 2 from accidental overwrite There are two user definable links on the master board close to the microprocessor Link A This link is cut to circumvent the fault caused by the loss of the INDEX calibration track See section 6 6 Reset link When this link is inserted J2 pin 5 is connected to the RESET pin on the microprocessor This will allow an int
8. drive fault codes 4 6 and 7 operation may be displayed 3 3 1 Codes 4 6 While the processor is waiting for a step pulse from the interface it continuously monitors the DC motor speed Should the speed vary from nominal by more than 10 or 5 fault code 4 will be displayed The processor will not allow a step pulse to be received while WRITE GATE is true This is considered to be a catastrophic controller fault The drive returns WRITE FAULT status and displays fault code 6 3 3 2 Code 7 WRITE FAULT On receipt of a WRITE FAULT interrupt from the drive s hardware detection circuitry the processor latches this condition delays for 2 seconds and samples the hardware input to check if the WRITE FAULT condition still exists If it does fault code 7 is displayed If not the processor enters the power up routine thus setting the actuator to track zero See Figure 21 In the above sense fault code 7 represents a static WRITE FAULT status There are nine fault conditions which cause WRITE FAULT to be true One is defined above in 3 3 1 These are related to read write heads namely no write current in any head when WRITE GATE and DRIVE SELECTED are both true e more than one head selected no write data transitions when WRITE GATE is true One relates to the DC supply namely e 12V supply lower than about 10 0V The remaining four are abnormal motor conditions as detailed by fault codes 3 4 10 and 11 ROD
9. emphasised by the fact that there are no mechanical adjustments Several engineering features are subject to patent application and these are listed in Appendix 1 Full specifications of the RO 200E series disk drive are given in two documents PRO 0033 Product specification INT 0034 Interface specification 1 2 Specifications A summary of the important performance parameters is given below Product specifications Models RO 201E 202E 203E 204E Disks 1 2 3 4 Heads 2 4 6 8 Unformatted capacity M bytes 13 33 26 66 40 00 53 33 Formatted capacity typical Per drive M bytes 10 49 20 97 31 45 41 94 Per track bytes 8192 Per sector bytes 256 Sectors per track 32 Cylinders 640 Transfer rate M bits s 5 Seek times ms including settling Track to track 8 Average 55 Maximum 130 RODIME Average latency ms 8 3 Flux reversals per inch max 10200 Tracks per inch 600 Rotational speed r p m 3600 Power requirements DC only SV 2596 at 0 65A typical see para 2 5 12V 15 at 2A typical 1096 4A motor start Dimensions inches 8 00 x 5 75 x 3 25 Operating environment 10 C to 50 C 1096RH to 85 RH non condensing Vibration Operating gt 006 inch displ 5 60 Hz 1g pk accin 60 500 Hz Non operating 040 inch displ 5 30 Hz 2g pk accin 30 500 Hz Shock Operating and non operating without transit lock 8g pk less than 10m
10. i t m Lt Berate Lt Brake Din K wc ot wl disk hub Breather fie g Disk stack WIL L Speed board Master board E Mounting 4 bracket Base casting D Fa Thermal compensation Disk chamber thermal loop 3 b c d Drive dra thermal loop e f g FIGURE 12 for a given temperature rise A c lt A a Ab and Ad therefore r w gap tends to move outward from track centre wt Ae gt A f ma g therefore ange tend to decrease causing a clockwise rotation of the r w gap back towards centre RODIME FIGURE 13 Board interconnections To Recording Heads Flexible Circuits Pre amplitier Velocity Sensor Master Electronics 20 Way Data E 8 8 S UJ To Host To Host RODIME gt RODIME FIGURE 14 Read channel signals FIGURE 15 Read Write data timing Orive MFM Write Data Label Description Min Typ Max Units E ty Select to Read Data 5 us t2 Write to Read Recovery 5 us t3 Read bit cell 200 ns t4 Read Data pulse width 25 200 ns ts Write Gate true to Write Data 400 ns ts Write Data to Write Gate False 400 ns ee grin t Write bit cell 200 ns tg Write Data pulse width 25 ns 3717 Phase Curro Driver B Pius MWonding 3717 Phase C r sent Driver 22 z lt z pau ef 3 Y 2 V limas tom Cl atra de eg SR NN SORGE NIGEL E O M IV D MIC NM M ZOO EE SAT i a
11. in the microprocessor firmware and is described in section 3 The other which is implemented in hardware is described in this section Three drive faults are detected RODIME 6 4 1 Write Unsafe WUS This signal is transmitted from the pre amplifier board and is gated through an exclusive OR gate with RM It is high when a pre amplifier write fault has been detected or when the pre amplifier is in the read mode 6 4 2 Low 12V rail 1C9 pin 4 has a 4 3V reference voltage level established from D3 IC9 pin 5 monitors the 12V rail and when it drops to 10 0V IC9 pin 2 will go low This condition is wire OR ed with the Write Unsafe condition and when low signals a hardware WRITE FAULT to the microprocessor 6 4 3 Low 5V rail IC9 pin 13 will go high if the 45V rail is less than 4 3V In this condition RST will be low which will hold the microprocessor in a Power up reset state Also WCR will be high which will turn off the write current on the pre amplifier board Stepper motor control is achieved totally by firmware in the 8049 microprocessor See section 9 1 Eight lines from the microprocessor control the stepper motor drive circuits on the master electronics board Figure 16 illustrates the connection between the microprocessor the drive circuits and the stepper motor via the motor speed control board 6 5 Stepper motor circuitry The stepper motor has a two phase bipolar winding configuration and a velocity sensor
12. mounted externally The windings are driven by constant current drivers mounted on the motor speed control board The magnitude and direction of current is controlled by the circuits on the master electronics board The direction control is direct from the microprocessor using the signals APH and BPH The magnitude can be set at one of two levels high or low and is defined by the singals AVR and BVR Using these four signals an 8 step switching sequence can be obtained as shown in Figure 18 35 RODIME 36 6 6 Index The velocity feedback from the velocity sensor is used for damping and is picked up from one of two coils depending on cylinder number VFA and VFB It is added or subtracted true or inverted depending on the step in the switching sequence and direction of travel This is controlled by four lines from the microprocessor AFB AFB BFB and BFB The signal VDS defines which velocity sensor coil is used and also switches REDUCED WRITE CURRENT RWC on the pre amplifier board The transition occurs at cylinder 210 A position settled signal POK is derived from a window comparator monitoring the velocity feedback and is used by the microprocessor to determine SEEK COMPLETE INDEX is an interface signal used to mark a fixed reference point relative to the disk The Rodime drive does not have a separate INDEX transducer but instead uses the output of the Hall sensor inside the DC motor This sensor output is
13. nearest the terminator pack 11 RODIME 19 25 Power requirements E Similarly for drives 2 3 and 4 Only one pole should be in the closed position All daisy chained drives should have the line terminator pack removed except for the last drive in the chain All drives are supplied for single usage that is pole 1 is closed and the terminator pack is present See Figure 1 Note that in the multiple drive configuration all data interface lines are radially connected to the host Figure 8 shows a four drive configuration The drive requires DC voltages only CURRENT ES Peak During Power up 5V 5 0 65A No damage will result if power is applied or removed in any order However to avoid tripping the fault detection circuitry two conditions must be met 2 5 1 BV risetime must not exceed 1 second 2 5 2 12V must follow the SV within 5 seconds if the 5V is applied first 2 5 3 When checking the power supplies the following loads should be used For the 12V supply the power up current may be measured using a standard load of 3 ohms in series with 1 mH and the operating current may be measured using 5 ohms in series with RODIME 1mH With a 7 ohm resistive load on the 5V supply and the above loads on the 12V supply noise and ripple should not exceed 100 mV peak to peak up to 500 Hz and 50 mV peak to peak from 500 Hz to 5 MHz In operation the maximum rate o
14. of approximately 0 5 second 1f the processor does not see 4 consecutive speed samples correct to 11 within 25 seconds it will display fault code 11 3 2 2 Codes 5 2 When the speed check is successfully completed WRITE FAULT interrupts are enabled The microprocessor then begins the recalibration of the actuat r to track zero The exact routine is shown in Figure 20 Two possible fault codes may occur If flag zero does not go false within 25 steps towards the centre of the disk fault code 5 will be displayed After going false if flag zero cannot then be set true within 800 steps in the out directiori fault code 2 is displayed 3 2 3 Codes 1 3 After calibrating the actuator to track zero the processor initiates the routine for selecting the correct INDEX pulse see section 6 6 for an explanation of INDEX The actuator is moved to track 2 to find the index data burst on head and so select the corresponding Hall sensor phase thus establishing INDEX Failure to complete this operation results in fault code provided link A is present and is ignored if link A is cut The actuator is then re positioned on track zero and a final check made on the DC motor speed again to 11 Should this fail fault code 3 is displayed At the successful completion of the power up routine READY and TRACK ZERO are both set true and the head selects are enabled 15 RODIME 16 3 3 Fault codes during During normal operation of the
15. of spares Repair services Return of drives under warranty RODIME RODIME PART B list of diagrams product description Appendix 1 Patents 44 Appendix 2 Write Data pre compensation scheme 44 Appendix 3 Format recommendations 45 5 MECHANICAL DESIGN 5 1 General Figure 1 Drive outline showing connector positions 49 5 2 Rotary actuator Figure2 J1 Connector control 50 5 3 Head track positioning Figure 3 J2 Connector data 50 accuracy Figure 4 J3 Connector power 50 54 Airflow and filters Figure 5 Control and power bus 51 x Figure 6 Data bus 52 2 0 Thermal cormipensanon Figure7 Mounting details 53 5 6 D C motor and brake Figure 8 System with four drives 54 Figure 9 Wiring of spare hall sensor 55 6 MASTER ELECTRONICS Figure 10 Non planar section of RO 204E 56 BOARD 6 1 Read data channel Figure 11 Airflow and Filter system 57 62 Write data interface Figure 12 Thermal compensation 58 63 Drive E eee es Figure 13 Board interconnections 59 Figure 14 Read channel signals 60 6 4 Fault detection Figure 15 Read Write data timing 61 6 5 Stepper motor circuitry Figure 16 Stepper motor drive configuration 62 6 6 index Figure 17 Step pulse timing 63 6 7 Links Figure 18 Stepper winding switching sequence 64 Figure 19 Power up flow chart 65 Figure 20 Recalibration flow chart 66 EE Figure 21 Write fault flow chart 67 BOARD Figure 22 a Step wait loop 68 Figure 22 b Single track seek and slow mode D 8 MOTOR SPEED l Figure 22
16. IME In practice it is likely that the vast majority of WRITE FAULT conditions are caused by power supply transients Thus the 2 second delay and re check allows a fast transient to be recognised but the condition is not latched if the re Check is successful The controller will receive TRACK ZERO and READY status and can repeat the command which had to be interrupted A table showing likely causes of the fault codes is given below The simplest action to take is that of replacing either the master board or the motor speed board and verifying if the fault code persists However a set of diagnostic routines is presented which determine more accurately the cause of each fault code A voltmeter or oscilloscope and the TRACKER exerciser see section 3 5 are needed for this investigation The causes of fault conditions other than those given by the fault codes may be more difficult to trace In practice the most likely sources of trouble are a power supplies not meeting specification and b step rates outside the drive constraints section 9 1 This presumes that the host controller meets the requirements of the Rodime interface specification INT 0034 3 4 Fault diagnosis In any event it should be verified that the shipping label is removed the connectors are clean and properly attached the interface terminator is present or absent according to the configuration the drive chassis is clear of any system metalwork the DC pow
17. If the spare Hall element is to be connected this is achieved by removing the link on the motor speed board and reconnecting it as shown in Figure 9 Reassemble the motor speed board in the reverse order ensuring correct polarisation of connectors check that the ground contact is correctly positioned between the motor speed board and the casting s 4 24 Pre amplifier board replacement time 30 minutes Remove the master board and side brackets as described in 4 2 1 and 4 2 3 Desolder the flexible cables from the pre amp board using solder wick and a fine tipped soldering bolt maximum temperature 300 C Care must be taken to minimise the heating of the flexible cables Remove the two 2 screws securing the pre amplifier board to the casting and remove the pre amp board Fit the replacement board to the casting using three 3 nylon washers behind each screw position Place the flexible cables over the pins on the board and solder using a fine tipped bolt RODIME Complete the reassembly as described in 4 2 3 4 2 5 Verification The Rodime hand held TRACKER exerciser is a useful tool for verification of a repaired drive prior to final syst ms use This device is more fully described in Section 3 5 It should be emphasised that the following figures are 4 3 Spares holding recommendations only and that it will be up to each individual customer to decide upon the appropriate spares holding Description
18. Part No Drives on site 1 99 100 250 gt 250 Master board assembly ASY 5118 1 2 5 Speed board assembly ASY 5083 1 1 2 Pre amp board assembly ASY 5116 1 1 1 Failsafe brake assembly ASY 2072 1 1 2 Other spare parts such as bracket facia assemblies terminator packs ground tabs and consumable items such as warning labels are also available Spare parts for use as a customer spares holding may be 4 4 Purchase of spares purchased directly from Rodime or from Rodime appointed distributors Spares may also be purchased on an exchange basis under which Rodime will supply a new or refurbished sub assembly making a financial allowance on the returned unit Price lists may be obtained from Rodime its sales offices or authorised distributors DA RODIME 4 5 Repair services Rodime operates a repair service under which drives will be repaired for a standard service charge For drives which are out of warranty when this service is required Rodime should be informed in writing of the suspected defect If the drive is to be returned a Return Authorisation number will be given The drive should be packaged in the original shipping container and returned to Rodime or to the distributor from which the drive was purchased together with a full description of the fault condition If the original packaging has been mislaid a suitable container may be purchased from Rodime or the distributor _ Rodime cannot assume any r
19. RODIME 200E series 5 winchester disk drive user manual RODIME 200E series 5 winchester disk drive user manual P N USMOO38 Revision A Rodime PLC Nasmyth Road Southfield Industrial Estate Glenrothes Fife KY6 2SD Scotland Tel 0592 774704 Telex 728217 Rodime PLC 25801 Obrero Suite 6 Mission Viejo CA 92691 Tel 714 770 3085 Telex 683466 Tha document and the information herein 4 proprietary to F odime P L C No part of tha information may be duobcsied vevested or thout the peor written content of Rodime P L C disclosed wii This ument 11 subject to change without notice right Rodime P L C 1983 r ene o TT At H M e RODIME The purpose of this manual is to provide the user of the RO 200 series disk drive with more technical help and information than is available in the product and interface specifications However it should be emphasised that these latter documents PRO 0033 and INT 0034 are definitive Rather this manual gives practical advice on drive usage as well as engineering background on function and design Part A User Guide introduces the drive in section 1 and lists controller suppliers Section 2 gives information on installation into a system Powering up the drive description of fault codes and assistance in trouble shooting are given in section 3 while section 4 is devoted to repair and maintenance Part B Product Description is aimed at providing a
20. and transmitted to the pre amplifier board as RAW Precompensation of write data is recommended and a preferred scheme is shown in Appendix 2 The compensation applies to the centre bit of each five bit pattern The amount of Compensation should be 10 to 12 ns and it is recommended it be applied to all cylinders All input lines on the control interface are terminated by a 220 ohm resistor to 5V and a 330 ohm resistor to logic ground The input line receivers and output line drivers are 74LS244 buffers with tri state outputs 6 3 1 Input lines WRITE GATE and HEAD SELECT 0 1 2 are hard wired to their appropriate circuits on the master electronics boards DIRECTION IN and STEP are connected to input pins on the 8049 microprocessor since the control of the stepper motor is achieved totally through firmware 6 3 2 Output lines SEEK COMPLETE TRACK ZERO and READY are generated by the 8049 microprocessor INDEX is derived by dividing the output from a Hall sensor on the drive motor by 2 since two pulses occur per revolution of the motor The width of the output pulse is set to approximately 200 ps before transmission WRITE FAULT is set true if any of the drive fault conditions occur as described in section 3 3 DRIVE SELECTED is set true if the DRIVE SELECT signal from the host corresponds with the drive select switch setting on P9 and if the drive is READY Two modes of fault detection are used in the drive One is implemented
21. c Ramped seek modes 70 CONTROL BOARD 8 1 Drive motor speed control Figure22 d Final step routine 71 B2 Stender motor drivacirculf Figure 22 e Adaptive settling routine 72 Figure 23 Master electronics board assembly 73 8 3 Brake Figure 24 Pre amplifier board assembly 74 8 4 Track zero transducer Figure 25 Motor speed control board assembly 75 Figure 26 a d Schematic Master Electronics board 76 79 9 MICROPROCESSOR 9 1 Stepper motor control Figure 27 Schematic pre amplifier board 80 6 2 Protection of index Figure 28 Schematic motor speed control board 81 selection track or RODIME 1 INTRODUCTION 1 1 General PART A user guide The Rodime RO 200 series of 5 inches 130mm Winchester disk drives provides fast access data storage for use with small business computers terminals and microprocessor based systems There are four models in the series RO 201E RO 202E RO 203E and RO 204E containing 1 2 3 and 4 magnetic disks respectively and ranging in total data storage from 13 to 53 Megabytes The drive outline is shown in figure 1 The drive is a microprocessor based device which receives and transmits MFM modified frequency modulation data seeking the appropriate track in response to step commands across the disk control interface The drive is soft sectored and is connected to the host system via a disk controller which is responsible for formatting MFM encode and decode to NRZ block addr
22. dback signal by a factor of 20 Components R7 R8 C6 C7 L1 L2 C53 L5 L6 form a fifth order low pass Butterworth filter with a characteristic frequency of 4 5 MHz The second 592 C2 is configured as a differentiator and transforms the peaks of the readback pulses to zero crossings which are detected by the zero crossing detector IC3 The output signal on IC3 pin 1 is high when the input signal is positive and low when negative IC3 pin 10 provides a negative pulse of duration 100 ns for every zero crossing on the input signal These two signals are used as the data and clock inputs to the D type flip flop ICA This connection provides a time domain filter which will reject zero crossings occuring at less than 100 ns intervals The exclusive or gate IC5 generates a pulse for every edge output from IC4 pin 5 using the delay generated by the series connection through the elements of IC6 and IC7 The signals MFM READ DATA are transmitted to the host for decode Figure 14 illustrates a typical readback signal at various stages in the read channel Figure 15 shows read write data timings Write data from the host is received on the lines MFM 6 2 Write data interface WRITE DATA This differential signal is transmitted to the pre ampiifier board as the single ended signal WDI using the line receiver IC7 33 RODIME S 6 3 Drive control interface 6 4 Fault detection The signal WRITE GATE from the host is inverted
23. e Sunnyvale California 94086 408 773 4200 408 735 1340 Western Western Digital Corp Newport Beach California Digital 9266 714 557 3550 WD 1000 DTC 510 Data Technology Corp 2775 Northwestern DTC 520 Parkway Santa Clara California 408 4960434 Konan Konan Corp 1448N 27th Avenue Phoenix David Arizona 85009 800 528 4563 Junior Each drive is accompanied by a map indicating the addresses of sectors which should not be used This map label is fixed to the base casting wall These illegal sectors have been identified during unit test in the factory and contain a repeatable disk defect greater than one bit in length No such illegal address will exist in cylinders O 1 and 2 An illegal address is specified by cylinder head and sector It should be noted that the format used for this purpose is 33 sectors of 256 bytes each The maximum number of illegal addresses is Model Number 201E 202E 203E 204E Max number of illegal addresses 4 8 12 16 RODIME 2 INSTALLATION 2 1 Shipping lock The stepper motor shipping lock is a label fixed to the top cover of the drive and covering a plastic pulley on the stepper motor shaft thus preventing movement of the read write heads across the disk surfaces This label must be removed prior to power on Warning Once the label is removed the stepper motor shaft _ should never be rotated by hand since this could lead to head disk damage Note This labe
24. e dad ok C gt AVR gt nuta h 14 ent 1 A lt DU 8 cJ gt IBVRI gt GUREN Switches AFB ee L2 BFB ADV Be a u Cos chan Liest dun lt j i ER Mops VEL P c fan o o EEE O annere rr R arr OT ERR RR are rra 749 Microprocessur 62 FIGURE 17 Step pulse timing Step Drrection Label Description Min Typ Max nits D Width of Step pulse 0 5 US to Time between Step pulses 5 5000 us t3 Time from first Step to 40 ns Seek Complete False t4 Direction set to first Step 0 ns ts First Step to direction change 150 us for overlap seek RODIME on ooo mr n 63 RODIME RODIME FIGURE 18 i FIGURE 19 Stepper Winding Switching Sequence Power up flow chart _ Ready False Stepper Motor off Track O False Disable Head Selects High Current VE Direction High Current VE Direction Low Current VE Direction No Low Current VE Direction he tll A Phase B Phase eng Current Current Index y Speed 1 Transition No Yes Yes Go to Track Enable Write fait 2 Faults Data No Se Burst Can 21 ders ve Recalibration flow chart rite fau Write Fault Set Direction to IN Yes Unlatch sample amp latch Write fault Set Direction to OUT Flay Y 800 Phase O Steps Fault iN Set Track DO Display fault ode IR Wait 6 Svoreis Se T
25. ee i lt E RODIME m RODIME FIGURE 22 a FIGURE 22 b Step wait loop Single Track Seek and Slow Mode MIE ke ES RODI Master Electronics Board Assembly 2 gt Em pip T o WH SC m CR T dada Oi 9Qv1Y Nbotemn Vv 002 1 KU ice H S d L End i S E Adaptive Settling Routine FIGURE 2216 RODIIVIE 72 RODIME 75 FIGURE 24 Pre amplifier Board Assembly FIGURE 25 Motor Speed Control Board Assembly 2939009 00000 966909069090 MOUNTING DETAILS FOR Q3 amp 04 MOUNTING TORQUE tb in H 1 MAXIMUM COMPONENT HEIGHT ABOVE PCB TO BE 025 2 CROP ALL COMPONENT LEADS TO 0 040 MAX SENS 4 MOUNT R8 WITH A BODY TO PCE CLEARANCE OF 0 1 1 CROP ALL COMPONENT LEADS TO 0 050 MAX 2 MOUNT Q1 Q2 Q 4 QIO USING 39 PAD 8043 3 MOUNT Q6 USING 40 PAD 8045 NOTES 3 SCH 1 a 9 66 09996 s O G O 220 Gs 05 09 3 D e 9Z 20012 t yy M Map DATA Gerin e o Z eo 3 t e o H et D m o Qo 2 o 3 2 D o D gt o ev A108 ith one s war y 00208 Ha f LB Ice PYM G R Kat WAITE DATA x N MU 1 wr 3 BI Ki o Y 19 t neg A me 1 at mos V 08 e wo 1 D wr a ES Da Lon ur LOG ano M ONO cu mer T este no LOG ano Si Uta 2 t b ov LOG Ong p4seog s21404329 3 J8JSE ILWIS 9 97 34NO14
26. er lines are short twisted pairs and data and control cables are preferably shielded and do not run close to high current switching circuits 3 4 1 For each fault code a possible cause is indicated in the Fault Table by a letter This is used in the Diagnostics Table for idenfification 17 RODIME Fault Table Code 18 Possible Causes Faulty flag zero position Fault in data burst detection circuitry Fault in head or pre amp board Data burst erased Transit lock label not removed faulty stepper lock option if fitted Connector fault between motor speed board and stepper motor flag zero assembly Short circuit between motor speed board and casting Faulty flag zero transducer l Fault in stepper motor control circuitry Fault in stepper motor control circuitry Faulty stepper motor Defective positioner assembly Action Contact service organisation Replace master board Contact service organisation or replace pre amp board Rewrite with TRACKER Remove label check stepper lock solenoid Check connector and or replace motor speed board Reassemble board Contact service organisation Replace master board Replace motor speed board Contact service organisation Contact service organisation Action Possible Causes Brake failure Replace 10 11 No 12V supply Check supply connector Q Faulty DC motor Contact service Hall element organisat
27. er s expense Rodime reserve the right to make a charge for testing and handling under these circumstances 27 R DIME NOTES RODIME PART B product description The important performance and reliability aspects of the 5 MECHANICAL RO 200E disk drive mechanical design may be summarised as DESIGN follows 5 1 General Up to four disks in mini floppy size compatible unit Designed for easy assembly of heads and disks Minimum number of components to maximise reliability Two chamber principle with heads media in one and actuator mechanisms in the other Low inertia positioner for reliability and fast access Geometry designed to minimise head yaw l Drive components designed to compensate for thermal head disk movement DC brushless motor with ferrofluidic seal and integral ventilated hub Breather filter positioned to equalise pressure across DC motor bearing Air flow designed to locate drive components upstream from re circulating filter and downstream from heads media thereby creating an optimum purge cycle The positioning system consists of a stepper motor which 5 2 Rotary actuator drives a tensioned steel band via a pulley The band in turn l moves a drive arm which is attached to a shaft The shaft rotates in a bearing system and moves the head arms across the disk Simplicity of components ensures easy assembly and reduces failure risk The two phase stepper motor operates in a fractional step mode unde
28. erface RESET if J2 pin 5 is held at less than 0 5V fora minimum of 12 5 ps then returned to 3 8V minimum Note that the microprocessor has an internal pull up of 200 Kohm on this line The pre amplifier board layout and schematics are shown in Figures 24 and 27 This board provides a means of connection for up to eight read write heads Two SSI 117 monolothic integrated read write circuits provide the following functions pre amplification of read data write amplifiers head selection write fault detection Each circuit can support four read write heads RDX and RDY are the differential read data signal lines to the master electronics board HSO and HS1 select 1 of 4 heads on each circuit HS2 and HS2 select which circuit is active 6 7 Links 7 PRE AMPLIFIER BOARD RODIME WUS is the write unsafe signal which is low when the chip is writing normally The high unsafe level will be caused by a Head input shorted to ground b Head input shorted to centre tap c Head inputs shorted together d Head input open le Centre tap open f No write data transistions g No write current h Any combination of above 1 Chip is in read mode j Chip is disabied HS2 HS2 Certain lines have been mentioned in the text These are defined as follows e WDI is the WRITE DATA INPUT line HAN is the read write mode select line RWC is the reduced write current line
29. es correctly with the pre amp board and the flat cable connector is correctly polarised 4 2 2 Brake replacement time 10 minutes Remove the master board as described in 4 2 1 but do not disconnect the flat cable from the motor speed board Disconnect the brake connector from the motor speed board Remove the two screws securing the brake to the casting using the number Pozidriv screwdriver and remove brake Position the replacement brake and refit the screws loosely Place the 015 inch feeler gauge between the motor rotor and the brake pad and push the brake body such that the plunger fully depresses against its spring Ensure that the centre line of the brake lines up with the motor centre and lock the screws Reconnect the brake connector Reconnect the power connector ensuring correct polarisation Power up the drive with the master board lying alongside and check that the brake does not contact the motor rotor Power off and check that the stopping time is in the range 5 to 8 seconds Refit the master board as described in 4 2 1 4 2 3 Motor speed board replacement time 10 minutes Remove the master board as described in 4 2 1 23 RODIME 24 Remove the three screws and stand off securing the mounting brackets to the casting and carefully remove the side brackets Disconnect the brake DC motor and stepper motor from the motor speed board Unscrew the rear stand off and remove the motor speed board
30. es the motor via the emitter followers Q1 and Q2 and the power amplifier Darlington transistors Q3 and Q4 A two phase drive motor is used and commutation between the two phases is accomplished using the Hall IC output This signal and its inverse alternatively enables either Q3 or O4 depending upon the phase of the commutation cycle The Hall sensor signal is also sent to the master electronics board where it is divided by 2 and used as the drive INDEX signal A spare Hall sensor output is provided and in the event of output failure the spare may be connected by wire link selection Current in the windings of the stepper motor is controlled 8 2 Stepper motor drive by two constant current drivers C5 and IC6 The magnitude circuit of the current is controlled by AVR BVR and the direction by APH BPH The stepper windings are connected between ACA and ACB BCA and BCB RODIME 8 3 Brake 8 4 Track zero transducer 9 MICROPROCESSOR 9 1 Stepper motor control The signals AOF and BOF hold the drivers in an off condition until the spindle motor is up to speed during the power up sequence Power is supplied to the solenoid brake initially from the 12V rail until it pulls in and the OC motor is up to speed Thereafter power is supplied from the 45V rail via diode D3 to reduce running power dissipation The resistor R18 is a bias resistor for the LED in the opto interrupter A nominal forward current of 30 mA
31. esponsibility for damage incurred to the drive during the shipment and insurance is the responsibility of the customer Rodime will return the goods carriage collect and a charge will be made for any shipping container which Rodime may have to provide Further details of this service may be obtained from Rodime or its authorised distributors 46 Return of drives Rodime Terms and Conditions of Trade include a under warranty warranty for a period of twelve months from date of shipment The procedure for return of drives under warranty is as follows If the drive fails within the first five days of operation please contact immediately the Marketing Department at Rodime or the distributor from whom the drive was purchased pos ee 26 RODIME In the event of other problems Rodime or the appropriate distributor should be informed in writing of the suspected defect If the drive is required to be returned a Return Authorisation Number will be given and the drive should be returned pre paid The same procedure as in 4 5 above applies If on examination the drive is proved defective under terms of the warranty the drive will be repaired or replaced at Rodime s sole discretion and returned to the customer at no charge If the defect is found to be due to mis handling or other causes the drive will be treated as a standard repair and charged accordingly If on examination no fault is found the drive will be returned at the custom
32. ess decode CRC generation and verification and so on Typical format schemes with 256 data bytes per sector and 32 sectors per track can realise an efficiency of about 80 giving formatted capacities up to about 42 MB Dimensions mounting details and voltage requirements DC voltage only are the same as standard 5 inches floppy disk drives The microprocessor is responsible for the control of the stepper motor used for head positioning Fast seek times are achieved by means of programmed velocity profiles and microstepped velocity feedback damping routines Automatic thermal compensation has been designed into the head positioning mechanism A brake is provided as standard for the main DC disk motor and this permits shipment of the Rodime drive in a terminal or system provided it has been mounted in accordance with the correct procedure see section 2 A further solenoid brake for the actuator can be supplied as an optional extra The microprocessor also monitors certain fault conditions in the drive and should one RODIME occur flashes the corresponding fault code on a red LED indicator on the front panel A significant feature of the RO 200E series is that boards are interchangeable without the use of oscilloscopes or other setting up equipment This is made possible by the fact that there are no select on test components and no adjustments on the boards whatsoever This of course in addition gives added reliability which is further
33. f change of the 12V load due to the disk drive is BA ms Two red LED s fixed to the master electronics board are 2 6 Indicators visible through the facia when they are illuminated 2 6 1 The Power On LED is on when the drive is READY with no error condition present It is also used to indicate fault conditions in the drive 262 The Select LED is on when the drive is selected by the host provided the Power On LED is on The Power On LED is positioned closest to the centre of the facia Note that this LED will not come on if the condition 2 5 1 5V risetime is not met since the microprocessor will not receive an initial reset The Power On LED is used to flash error messages should 3 FAULT FINDING certain fault conditions arise on the drive A four bit binary 3 1 Front panel fault code is used long flash logical 1 short flash logical 0 codes with the most significant bit occuring first e g short short long short 2 0010 Fault Code 1 0001 No index track data burst Fault Code 2 0010 No Flag zero Fault Code 3 0011 Motor speed outside 1 tolerance at end of power up sequence 4 7 RODIME 14 32 Fault codes at power up Fault Code 4 0100 Motor speed outside 10 tolerance in normal operation Fault Code 5 0101 Fault Code 6 0110 Flag zero stays TRUE STEP received while WRITE GATE is TRUE Fault Code 7 0111 WRITE FAULT Fault Code 8 1000
34. gal cylinder number the microprocessor ramps down the stepper motor and stops at the last legal cylinder number attainable in the direction requested ie stops at cylinder if a seek is attempted to a negative track and at cylinder 639 if a seek to a cylinder gt 639 is requested This protection operates for all legal step rates in any direction In the event of a failure in the velocity damping system resulting in an undefined settling performance the S microprocessor will initiate an auto recal prior to settling s ek complete Protection of track 2 is considered to be of prime importance and a number of safeguards have been built into the firmware 9 2 Protection of index selection track 9 2 1 All interface controlled seeks beyond track zero are prohibited by the microprocessor At the end of each seek and before SEEK COMPLETE is issued a check is made f either of the following conditions is detected then an auto recal will be executed a Flag zero is detected and the internal track counter is not at zero b The track counter is at zero and flag zero is not true 43 RODIME APPENDIX 1 Patents European fea e Application US Application Title Number Number 81305976 332003 Read Write Head Thermal Compensation System 82302197 373281 Method and Apparatus for Controlling a Stepper Motor 82303263 Generation of Unique Index Mark from the Commutation of DC Brushless Mo
35. ia a 20 pin edge connector P2 J2 The pins are numbered 1 through 20 with the even pins located on the solder side of the board The recommended mating connector is AMP ribbon connector A N 88373 6 DC power is provided by a 4 pin AMP Mate N Lok connector P3 J3 P N 350211 1 mounted on the component side of the board The recommended mating connector is AMP P N 1 480424 0 utilising AMP pins P N 350078 4 A ground connection is provided via a Faston connector AMP P N 61664 1 located on a metal stand off on the chassis between the power and control signal connectors However the DC and chassis grounds are common on the drive and the use of the Faston connector is not essential Wiring should be in accordance with Figure 5 The frame ground of the host system should be properly earthed The following 5 inch Winchester Disk Controllers are known 1 4 Controllers to operate with the RO 200 series disk drive In general any controller which will operate with the RO 100 and RO 200 series disk drives will also operate with the RO 200E series disk drive However the controller must be able to address up to 640 cylinders and set the STEP interval in the nnan nnn 9 RODIME 10 1 5 illegal Address Map range 5 US to 5 ms Further information is available from the Rodime Marketing Department or from the controller manufacturers themselves Xebec Microcomputer Systems Corp PO Box 512 1410 432 Lakeside Driv
36. ing clock Identifies beginning of data field 12 Address Mark Data Field Identifier 1 byte Hex F8 Identifies with previous address mark the beginning of the data field 13 Data 256 bytes of data 14 Data ECC 3 bytes Available for ECC check of the data field 15 Gap 2 bytes of 00 Allows write turn off time when updating the sector data field 46 RODIME 5 0 70 Index Gap The gap at the beginning of index allows for head switching recovery so that sequential sectors may be read without losing a complete disk revolution Minimum length is 12 bytes Hex pattern 4E Normal recommendation is 16 byte lengths Speed Tolerance Gap This gap at the end of the last physical sector before index provides a spindle speed tolerance buffer for the whole track A full track format routine begins and ends with detection of index It is usually a Hex pattern 4E and the actual number of bytes depends on media speed during the format operation Sector Interleaving It is possible to interleave sectors to improve data throughput during typical read write operations by allowing multiple sector transfer within a single revolution 47 RODIME TIMES REPEAT N O ADDRESS FIELD EET jo DATA FIELO MSS 4 14 1 au Field FIGURE A SECTOR FORMAT M ov M MI gt M M PP e gt FIGURE 1 Drive outline showing connector positions FIGURE 2 J1 C
37. ion R Faulty motor speed Replace board Controller Interface Check controller fault connector T Faulty master board Replace Faulty master board U Replace V Faulty pre amp board Replace W SV and or 12V Check supply too low 3 4 2 A numbered set of checks is given for each fault code displayed on the front panel The action after each test is indicated by a number or a letter The number refers to another check normally the next shown for that fault code in this table The letter refers to the determined cause as given in the previous table Test is faulty Yes No 1 Cut link A to let drive vecome ready RODIME Diagnostics Table 19 RODIME RODIME Test is faulty Test is faulty No Procedure Use TRACKER to check on Replace motor speed board 4 Replace master board re write data bursts and retest Test 12V to be in range 11 4V to 12 6V Test BV to be in range 4 75V to 5 25V 2 Replace master board and retest 1C9 14 that flag zero switches and retest between tracks 2 and 5 A 3 3 Use TRACKER to re write Check interface cables date bursts replace link and controller retest 4 D i Check if transit lock label is removed Check stepper lock 2 Remove connector J8 from Solenoid if fitted E 2 Rodime has developed a hand held exerciser the
38. is set to switch between tracks 3 and 4 Track zero reguires the flag to be true transducer interrupted and the correct stepper phase to be selected Note that the opto interrupter and drive components are in the sealed lower chamber and hence protected from contamination and accidental handling damage hte e RODIME 5 3 Head track positioning The requirements of the positioning system are a that tracks do not touch and b that an acceptable signal to accuracy noise ratio is obtained when the same track is overwritten Broadly speaking the first condition determines the maximum track pitch error In the case of the RO 200E drive it relates mainly to the static stepper motor accuracy The second condition relates to the repeatability of the positioning system Thus given a specification for the repeatability tolerance the required mean static step accuracy of the motor can be determined for a given track density The airflow generated by disk rotation causes air to flow 5 4 Airflow and filters from the disk chamber through an aperture into the drive chamber and to return via a recirculating filter This flow system ensures equalisation of temperature during warm up by moving air over all components By positioning the recirculating filter upstream from the heads and the drive components downstream from the heads optimum purge conditions can be achieved The disk hub is designed to ventilate the inter disk spaces f
39. is supplied The resistor R17 is a pull up resistor for the photo transistor which is connected in the open collector output configuration The microprocessor used in the RO 200E series is a member of the 8048 family of single chip processors The particular type used is the 8749 an EPROM version with 2048 bytes of intemal program memory and 128 bytes of RAM The microprocessor cycles at 11 MHz giving an instruction time of 1 36 ps The processor has three main functions 9 stepper motor control interface handling track positioning monitoring It also indirectly controls the DC spindle motor since the 733 KHz ALE signal output from the processor is used as a reference frequency for the P L L Four interface signals are used to control the stepper motor STEP This input signal is used in conjunction with DIRECTION IN to move the stepper motor It is connected to the 8749 T1 pin This is a special input to the microprocessor which is used to clock an interna 10 bit counter This counter is reset prior to each seek Once the 40 a RODIME first STEP pulse is received the processor issues stepper motor phase changes until the number of changes equals the value in the counter At this point the seek is terminated and SEEK COMPLETE is set true after final step damping DIRECTION IN This input is connected directly to an 1 0 pin of the processor It defines the direction of motion of the stepper motor Once
40. l is not present on units which are fitted with the automatic stepper motor lock This lock also releases on application of 12V The drive can accept step pulse intervals over a range from 2 2 Step rate 5 us to 5 ms If the interval is in the range 5 us to 130 us then the drive is operated in the ramped seek mode The seek operation will begin if 32 step pulses have been received or 180 us has elapsed since the last step pulse was received In this mode of operation the access times will vary with step interval The access times quoted in paragraph 1 2 are for a step interval of 10 us If the step interval is in the range 130 ps to 5 ms then the drive step rate will vary with step interval Consequently the access times are not specified Side brackets with tapped holes are provided with each drive 2 3 Mounting and permit base or side mounting see Figure 7 These brackets are fixed to the drive chassis via shock absorbing grommets The drive may be oriented in any axis When installing into an enclosure at least 0 1 inch clearance must be maintained around the entire drive to allow vibration isolation and to prevent obstruction of the breather filter and the creation of ground loops 2 4 Multiple drive configuration Up to four drives may be connected to one host in a daisy chain fashion A 4 pole drive select switch is fixed to each drive See Figure 1 To identify a drive as number 1 close the first pole of this switch
41. lock bit This unique byte is used to flag the start of the sector address field containing the physical sector address and also to flag the start of the sector data field 4 0 Sector Format Example An example of a recommended format for a 256 byte sector is given in Fiqure A A full description of each item is given below 1 Inter Sector Gap 15 bytes of Hex 4E Tolerance gap to allow for disk speed variations 2 Sync Field 13 bytes of 00 Provides VFO lock on prior to data retrieval The minimum number of bytes is dependent on VFO lock up performance of host data separator a da cn RODIME 3 Address Mark 1 byte of Hex A1 with missing clock Identifies beginning of address field 4 Address Mark I D Field Identifier 1 byte Hex FE Identifies with previous address mark the beginning of the address field 5 Cylinder Address 1 byte O to Hex FF The most significant bits in the Head Address field 6 can be used to represent the most significant bit of the Cylinder Address 6 Head Address 1 byte 0 to 7 7 Sector Address 1 byte 0 to Hex 1F 8 Address ECC 3 bytes Available for ECC check of the address field 9 Gap 2 bytes 00 Allows write turn on time when updating the sector data field 10 Syne Field 13 bytes of 00 Provides VFO lock on prior to data retrieval 11 Address Mark 1 byte of Hex A1 with miss
42. onnector Control pe 2 Ale U D 1 05 Nom 05 Nom L 01 Nom 1 7754 01 F Board Thickness 062 007 FIGURE 3 J2 Connector Data d Nom 05 Nom Board Thickness 062 4 007 1 075 1 01 FIGURE 4 J3 Connector Power OOOO RODIME FIGURE 5 Control and power bus Fiat Ribbon or Twisted Pair 20 F1 Max RO 200 Host System A U L NG ee es MENT ll 1 8 DEACERO AAA ea A OE msme GENESE E S EEE PASAN AA ng J1 P1 m 5V0C A DOT am vm E DC JA P4 3 Twisted Par Casting RODIME gt RODIME FIGURE 6 Data bus FIGURE 7 Mounting details A Vented Facia FAC2001 B Plain Facia FAC2107 Orive pS ae ee E A 338 OF 86 3 25 02 010 B 335 A TEA Z Mounting Holes 6 32 UNC 4 on base 2 on each side MFM Write METTI E 18 z DERE IN ETT 187202 3 12 02 B 052 01 RODIME FIGURE 9 Wiring of spare hall sensor FIGURE 8 2 s 3 E gt o r O o same r O O e EN o a a ae IF A BEL Li d Ces A uu DC VC M AA Frame Ground RODIME FIGURE 10 i FIGURE 11 Non planar section of RO 204E Air flow and filter system An Atmospheric Compensation and pressure balance Velocity S Drive band assembly le a Breather filter Stepper motor Base cover A I Angle beel
43. r Rate N lt 5 Stow 1 ms 5 amp N 32 Moderate accn decn ramps 32 lt N lt 150 Fast accn moderate decn ramps 150 lt N lt 639 Fast accn fast decn ramps b Input Step rate 130 us to 900 ps Stepper rate 1 ms c Input Step Rate 900 us to 5 ms Stepper rate variable d Input step rate greater than 5 ms may cause seek errors In the ramped mode of operation the maximum step rate to which the stepper motor accelerates is 7000 steps second The acceleration deceleration ramps chosen are based on the length of seek required This choice ensures optimum access times with defined settling performance In the ramped seek mode ie for input step rates in the range 5 to 130 us the microprocessor will move the positioner assembly before all the step pulses have been received in accordance with the following conditions a Morethan 31 step pulses have been received or b 180 ps has elapsed since the last step pulse was received After moving off and as further step pulses are input the microprocessor makes decisions about acceleration and deceleration on the move This also ensures that access times are minimised 42 RODIME Soft endstop protection is also provided by the microprocessor An internal track counter which is dynamically updated means that the processor is aware of how close the mechanical assembly is to the mechanical endstops at any point in a seek This means that if a seek is requested to an ille
44. r microprocessor control 0 45 per track 5 2 1 Stepper Load The positioner has low inertia to provide 28 N 0 RODIME fast seek times maximum velocity 7000 tracks per second from the available stepper motor power 5 2 2 Yaw The geometry of the positioning system restricts head yaw to a range of only 8 The distribution of this angle is chosen such that the ratio of yaw angle to linear disk speed is approximately the same at outermost and innermost tracks 5 2 3 Bearings The actuator system utilises two half shielded deep groove ABEC 3 ball bearings arranged in a back to back configuration with a dimensional axial preload of 5 Ibf for optimum stiffness 5 2 4 Band The drive band geometry is designed to give symmetry of movement and to minimise band radii and flexing angles The band is etched from stainless steel with a typical tensile strength of 250K psi There is a safety factor of approximately 40 between the breaking stress of the band and the dynamic peak tension End stops restrict over travel should control be lost and will prevent read write heads from either striking the disk hub or coming off the disk 5 2 5 Flag zero Track zero is defined from a combination of a particular stepper motor phase one of eight and a flag mounted on the drive arm This flag is set up using a special assembly fixture to switch on opto interrupter track zero transducer mounted on the base casting The flag
45. rom both ends thus ensuring adequate air flow across the disks The breather filter situated on the top cover is positioned on the disk rotational axis This compensates for atmospheric changes and maintains a pressure balance across the DC motor bearings reducing the risk of ingress of contaminants The breather filter is 99 9796 efficient to 0 5 um particles and the time taken to equalise pressure is less than one second l The recirculating filter is positioned in the drive chamber upstream from the disk chamber This ensures that any particles generated by moving parts are retained by the filter and prevented from contaminating the disk chamber The recirculating filter is 99 efficient to 0 5 um particles giving a purge time of 12 seconds 31 RODIME 55 Thermal comperisation The positioning mechanism is designed to compensate automatically for head to track mispositioning caused by thermal effects The thermal loop in the disk chamber motor hub disk head flexure head arm shaft bearings bearing housing and base casting causes the read write head to move outwards from track centre as temperature rises By careful design of geometry and materials the thermal loop in the drive chamber stepper motor band drive arm shaft bearings bearing housing and base casting causes a counter rotation of the actuator thereby maintaining the heads on track centre See Figure 12 The resulting misposition is about 1 uin per 1 C
46. s max 2 per second Non operating with transit lock 30g pk less than 10 ms max 1 per 10 second Interface ST506 variant of SA1000 see section 1 3 and 1 4 1 3 Connectors The RO 200E drive interfaces to host systems via the ST506 interface which has become an accepted standard for 5 inch Winchester disk drives There are separate connectors for data in MFM code for control lines and for DC power The connector positions are shown ing Figure 1 and the connectors themselves are defined in Figures 2 3 and 4 The corresponding control power and data interfaces are given in Figures 5 and 6 A chassis ground tab is also provided The convention for control is that a TTL logical zeros is true and a TTL logical one RODIME is false Up to four drives may be connected to a host system and each drive is provided with a four hole switch for selection The control lines may be daisy chained but the data lines must be radially individually connected to the host see section 2 l Control signals for the drive are provided via a 34 pin edge connector P1 J1 The pins are numbered 1 through 34 with the even pins located on the solder side of the board Pin 2 is located on the end of the board connector closest to the DC power connector and is labelled A key slot is provided between pins 4 and 6 The recommended mating connector is AMP ribbon connector A N 88373 3 Radial connection of read write data signals is provided v
47. technical introduction to the drive design Sections 5 to 9 deal with the mechanical configuration the function of the electronic circuitry and features of the microprocessor firmware Two appendices list patents applied for and a recommendation to controller designers of a write precompensation scheme Further help is readily available from Rodime customer support engineering and this can be obtained by contacting either the appropriate Sales Office or by direct contact with the main plant iri Glenrothes Rodime s dedicated policy is te ensure customer satisfaction with both the product and its service and in order to maintain this any suggestion for improvement to this manual or our service is welcome and should be made directly to me at the Rodime Plant in Glenrothes Rodime right from the peginning MEL Malcolm F Dudson DIRECTOR OF MARKETING PART A user guide 1 INTRODUCTION 2 INSTALLATION 3 FAULT FINDING 4 REPAIR AND MAINTENANCE 1 1 1 2 1 3 1 4 1 5 2 1 2 2 2 3 2 4 2 5 2 6 3 1 3 2 3 3 3 4 3 5 4 1 4 2 4 3 44 45 46 RODIME General Specifications Connectors Controllers illegal Address Map Shipping lock Step rate Mounting Multiple drive configuration Power requirements Indicators Front panel fault codes Fault codes at power up Fault codes during operation Fault diagnosis TRACKER exerciser Tools Procedure Spares holding Purchase
48. temperature change It is estimated that this would be about 8 10 uin per C in the absence of this compensation mechanism 5 6 D C motor and brake The motor is a brushless 2 phase external rotor DC motor with integral hub and commutation effected by Hall sensor A spare Hall sensor is provided in each motor The motor uses preloaded ABEC 7 bearings and is balanced in two planes to better than 0 25 gm cm A ferrofluidic seal is fitted above the top bearing The disk hub is grounded to the master electronics board via the motor shaft and a button contact The brake is a plunger solenoid designed to stop the motor in 5 seconds and to provide a restraining torque during handling The brake pulls in at 12V and holds off at 5V 6 MASTER The master electronics board layout and schematics are given ELECTRONICS BOARD in Figures 23 and 26 a d This board provides the following circuit functions read data channel and interface write data interface drive control interface fault detection stepper motor control circuit EEE a S es 32 RODIME In addition the master board provides DC power distribution and control to the motor speed control board and the pre amplifier board The interconnections between the various boards are illustrated in Figure 13 Read data from the pre amplifier board is received differentially 6 1 Read data channel on the lines RD and RD The 592 video amplifier IC1 amplifies the rea
49. the first STEP of any seek has been received the microprocessor samples this input and internally stores the result The input is then ignored until the next seek SEEK COMPLETE This status line is driven by a S R flip flop STEP resets the flip flop false It is set true with an output from the microprocessor TRACK ZERO This status line is driven directly from the microprocessor It will be set true when the read write heads are positioned with correct stepper motor phase over track zero false otherwise Velocity feedback is obtained from a tachometer fitted to the endcap of the stepper motor This feedback is employed a to assist in the control of the motor whilst is is slowing down on the fina approach to the desired track and b to control the settling when the motor reaches the desired track This results in settling time being greatly reduced from that which could be obtained under open loop conditions An important additional benefit gained from the use of velocity feed back is that the microprocessor can examine a digitised velocity signal to ensure that the positioner assembly is fully settled before setting SEEK COMPLETE status All step pulses are buffered by the microprocessor Two factors determine the stepping rate of the head assembly the interface step rate the length of the seek 41 RODIME Stepper rate is defined as follows a Input Step Rate 5 us to 130 ps Seek Length N Steppe
50. tor 391150 Damping of Stepper Motor using Non Active Windings AAA 388165 Ventilation System for 82303262 Computer Disc Drive Hub Assembly APPENDIX 2 Write Data Pre Compensation Scheme Data sequence Required write leftmost bit pre compensation of written first centre bit cof of 10 EARLY SOA EARLY 00 1 10 LATE 00 1 11 LATE oil 1 on EARLY por 1101 EARLY 10 01 00 LATE 10 of o LATE 10 1 10 LATE 101 11 11 LATE 1111100 EARLY 1111101 EARLY 44 ___RODIME APPENDIX 3 Format Recommendations 1 0 The following sections describe the general formatting recommendations for the RO 200E series disk drives 2 0 Encoding It is recommended that data be written on the disk using an MFM encode The algorithm to convert from NRZ data to MFM data is as follows For a 1 write a flux transition in the middle of the bit cell for a 0 write a flux transition at the start of the bit cell except when a 0 follows a 1 3 0 General Requirements The format of the data recorded on the disk is totally a function of the host controller The two most common formats allow 32 x 256 byte sectors or 16 x 512 byte sectors to be written on each track A soft sectored format should be used The start of each sector is identified by a unique byte which is written on the disk This byte is normally an invalid MFM code eg Hex A1 with a missing c

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