27938 Parallax

LK Little Step-U Unipolar Stepper motor controller Description The Little Step-U is a complete, serially CON 1 controlled, drive system for unipolar stepper /IP1 /IP2 motors. Using an intelligent module allows the BUSY SERIAL OUT host system to concentrate on the task at hand SERIAL IN while the Little Step-U performs all calculations Vcc (+) GND (-) and operation of the motor. CON 2 COIL A The desired operating speed, ramp time and COIL B COIL C drive mode can be configured once and then a COIL D CT - AC single command used as required, to move to CT - BD CON 3 fixed or relative positions. While the motor is in Vom (-) motion, a BUSY output is active and the Vm (+) movement can be optionally interrupted by one of the two external inputs. The position of the 1.0 in motor is maintained in a readable register which can be set to zero (Home) by a command or when an input is activated. A similar register is available to save a second position (Mark) either Features by command or from an input. These points can then be referenced directly with a Move to Unipolar motors to 35V, 3.0A home or Move to mark command. Full step, half step and wave drive modes 1-5,000 steps per second A built-in ramping function accelerates the Inbuilt speed ramp (0.1-20.0 seconds) motor from a standstill to the desired speed over Simple serial commands (TTL interface) a specified time period, allowing faster final Separate power input for motor and logic speeds to be achieved, and also to decelerate Suitable for direct and L/R operation in all the motor to give maximum load braking. When modes the motor is stopped, a command specifies On board clamping diodes whether the windings are left energized (for Current position register (+/-100,000,000) maximum holding torque) or turned off (for lower Zero position and user marker registers power consumption / dissipation). Absolute & Relative movement commands Busy output A remote function is included for use in more Two inputs suitable for optical stops complex systems. Once activated, the two Slave mode using inputs for STEP & DIR external inputs become STEP and DIR, with the Stop with motor coils on or off motor stepping in the indicated direction with every pulse applied to the step input. CT-AC LK CT-BD Vcc A B C D GND Vom TLA Microsystems Ltd DC Characteristics Characteristic Symbol Min Typ Max Unit Notes Logic Supply Voltage V 4.5 5.0 5.5 V CC Vcc risetime t 0.05 V/ms 1 VCC Logic supply current I 1.5 3.0 mA CC Input Low Voltage V 0.0 1.0 V IL Input High Voltage V 4.3 Vcc V IH Output Low Voltage V 0.6 V OL Output High Voltage V 4.3 V OH IP1/2 Source Current I 1.0 mA OL Motor Voltage V 50 V M Motor current I 3.0 A M Motor resistance R 2.8 M Clamp diode current I 250 mA CL Step rate F 1 5000 steps/sec STEP Speed Error F +/- 0.5 % 2 ERR Comms bit rate F 2400 bps BIT BUSY rise/fall time T 10 25 ns RF Response time to IP1/2 T 1 ms 3 INP DIR hold time T 8 us DIR Max Slave step rate F 10000 steps/sec 4 EXT Operating temp t 0 70 C 5 OP Storage temp t -40 100 C ST 1 Required to ensure reliable startup. 2 As a percentage of requested speed 3 Response to IP is lesser of 1ms or 1 step 4 If no comms while stepping. Max = 6000 steps/sec with comms 5 Refer loading derating graph Pin functions Connector 1 Pin Function /IP1 Optional input 1. Set home. Emergency stop. /IP2 Optional input 2. Set mark. Emergency stop. BUSY Output - High when motor moving SERIAL OUT Data from Little step-U to controller. TTL SERIAL IN Data from controller to Little Step-U. TTL Vcc Supply to logic circuits GND Supply ground. Common with motor circuits. Connector 2 Pin Function A Winding A output B Winding B output C Winding C output D Winding D output CT-AC Common for windings A & C CT-BD Common for windings B & D Connector 3 Pin Function V Motor supply ground. Common with logic circuits OM V Motor Supply + M 2 Little Step-U