stepperboard BiStep Universal Bipolar and Unipolar Stepper Motor Controller

Raw board and assembled versions of BiStep revision A05 kit

This product has been discontinued, and is only available for special order as a volume purchase. Please contact the factory if you have a requirement to use this board. The recommended replacement for this board is the BiStepA06.

The BiStep version A05 board is a complete Unipolar/Bipolar dual stepper motor controller system. It includes the capability of driving one or two stepper motors, each of which being either unipolar (4-pole) or bipolar (2 pole). This unit is a good choice for those designing products using linear actuators, especially since the microstepping features will reduce noise levels and can increase positional accuracy by a large amount.

The board is specified as allowing up to 0.6 amps per motor winding, with 7.5 to 15 volt motors supported when in single power supply mode. It also supports a dual power supply feature, wherein the motors use a separate supply from the logic circuits; in this mode, up to a 35 volt power supply may be used for the motors. You will want to review the calculating motor current faq in order to determine the current requirements for your motor. Please note that Parallax, Inc. currently stocks an upgraded special-edition version of this product (the BiStepA05-1A) which operates at 1.0 amps per winding. Please click here to go to their product page describing the offering.

Double Current Mode: The GenStepper firmware (version 1.59 or later) for our products now allows you to run one motor (instead of two) at double the rated current of the board! For example, if you purchase a BiStepA05 board, which can handle two 0.6-Amp motors, then that board can now be configured by you to handle one 1.2-amp motor instead. Please review the motor connections faq for more information.

This board may be optionally configured to act as a serial router for our product line, through use of the SerRoute firmware option. This option replaces the stepper motor control with serial routing of up to five boards, 8 relay, and up to 4 TTL input operations. Please click here for more information about the serial routing firmware.

Similarly, this board may be optionally configured to operate in a NC (numerically controlled) process environment, through use of the NCStepper firmware option. This firmware tightly links the two motors together, providing for easy "exact straight line" and simplified arc/circle drawing. Please click here for more information about the NCStepper firmware.

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Key Benefits

The BiStep version A05 has the following key capabilities when using the GenStepper firmware:

	Up to two stepper motors may be independently controlled at one time.
	Each motor may be either 4-pole Unipolar or 2-pole Bipolar.

Each motor may draw up to 0.6 amps per winding. Note if more than 0.5 amp motors are used, then the board requires external fan-based cooling (10 CFM is a reasonable amount); otherwise the board can overheat and fail if the motors are left enabled for long periods of time.

If only a single motor is connected to the board, and the GenStepper firmware revision is 1.59 or later, then you can configure the board and wire the motor for double current mode. This allows you to handle a single motor with up to 1.2 amps/winding. Again, use of a cooling fan is usually required when operating in double current mode.

The connectors to the motors are explicitly designed to be reversible; this means that to reverse the default direction of an attached motor, merely remove the connector and turn it around.

Limit switches may be used to automatically request motion stop of either motor in either direction.

Rates of 1 to 62,500 microsteps per second are supported.

Step rates are changed by linearly ramping the rates; the rate of change is independently programmed for each motor, and can be from 1 to 62,500 microsteps per second per second.

All motor coordinates and rates are expressed in programmable microstep units of 1/2 to 1/64 of a full step. Once the base step size is selected, changing stepping modes between half, full and micro does not change any other value other than which winding pairs may be driven at the same time.

Motor coordinates are maintained as 32 bit signed values, and thus have a range of –2,147,483,647 through +2,147,483,647.

Both GoTo and Slew actions are fully supported.

Four modes of stepping the motor are supported:

	Half steps (alternates 1 winding and two windings enabled at a time),
	Full power full steps (2 windings enabled at a time)
	Half power full steps (1 winding enabled at a time)
	Near-constant-current microsteps (each from 1/64 to 1/2 of a full step)

A TTL "busy" signal is available, which can be used to see if the motors are still moving. Note that this information is also available from the serial communications subsystem.

Simple control of the motors may be done by switch closure: i.e., each motor can be told to slew left or right, or to stop by simply grounding some input lines. Similarly, the rate of motion can be controlled via stepping through a standard set of rates via grounding another input.

Complete control of the motors, including total monitoring of current conditions, is available through the 2400 or 9600 baud serial connection.

An additional mode is available which allows an external computer to directly generate step sequences on the motor control lines. Up to 62,500 microsteps per second may be requested.

The system can be configured to operate in 1/2 power mode, wherein it reduces the power to all windings by 1/2 for all actions. This can be used to "overvoltage" a motor, in order to generate more torque.

Runs off of a single user-provided 7.5 to 15 volt DC power supply. May also be configured using a split supply, wherein the motor runs off of a 7 to 35 volt DC power supply, while the logic circuit runs off of a 7.5 to 15 volt supply.

Theoretically, an unlimited number of boards can be controlled via one serial line, if the SerRoute product is used.

Click Here for the full PDF manual for the UniversalStepper Product Line.

Click here if you need to download the current version Adobe Acrobat Reader from Adobe's site.

We accept American Express, MasterCard, Visa and Discover for orders from the USA. For international orders, we require wire transfers.

All products come with a 30 day satisfaction guarantee, and the assembled products come with a 30 day return to factory warranty. Please click here for the details...

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Key Benefits

Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008 Peter Norberg Consulting, Inc.