Data Sheet. Stepper Motor Drive Boards. Features

Transcription

1 Data Pack B Issued March 0-6 Data Sheet Stepper Motor Drive Boards Unipolar stepper motor drive board (RS stock no. 7-6) and bipolar stepper motor drive board (RS stock no. -906) The unipolar drive board is capable of driving any -phase stepper motor up to A, dc/phase (including the RS 7. motors with much improved stepping rates over the driver ic. The bipolar board is capable of driving any -phase stepper motor up to.a, 6V/phase, the board may be used as a stand alone unit or in conjunction with external logic. Features Directly compatible with any of the RS stepper motors Eurocard system compatible. Alternatively they may be surface mounted Full step and half step drive s External control inputs are CMOS and open collector TTL logic compatible On-board power supplies for external circuit energisation Provision for assembling on-board oscillator (if external clock is not available), having clock pulse output, base speed, running speed and stop/run controls. Technical specification Unipolar stepper motor drive board Bipolar stepper motor drive board Size Eurocard 68 0 Eurocard 0 6 Mating edge connector Standard way DIN 6 socket High power way DIN 6 socket eg. RS stock nos. 7-0 or 67- eg. RS stock nos. 7-9 or 7- Supply - board -dc + % max. unregulated -Vdc + % max. unregulated smoothed - motor smoothed -6Vdc + % max. unregulated smoothed Current consumption - 0mA max. - board only ma typ. 80mA typ. - motor windings Dependent on motor used - up to Dependent on motor used - up to A/phase max../phase max. On-board auxiliary output Vdc 0mA max. regulated Vdc 0mA max. regulated Vdc 0mA max. regulated Switching logic control inputs Level '0' Level '' V } CMOS and open collector TTL compatible a) Full/ Level '' full step, level '0' half step b) Direction Clockwise or anticlockwise c) Clock step Hz-kHz, µs minimum pulse with negative edge triggered d) Preset Active level '0'. Sets motor drive to Q and Q OFF, Q and Q ON (full step ), Q, Q and Q OFF, Q ON (half step ) Operating temperature range 0 C to +0 C 0 C to +0 C }

2 -6 Figure Unipolar stepper motor drive board connections External controls Full/half step Clock Direction Preset RS stock no. 7-6 All board connections are to the a side of the DIN connector On-board Oscillator control inputs oscillator (when assembled) *R = +V motor - rated winding voltage (see oscillator section) rated winding current Auxiliary output Vdc 0mA Board supply ( - dc) +V Board and motor may share the same supply +V motor (dc max.) R* R* Ø Ø Ø Ø Motor windings Ø - Ø Figure Bipolar stepper motor drive board connections c 6 8 BOARD a Ø Ø Ø Ø Motor Supply (+V to +) Ø Lead motor Ø Ø Ø N/C Synch I/O Home Ø output Step clock input (Link to C if onboard VCO fitted) Overload output Overtemp output (optional ) VCO clock output VCO clock output Aux V output (0mA max) Logic supply (+V to +V) Common This facility requires the fitting of a thermal switch Logic may share motor supply if between +V and +V If the on board VCO has been fitted the VCO output may be connected directly to the step clock output Run Stop Stop Run no ramping N/C Base speed (optional) +V High speed values kω to kω 6 Lead motor Ø Ø Ø Ø Base High kω to Optional kω Base Base high speed ramps values between kω to base and high speeds or zero and high speeds if no base speed pot is fitted These components are only required if on-board VCO has been fitted Current Output program disable normally uses onboard DIP switch Reset Ø state Half CW Full 8 Lead motor (Parallel connections) CCW Maximum power dissipated through R = (rated motor current) R. If the power dissipation is high it is advisable to arrive at the required value of R by using a network of series or parallel resistors. The use of heat sinks and higher wattage resistors may be necessary in applications where power dissipation is excessive. Maximum current consumption (motor + board) = (current per phase) + ma for unipolar board, 0mA for bipolar board. Thus ensure power supply cables used are sufficiently rated. External control signal eg. full/half step, direction etc as well as the oscillator (if fitted) stop/run signal can be applied to the board in any of the methods of Figure. Figure External control input applications (a) Open collector T.T.L. (b) C.M.O.S. + V) (c) Opto-coupler (d) Simple switch

3 -6 Connection to RS unipolar stepper motor board When the windings of the RS stepper motors are assigned (0-0) as shown in Figure, they can be connected to the board according to Figures or. Figure Motor winding connections If the supply voltage is set to Vdc then R values for use with the RS motors are given in Table. Table /White Green White Ø Ø Ø Ø Green/White.8 Stepper Motor RS stock no. 0- Ø Ø Ø Ø Orange Yellow White/ White/ / Yellow/ OrangeWhite White.8 Stepper Motor RS stock no. 0-6 Ø Ø Ø Ø 7. Stepper Motor RS stock no. -97 RS stock no. -9 Motor Rated current Rated winding R Power dissipation RS stock no. (A) voltage (V) (Ω) through R (W) Here the 7. motors are driven in the L/R while the.8 motors are driven in the L/R and L/8R s respectively. Characteristics of unipolar drive board Typical pull-out performance characteristics (under no-load conditions) for the RS motors when being driven by the drive board RS stock no. 7-6 using a Vdc supply and series resistance as in Table are given in Figures to 8.** ** These results are typical at C. If the motor temperature rises due to power dissipation in the windings and/or higher ambient temperatures the torque capability decreases (typical torque derate - 0.% per degree rise in temperature). Figure 6 Pull-out performance for 7. size stepper motor (with RS drive board RS stock no. 7-6) resonance region 0 resonance region full step 0 0 half step 00 0 full step half step Full step 00 full steps/s 00 half steps/s Figure 7 Pull-out performance for.8 stepper motor type (with RS drive board RS stock no. 7-6) 00 full steps/s 000 half steps/s Figure 8 Pull-out performance for.8 stepper motor type (with RS drive board RS stock no. 7-6) 000 full steps 000 half steps Figure Pull-out performance for 7. size stepper motor (with RS drive board RS stock no. 7-6) 7 6 resonance region full step full steps/s 00 half steps/s

4 -6 Connection to RS bipolar stepper motor board When the windings of the RS stepper motors are assigned (Ø-Ø) as shown in Figure 9, they can be connected to the board according to Figure. Figure 9 Motor winding connections /White Green Green/White Orange White Ø Ø Ø Ø.8 Stepper Motor RS stock no. 0- The flexibility of on-board motor current selection enables a wide range of motors to be utilised. The best high speed torque performance will be obtained by using a motor with a higher current rating than the drive card (typically.a to 6A) and a low winding inductance although low speed torque may suffer. Conversely for high torque low speed operation a motor with a higher winding resistance and inductance should be used. When using 8 lead motors with coils in parallel the motor current should be set to greater than: I per phase When using 6 lead or 8 lead motors with coils in series the motor current should be set no greater than: I per phase Motors with leads have a bipolar rating and can be used according to manufacturer's specification. White/ White/ / Yellow/ Orange White White Ø Ø Ø Ø Yellow.8 Stepper Motor RS stock no. 0-6 Ø Ø Ø Ø 7. Stepper Motor RS stock no. -97 RS stock no. -9 Nominal motor current vs. switch settings Nominal current Switch settings per phase S S S S.A ON ON ON ON.A OFF ON ON ON.0A ON ON ON OFF.7A OFF ON ON OFF.A (RS stock no. 0-6) ON ON OFF OFF.A OFF OFF ON ON A ON OFF ON OFF.6A OFF OFF ON OFF.A ON OFF OFF OFF 0.7A (RS stock no. 0-) OFF OFF OFF OFF An external current setting resistor may also be added between pin 8C and to reduce the motor current if required. This facility is particularly useful for interchangeability in multi axis systems using different motors, as all drive boards can be set at maximum and an external resistor added to dedicate that particular axis. Another useful application for this feature is to switch in a resistor at standstill to produce a holding torque (typically %) and conserve power. To select the required current connect a high impedance voltmeter from pin 8C to and increase/decrease the external resistor until the correct voltage is achieved, where the nominal scaling factor is V = I per phase 0.7 Installation - general notes. SERIOUS DAMAGE WILL OCCUR if a motor lead becomes disconnected whilst the drive is energised.. The drive board should always be mounted such that the heatsink fins are vertical ie. board on edge, and adequate clearance be given top and bottom ie. mm minimum. When rack mounting the board there should be at least a mm clearance between the heatsink and an adjacent board.. When using the drive at high ambient temperatures or at slow speeds/standstill at maximum current and voltage it will prove advantageous to force cool the heatsink.. Motor and power supply connections should be made in at least /0.mm wire due to the high peak currents flowing, all other wiring can be 7/0.mm.. No damage will occur, but the Full step/ input (pin 6a) should be connected as required before the drive is energised.

5 -6 Characteristics of bipolar drive board Figure Pull-out performance for.8 stepper motor type (with RS drive board, RS stock no. -906) Ncm On-board oscillator assembly If an external clock source is not available an on-board oscillator can be assembled simply by soldering into place the required components listed below - see current RS Catalogue. Note: That the oscillator clock output must be externally wired to the clock input - pin c. To pin c Running speed control Clock output. Starting (base) speed control Stop/run (V)/() PLI +V PLI R k Full step R 0k TPI C R k R k +V D IC6 7 CD06 8 R6 R (R) 0kΩ resistor RS stock no. -9 off R,, (R, 6, 7) kω resistor RS stock no. -78 off D6, 7,8,9 (D,,, 6) Signal diode RS stock no. 7-6 off IC6 CMOS IC RS stock no off R6 (R), C & C (Value depends on application) off each Circuit references in brackets refer to bipolar board. 09 +V D6 D Speed 000 Hz Figure Pull-out performance for.8 stepper motor type (with RS drive board, RS stock no. -906) Ncm Full step Speed 000 Hz Figure On-board oscillator Refer to instruction sheet packed with product for full details +V C If oscillator remote controls are required (eg. front panel controls) then plug PL (-way inter-pcb RS stock no ) can be added together with mating cable shell RS stock no and crimp terminals. Starting (base) and running speed control The on-board oscillator can be arranged to start at a fixed frequency (thus a fixed motor speed) and then ramp up to a final value (the running motor speed). This facility is available to start the motor within its pull-in performance region and then accelerate the motor to its final speed such that it can operate within the pull-out. On switch-off the motor decelerates automatically. Three parameters need to be determined for any application:. The starting speed; this should be below pull-in speed for the motor (including any additional load).. The running (final) speed; this should be within the pullout capability of the motor (including any additional load).. The acceleration and deceleration rate between starting and running speeds; this is limited by the motor capability to accelerate through its own, plus any load, inertia. Running speed control Base speed control Note: Oscillator frequency corresponds directly to motor speed in steps/s or half step/s depending on the motor drive. For a.8 stepper motor speed in revs/min = x speed in step/s 0 or Figure External oscillator controls stop/run Base speed Switch ON PL SW ON V Ramp-up Decay Base speed 00 SW OFF ON Running speed k R x C time constant (typically 0ms) SW ON Use multi-turn potentiometers VR max. min. Figure Motor speed ramping characteristics M Switch-OFF x speed in half step/s max. min. VR Refer to instruction sheet packed with product for full details run stop

6 -6 Oscillator frequency setting Recommended component values (refer to Figures 8 and 9) VR 0 - mω use multiturn VR kω potentiometers R6 (R) kω - MΩ C greater than 0pF Determine the base frequency and maximum running frequency. Using Figure choose a value for C and VR. Calculate the ratio maximum running frequency/ base frequency to determine the ratio of VR + R (fixed at kω) R6 and thus using Figure 6 establish the required value for R6 (R). Figure Base frequency variations with timing capacitor C Base frequency (R6 = VR = min.) 6 VR = 0k VR = 0 Figure 7 Oscillator frequency range Max. running frequency Min. Base frequency VR setting Max. Once all component values are established and assembled the oscillator frequency range is as shown in Figure 7. If SW if OFF the oscillator runs at base frequency. When SW is ON the oscillator builds up at a rate (at a rate depending on R x C time constant) to a frequency determined by VR setting. VR = M C(µ F) Figure 6 Resistor value as a function of maximum frequency/base frequency VR + kω R6 RS Components shall not be liable for any liability or loss of any nature (howsoever caused and whether or not due to RS Components negligence) which may result from the use of any information provided in RS technical literature. RS Components, PO Box 99, Corby, Northants, NN7 9RS Telephone: 06 An Electrocomponents Company RS Components 998