JUKI SC-921 Instruction Manual
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JUKI SC-921 Instruction Manual

JUKI SC-921 Instruction Manual

Discrete control box
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SC-921
INSTRUCTION MANUAL

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Summary of Contents for JUKI SC-921

  • Page 1 SC-921 INSTRUCTION MANUAL...

  • Page 2: Table Of Contents

    (2) Overlapped stitching pattern ........................ 18 4. One-touch setting ..........................19 5. Production support function ....................... 20 6. Setting of functions of SC-921 ......................23 7. Function setting list ..........................24 8. Detailed explanation of selection of functions .................. 28 9.

  • Page 3: Specifications

    * The electric power is a reference value for the model equipped with the LH-3568A machine head. It differs by the selected machine head. II. SET-UP SC-921 is a discrete control box and can SC-921 control box be used with the DD (direct-drive) system sewing machine head.
  • Page 4 * For the EU-type models, install the reactor box that is supplied with the sewing machine. 1) Connect the terminals of power cord ❶ of the ❷ ❹ SC-921 to reactor-box PCB asm. ❷ and to reactor box mounting plate ❸ . Connect brown wire A to the first connector ❸...

  • Page 5: Installing The Control Panel

    2. Installing the control panel WARNING : To protect against possible personal injury due to abrupt start of the machine, be sure to start the following work after turning the power off and a lapse of 5 minutes or more. 1) Remove side plate setscrews ❶...

  • Page 6: Connecting The Cords

    • As for the details of handling respective devices, read carefully the Instruction Manuals supplied with the devices before handling the devices. Following connectors are prepared on the SC-921. Connect the connectors coming from the machine head to the corresponding places so as to fit the devices mounted on the machine head.
  • Page 7 ❷ 2) Loosen screw B in cover ❷ with a screwdriver to open the cover. ❶ 1) Pass cords ❶ of the thread trimming solenoid, reverse-stitching solenoid, etc. and the cord from the motor through hole A in the table to route them down under the machine table.
  • Page 8 [Connection of the reactor box fan cord] Connect the connector of reactor box fan cord  to connector  (CN62 : 6P) of SC-921. (Caution) Be sure to turn OFF the power before connecting the connector. 8) After inserting the connector, put all cords togeth- er with cable clip band  located on the side of the box.
  • Page 9 9) Close cover ❷ and fix the cover by tightening screw B with a screwdriver. (Caution) Take care not to allow the cord to be caught under cover ❷ . ❷ 10) Connect connector 4P  to connector  located on the side of the box.
  • Page 10 240 V to 100 - 120 V If it is connected between 1-3 or 2-3, the sewing machine will be inoperative. • Change the power cord with the JUKI genuine cord (Box side) (Plug side) with the part number (M90355800A0). Change...
  • Page 11 [In case of using the power switch for LA] Connect motor output cord  to connector  locat- ed on the side of the box. Installing power switch JA 3ø 220V Connect power supply cord to the power switch. Black [JA specifications] 200V-240V 3-phase 220 V :...
  • Page 12 4) Remove two screws to remove clamping plate from the main body of the control box. 5) Remove connector while holding its locking section with your fingers. 6) Turn connector to remove the cord locking section. 7) Loosen nut to remove the connector from clamping plate –...
  • Page 13 8) Put locknut on the power cord and draw out the cord from inside clamping plate 9) Install clamping plate back to the control box. 10) Pass power cord through conduit 11) Fix conduit with locknuts with clamping plate placed between the locknuts. 12) Close underside cover and secure the cover with screw...

  • Page 14: Attaching The Connecting Rod

    Make sure that the power switch is turned OFF and insert power supply cord coming from the power switch into the power plug socket. (Caution) 1. Top end of power supply cord varies in accordance with destination or supply voltage. Check again the sup- ply voltage and the voltage designat- ed on the control box when installing the switch.

  • Page 15: Setting Procedure Of The Machine Head

    (Caution) For the operation panel other than CP-18, refer to the Instruction Manual for the operation panel to be used for the setting procedure of the machine head. 1) Refer to “III-6. Setting of functions of , and call the function SC-921” p.23 setting No. 95. ❸ ❹ ❺...

  • Page 16: Adjusting The Machine Head (Direct-Drive Motor Type Sewing Machine Only)

    6. Adjusting the machine head (direct-drive motor type sewing machine only) (Caution) 1. When the slip between the marker dot on the handwheel and the concave of the cover is ex- cessive after thread trimming, adjust the angle of the machine head by the operation below. 2.

  • Page 17: For The Operator

    III. FOR THE OPERATOR 1. Operating procedure of the sewing machine 1) Press ON button ❶ of the power switch to turn ON the power. (Caution) If the power indication LED does not light up even when turning ON the power switch, immediately turn OFF the power switch and check the voltage.

  • Page 18: Operation Panel (Cp-18)

    2. Operation panel (CP-18) Ⓑ Ⓐ ❶ Ⓒ Ⓓ ❷ ❸ ❹ ❺ ❻ Ⓔ ❼ ❶ switch : Used for changing over effective/ineffective of the reverse feed stitching pattern. ❷ switch : Used for changing over effective/ineffective of the overlapped stitching pattern. ❸...

  • Page 19: Operating Procedure Of The Sewing Pattern

    3. Operating procedure of the sewing pattern (Caution) 1. For the operation panel other than CP-18, refer to the Instruction Manual for the operation panel to be used. 2. For some machine heads, reverse-stitching pattern cannot be used. (1) Reverse feed stitching pattern Reverse feed stitching at sewing start and reverse feed stitching at sewing end can be separately pro- grammed.

  • Page 20: Overlapped Stitching Pattern

    (2) Overlapped stitching pattern Overlapped stitching pattern can be programmed. A : Number of stitches of normal stitching setting 0 to 15 stitches B : Number of stitches of reverse stitching setting 0 to 15 stitches C : Number of stitches of normal stitching setting 0 to 15 stitches D : Number of times of repetition 0 to 9 times...

  • Page 21: One-Touch Setting

    A part of function setting items can be easily changed in the normal sewing state. (Caution) For the setting of functions other than those covered in this part, refer to “III-6. Setting of functions of SC-921” p.23 [One-touch setting procedure] Ⓐ...

  • Page 22: Production Support Function

    5. Production support function The production support function consists of three different functions (six different modes) such as the pro- duction volume management function, operation measuring function and bobbin counter function. Each of them has its own production support effect. Select the appropriate function (mode) as required. ■...
  • Page 23 Sewing can be performed with the production support data displayed on the control panel. [Basic operation of the production support modes] switch ❼ is pressed 1) When Ⓐ ❶ Ⓑ Ⓒ in the normal sewing state, LED Ⓔ lights up to enter the production sup- port mode.
  • Page 24 Table 2: Mode resetting operation switch ❺ (held pressed for 4 seconds) switch ❺ (held pressed for 2 seconds) Mode name Target No. of pcs. Resets the actual number of pieces display mode Resets the difference between target num- [F100] ber of pieces and actual number of pieces Target/actual No.

  • Page 25: Setting Of Functions Of Sc-921

    6. Setting of functions of SC-921 Functions can be selected and specified. (Caution) For the function setting procedure of any operation panel other than CP-18, refer to the In- struction Manual for the operation panel to be used. 1) Turn ON the power with Ⓐ...

  • Page 26: Function Setting List

    7. Function setting list Setting Ref. Item Description Indication of function setting range page Soft start The number of stitches to be sewn at a low speed when the soft- function start function is used at the start of sewing. 0 to 9 0 : The function is not selected.
  • Page 27 Setting Ref. Item Description Indication of function setting range page 29 Setting of one- This function sets the suction time of initial motion of back-tack touch type solenoid. 50 to 500 reverse feed 50 ms to 500 ms (ms) solenoid pull-in time 30 Function of Function of reverse feed stitching on the way...
  • Page 28 Setting Ref. Item Description Indication of function setting range page 53 Compensation Compensation of releasing the solenoid for reverse feed stitching of solenoid- when reverse feed stitching at the end of sewing is performed. off timing of –36 to 36 reverse feed (10°) stitching at the...
  • Page 29 Setting Ref. Item Description Indication of function setting range page 91 Function of It is effective in combination with the machine head provided with prohibiting tension release function. compensation 0 : Tension release function is ineffective. operation 1 : Tension release function is effective. after turning handwheel by hand...

  • Page 30: Detailed Explanation Of Selection Of Functions

    8. Detailed explanation of selection of functions ① Selection of the soft-start function (Function setting No. 1) The needle thread may fail to interlace with the bobbin thread at the start of sewing when the stitching pitch (stitch length) is small or a thick needle is used. To solve such problem, this function (called “soft-start”) is used to limit the sewing speed, thereby assuring successful formation of the starting stitches.
  • Page 31 ⑧ Selection of the optional input/output function (Function setting No. 12) Ⓐ Ⓑ ❶ ❸ ❹ ❺ ❻ ❷ ❼ Select function setting No. 12 with the operating procedure of function set- ting procedures 1) through 3). Select the items of "End", "in" and "ouT" with keys ❺ and ❻ . [When "in"...
  • Page 32 Input function list Function Abbrevia- Function item Remarks code tion No function (Standard setting) Needle up / down compensat- Every time the switch is pressed, normal feed stitching ing stitching by half stitch is performed. (Same operation as that of up / down compensating stitching switch on the panel.) Back compensating stitching Reverse feed stitching is performed at low speed while...
  • Page 33 Output function list Function code Abbreviation Function item Remarks No function (Standard setting) Thread trimming output Output of thread trimming signal Thread wiper output Output of thread wiper signal Thread release output Output of thread release signal Presser lifter output Output of presser lifting signal Reverse feed stitching output Output of reverse feed stitching signal...
  • Page 34 ⑨ Sewing counting function (Function setting No. 14) The function counts up every time thread trimming is completed and counts the number of completion of the sewing process. 0 : off Sewing counting function is inoperative. 1 : on Sewing counting function is operative. (Every time thread trimming is performed) 2 : on External sewing counter switch input.
  • Page 35 ⑬ Function of reverse feed stitching on the way (Function setting Nos. 30 to 33) Functions of the limit of number of stitches and thread trimming command can be added to the touch back switch on the sewing machine head. Function setting No.
  • Page 36 ⑮ Holding time of lifting presser foot (Function setting No. 47) This function automatically lowers the presser foot when the time set with the setting No. 47 has passed after lifting the presser foot. When the pneumatic type presser foot lifter is selected, the holding time control of lifting presser foot is limitless regardless of the set value.
  • Page 37 ⑰ Foot lift function after thread trimming (Function setting No. 55) This function can automatically lift the presser foot after thread trimming. This function is effective only when it is used in combination with the AK device. 0 : off Function of automatically lifting the presser foot is not provided.
  • Page 38  Function of soft-down of presser foot (with AK device only) (Function setting Nos. 70 and 49) This function can softly lower the presser foot. This function can be used when it is necessary to decrease contact noise, cloth defect, or slippage of cloth at the time of lowering the presser foot.
  • Page 39  Initial motion UP stop position move function (Function setting No. 90) Effective/ineffective of automatic return to UP stop position immediately after turning ON the power can be set. 0 : Ineffective 1 : Effective  Function added to the needle up / down compensating switch (Function setting No. 93) One stitch operation can be performed only when the needle up / down compensating switch is pressed at the time of upper stop immediately after turning ON the power switch or upper stop immediately after thread trimming.

  • Page 40: Automatic Compensation Of Neutral Point Of The Pedal Sensor

    9. Automatic compensation of neutral point of the pedal sensor Whenever the pedal sensor, spring, etc. are replaced, be sure to perform following operation : Ⓐ switch ❹ , turn ON the Ⓑ 1) Pressing ❶ power switch. 2) Compensated value is displayed on indicator Ⓑ...

  • Page 41: Setting Of The Auto Lifter Function

    11. Setting of the auto lifter function WARNING : When the solenoid is used with the air drive setting, the solenoid may be burned out. So, do not mistake the setting. When the auto-lifter device (AK) is attached, this function makes the function of auto-lifter work. 1) Turn ON the power switch with Ⓐ...

  • Page 42: Selecting Procedure Of The Key-Lock Function

    13. Connection of the pedal of standing-work machine 1) Connect the connector of PK70 to connector ❶ (CN39 : 12P) of SC-921 . 2) Tighten the cord of PK70 together with other cords with cable clip band ❷ attached to the side of the box after passing it through the cable clamp.

  • Page 43: External Input / Output Connector

    Rotation by pedal is prohibited while “L” signal is being DC5V, –5mA inputted. SOFT Input Rotation speed is limited to the soft-speed while “L” DC5V, –5mA signal is being inputted. SGND JUKI genuine part No. Connector : Part No. HK016510130 Pin contact : Part No. HK016540000 – 41 –...

  • Page 44: Connection Of The Material End Sensor

    15. Connection of the material end sensor 1) Connect the connector of material end sensor to connector ❶ (CN54 : 4P) of SC-921. 2) Tighten the cord of the material end sensor together with other cords with cable clip band ❷...

  • Page 45: Initialization Of The Setting Data

    16. Initialization of the setting data All contents of function setting of SC-921 can be returned to the standard set values. 1) Turn ON the POWER switch with all Ⓐ Ⓑ ❶ switch ❹ , switch ❺ and switch ❻ held pressed.

  • Page 46: Replacing The Fuse

    3) Loosen setscrew ❷ in cover ❶ . Open cover ❶ . ❷ ❶ 4) To close cover ❶ , re-tighten setscrew ❷ while paying attention to the orientation of cable clip band ❸ mounted on the side face of the box. ❸...

  • Page 47: Ctl Pcb

    (2) CTL PCB 1) Open the cover of the control box. 2) Pick up the glass section of fuse ❸ mounted on the CTL PCB with fingers ❸ to remove it. (Caution) In order to protect against the possibility of electric shock, it is necessary to remove the fuse after LED ❷...
  • Page 48 In addition, there are the following error codes in this device. These error codes interlock (or limit function) and inform the problem so that the problem is not enlarged when any problem is discovered. When you re- quest our service, please confirm the error codes. [Checking procedure of the error code] Ⓐ...
  • Page 49 Description of error Cause of occurrence expected Items to be checked detected E053(*) Notification of produc- • This error number is displayed after tion support function the execution of initialization of the initialization (This is production support function or up- not an error) grading of the program.
  • Page 50 • When voltage higher than guaran- • Check whether the applied power voltage is teed one is inputted. higher than the rated voltage + (plus) 10% or • 200V has been inputted to SC-921 more. of 100V specifications. • Check whether 100V/200V changeover con- •...

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