While I'm waiting for funds to accumulate I continue to toy with idea of building DIY servo based system for Sherline mill from out of the box components. We had good discussion with Kirk offline, now I want to ask some questions in the list and present overall design for public discussion. Hopefully it could be useful for other too.
I'll put questions in front, so they are easy to spot and below will be assumptions and components listed. ------- Questions: - is there an inexpensive servo driver, which does not have closed loop inside (like Gecko do) ? - would K-CMD driver with max 24VDC capacity will be enough to drive 30VDC servo motors ? - would 36VDC power supply work fine with chosen servo motors and K-CMD motor drivers or 30VDC should be used instead ? - what other BB could be used in place of C1 and C11 ? - would built-in speed control of C11 work with Sherline DC spindle motor ? - would anybody be willing to check if chosen so far components would actually work together ? ------- Assumptions: (please correct me if I'm wrong) - signals from encoders will go via BOB through parallel ports back to EMC2. EMC2 is used as motion controller with closed loop - 3 axis kit is compiled to be built with minimum or no DIY production required. However 4th axis is included in design and will be added later - manual controls are required on servo belt reducers or shafts, so machine could still be used for some manual projects - spindle speed control planned, but might be not implemented at the beginning - no extra relays used for now, but possibility of wiring them should be in place - home switches planned for all three axises. Limit switched would require more BB and parallel ports to be used ------- Components: - servo motors with encoders and belt reducers from IMService - 3 x $140 = $420 http://www.cadcamcadcam.com/index.asp?PageAction=VIEWPROD&ProdID=61 http://www.cadcamcadcam.com/index.asp?PageAction=VIEWPROD&ProdID=62 - C1 or C11 BOB from CNC4PC.com - 2 x $70.12/$124 http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=47 There are other alternatives including C10 without opto-isolation or boards from other vendors. - double PCI parallel port card - $16 http://www.newegg.com/Product/Product.aspx?Item=N82E16815166007 Or similar card - KL-320-36 36V/8.8A Power Supply from Keling Inc - $59.95 http://www.kelinginc.net/SwitchingPowerSupply.html Is this unit powerful enough for chosen servos ? Depending on the servo drivers additional Power Supply could be needed. Again there are alternatives. Ex. - http://cgi.ebay.com/30V-10A-300W-Power-Supply-Stepper-motor-controller_W0QQitemZ270089686014 - 5V Power supply for BOB - $?? - motor and encoder cables - 3 x $?? + 3 x $?? (? $8 x 6 = $48 ?) Probably cables from IMService would be a good choice. - Servo motor drivers - 3 x $19 http://www.solarbotics.com/products/k_cmd/ Don't see any other simple/cheap servo driver, which can be used out of the box. However K-CMD might not be ideal for chosen servo motors. ------- Pins assignment for parallel ports 2 parports one configured as output and another as input should give 16 output and 19 input pins Port 0 Pin Signal Parallel Port Direction 1 X Amp PWM Out 2 X Amp Dir Out 3 X Amp Enable Out 4 Y Amp PWM Out 5 Y Amp Dir Out 6 Y Amp Enable Out 7 Z Amp PWM Out 8 Z Amp Dir Out 9 Z Amp Enable Out 10 X Home In 11 Y Home In 12 Z Home In 13 In 15 In 14 A Amp PWM Out 16 A Amp Dir Out 17 A Amp Enable Out Port 1 Pin Signal Parallel Port Direction 1 X Encoder A In 2 X Encoder B In 3 X Encoder Z In 4 Y Encoder A In 5 Y Encoder B In 6 Y Encoder Z In 7 Z Encoder A In 8 Z Encoder B In 9 Z Encoder Z In 10 A Encoder A In 11 A Encoder B In 12 A Encoder Z In 13 In 15 E-Stop In 14 Spindle PWM Out 16 Spindle Fwd Out 17 Spindle Rev Out ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
