RelayStepper Firmware

On March 3, 2004, we released a major upgrade to our RelayStepper firmware. This new release (version 2.2) allows for the optional use of a user-provided potentiometer to control the stepping rate of the stepper motor, and it permits 'connection' of two of the TTL input signals to the relay drivers. This provides for much more comprehensive control over the motor and the relays when a computer is not connected, and it allows 'manual' adjustment to the behaviors of the system even while the computer control (via the serial port) is operating.

Available as a direct factory-order option, the RelayStepper firmware is designed to allow our controllers to operate one stepper motor while driving up to 4 relays. Its operation of the stepper motor is almost identical to the control provided with the PotStepper firmware, and its operation of the relays is nearly the same as that available when using the SerRoute firmware.

The following table summarizes the currently released stepper motor control product key capabilities when operated using the RelayStepper firmware.

Product	Unipolar	Bipolar	Motor Winding Current	*Relay Drive Current*	*Motor* and Relay Voltages
SimStep	x		0.5 Amp	0.1 Amp	5-26
SS0705	x		0.5 Amp	0.1 Amp	5-26
BiStepA04	x	x	0.6 Amp	0.3 Amp	7.5-15
BiStepA06	x	x	1.0 Amp	0.5 Amp	5-34
BiStep2A	x	x	2.0 Amp	1.0 Amp	5-43

The RelayStepper firmware shares nearly all of the features of the PotStepper dual-motor controller firmware. The PWM control of the motors is identical, as are all of the motor control commands. The only motor-control related feature of PotStepper which is not present in RelayStepper is:

PotStepper has a "Double Power" mode, allowing it to operate one motor at double the rated current for the board.

The RelayStepper firmware shares the relay control capabilities of the SerRoute firmware, as well as SerRoute's simplified pulse-counting input and TTL input tools. The actual command letters are different, but the behavior is the same.

The current version (using Adobe format) of the common RelayStepper 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

All of the current stepper motor control products from Peter Norberg Consulting, Inc. share the same firmware and TTL control structures. Their common capabilities when used with the GenStepper firmware include:

One stepper motor and up to 4 relays may be independently controlled at one time.

If the pulse count command is used, up to 62,500 pulses per second (125,000 edges per second) may be detected on one of the TTL input lines.

The firmware allows configuration of the 9 inputs as TTL inputs, motor motion control, rate control, and relay control

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

The firmware maybe configured such that simple control of the motor may be done by switch closure: i.e., the 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 connecting a user-provided potentiometer to one of the inputs (this is in addition to the rate control provided via the serial commands).

Two of the TTL inputs may optionally be used to control two of the relay drivers, thus allowing for push-button control of the relays at the same time as computer control is occuring

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 motor is still moving. Note that this information is also available from the serial communications subsystem.

Complete control of the motor, including total monitoring of current conditions, is available through the 2400 or 9600 baud serial connection. If you purchase a USB-to-serial conversion cable with drivers, you may also operate our products via USB.

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. Some models may also be configured using a split supply, wherein the motor runs off of a separate DC power supply, while the logic circuit runs off of a 7.5 to 15 volt DC supply.

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

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