BC2DNCStepper Firmware

Available only as a direct factory-order option, the BC2D15NCStepper firmware is designed to allow the BC2D15 controller to operate dual-axis stepper motor systems, wherein the intent is to control the pair of motors as one unit. It supports "perfect line" drawing, wherein the firmware controls the relative X,Y stepping rates needed to cause straight (linear) motion between specified pairs of X,Y addresses. Additionally, the code provides a simplified arc/circle (actually, a polygon) drawing tool, which permits easy drawing of near-circles and similar figures.

In order to perform the linked-motor operations, the firmware makes the assumption that one "step" on the X motor generates the same distance of motion as one "step" on the Y motor. It also assumes that the gear system has no "windup" required when the direction of rotation is changed. That is to say, location 1245 is physically the same when approached from location 2047 as it is from 999 (zero backlash).

The BC2D15NCStepper firmware shares many of the features of the BC2D15PotStepper dual-motor controller firmware. The current control of the motors is identical, as is the general method of sending numeric parameters for commands. Many of the commands which configure the system are also identical (such as setting the step rate); however, the fundamental control theory is different. The BC2D15NCStepper firmware explicitly controls both motors at the same time, from a single command (such as Goto or Arc), with automatic step-rate ratioing in order to generate straight lines; while BC2D15PotStepper explicitly controls the two motors independently, so that one motor may be performing a "slew" operation, while the other is executing a "goto".

The current version (using Adobe format) of the UCNCStepper manual for all of our products is available by clicking here. Hint: If you want to save your own copy of the manual, right click on the above link, and then select the 'Save Target As...' option which appears. Tell the system where to save the manual, and then you will be able to browse it at your leisure.

Short Feature Summary

	Two bipolar stepper motors are to be controlled at one time.
	Each motor's current may be separately specified.
	Limit switches may be used to automatically request stop of motion if either motor reaches a limit in either direction.
	Rates of 1 to 44,801 microsteps per second are supported.
	Step rates are changed by linearly ramping the rates. The rate of change can be from 1 to 44,801 microsteps per second per second.
	All motor coordinates and rates are always expressed in programmable microunits of up to 1/16^th step. Changing stepping modes between half, full and micro-steps does not change any other value other than which winding pairs may be driven at the same time, and how the windings are updated.
	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 Arc (actually, multi-line-segment) actions are fully supported.
	Arc vertex locations are calculated to a precision of about 1:10,000,000
	A TTL "busy" signal is available, which can be used to see if the motors are still moving. This information is also available from the serial connection.
	Complete control of the motors, including total monitoring of current conditions, is available through the 2400 or 9600 baud serial connection.
	Any number of motors may be run off of one serial line, when used in conjunction with one or more SerRoute controllers.
	A firmware option is available which allows user control of two of the TTL output lines on the BC2D15 board. This allows you to generate a pair of TTL signals, which can be used to control some external device.

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