Stand Alone Stepper Motors

For particularly smooth and precise motor operation, JVL''s very compact Ministep Drivers are recommended. Model SMD41 operates with 20-80VDC supply voltage while model SMD42 operates with 20-160VDC supply voltage for highly dynamic applications.

The drivers are available in 2 basic models, each of which is available in 3A, 6A, and 9A versions. One of the Drivers provides step resolutions of Full, Half, 1/4 and 1/8 ministeps/step, the other a selection of 10, 25, 50 or 125 ministeps/step thus providing resolutions of up to 25,000 steps/revolution.

For optimum performance with different motor types, 4 selectable current profiles are built in. The Drivers provide automatic switching between operating and standby currents, optically isolated inputs for step-pulse and direction signals, and control inputs for operating/standby current.

There is an error output for temperature and short-circuit conditions and a special Power Dump output for overload protection. As standard, the Ministep Drivers are constructed for mounting on a heat sink or a machine in proximity to the motor, thus avoiding long motor cabling. The Drivers can also be supplied mounted on a heat sink or for mounting in Eurocard racks. 

Step Motor Driver SMD73 is a miniature driver that measures only 52.4x52.4 mm and is ideal for direct mounting onto a step motor. It fits onto most types of high-torque motors, but of course can also be mounted on a surface.

The Driver can supply 2.6A RMS in each phase, and current is automatically regulated to 0.8A when the motor is not receiving step pulses. The Driver controls the motor in half-step mode, which results in 400 steps/rev. SMD73 can handle up to 50 ksteps/sec and a "half-step" current regulation ensures that the current is increased by a factor of 1.4 every second step on each phase, in order to yield maximum motor torque.

The Driver can be powered from an 18 - 28VDC supply. It is equipped with 2 indicators: a green LED indicates that power is on and a red LED indicates an error condition.

For other applications, the Driver is available with step resolutions of  1/1, 1/2, 1/4, 1/5, 1/8 steps/rev and with selectable motor current.

The Driver is equipped with an 8-pole connector. 4 terminals are used to connect the motor, 2 are used for the external power supply, and the remaining 2 are used to control the motor via step-pulse and direction signals.

As standard, SMD73 has half step and 2.6A RMS phase current. If required, the Driver can be supplied with step resolutions of 1/1, 1/2, 1/4, 1/8 step/rev., and specified motor current. Also available for controlling DC motors.

Step Motor Driver PA0073 can also be configured by JVL to control DC- or step motors at selectable velocity, stand-by/operating current, change of direction, etc. For example, it is possible to control a DC motor so that input 1 selects start/stop and input 2 determines velocity.

All JVL Drivers operate using the Bipolar Chopper principle and have a 2-phase motor output. The Drivers are used both with 2-phase and 4-phase motors, the latter being connected with the phases in parallel so they appear as a 2-phase motor to the Driver.

This facilitates simple driver construction. In Full-Step operation, step motors typically provide a resolution of 200 steps per revolution, i.e. each step is 1.8 degrees (360 degrees/ revolution). By operating the motor in Half-Step mode, 400 steps/revolution can be achieved (0.9 degrees/step). All JVL Drivers can be operated in Half-Step mode.

Even greater resolution can be achieved by further subdivision into 1/4, 1/8 steps etc. Some JVL drivers can also be operated in 1/4 and 1/8 step-mode. Similar results can be achieved using motors with an increased number of phases but this makes the Driver unnecessarily complicated and more expensive compared with the purely electronic solution to smoother and more precise motor control the Ministep Driver.