•	Tuesday, 22 October 1996							

INTRODUCTION

CASA’s Stepper Motor Controller Unit is designed to provide an integrated, versatile and flexible Microprocessor Based Controller for Single, Dual and Tripple, Bipolar Stepper Motors to serve a wide range of Industrial Automation functions and other processes at an economical price.

SPECIAL FEATURES INCLUDE

a) ASCII Command Programmable from any PC or Terminal via RS-232c port (9 pin D-Sub connector)
b) Flash-ROM Storage for storage of program commands enables completely stand-alone operation
c) Ramp-Up and Ramp-Down (acceleration) profiles adjustable to suit any stepping motor and load condition
d) 4 Signal & switchable I/O ports for remote command signals (up to 8 are available)
Stall / Dwell / Pause functions for refined control and protection etc.
e) Optional remote operator panel for "Start, Stop, Pause, Re-Set" push buttons
f) Optional in-puts for Chopper Encoded signal (this version is recommended for critical applications)
g) Custom programming and packaging can be undertaken to suit special applications and environments etc.
h) New Zealand designed and manufactured (servo motor option is also available for special applications)

PRODUCT OVERVIEW

A single selfcontained Aluminum Box contains the SMCU electonics and power supply which provides a comprehensive facility for controlling 4 or 8 wire Bipolar driven Stepper Motors of up to 4 Amps (depending on duty rating and number of motors connected). With installed options up to 3 motors can be controlled from a single SMCU Box.

Simple software commands can be sent from a PC via the RS232.Serial Port to the SMCU can control motor direction, number of steps, start and stop ramp length  and Stepper Motor park current etc. All commands can be stored within the controler to provide Stand-Alone operation.

Custom configuration for specific Stepper Motors can be readily undertaken by choice of limiting resistors which are installed prior to delivery.

Custom and future developments in software and firmware can be implimented by field upgrades of the EPROM.

Future “Daisy-Chaining” of multiple SMCU using RS422 interface are proposed. This will enable complex and sophistocated machines to be created, programmed and expanded on demand.

SPECIFICATION

MOTOR DRIVE

4 or 8 wire bipolar current switching up to 5 ampere per phase Voltage 34 DC (maximum) with other Voltages & Current Ratings to suit Customer requirements. The modular design permitts production of custom units which are affordable even in small quantities.

INTERFACE:

RS232C, 9800 Baud, DTE via 9 pin "D-Sub" connector, Tx, Rx & GND active (Null modem) from SMCU to IBM PC or Intelligent Terminal.

MOTOR CONTROL: 

Speed, direction, 1/2 step, current boost, number of steps (O-99999), ramp (length and slope), limit switch interaction (stop, reverse etc.)

FRONT PANEL BUTTONS

Once programmed, the 2 to 8 front panel (or remote control) buttons and Indicator Lamps facilitate and show the status of all process sequences and controls. Population of the 8 holes depending on the Firmware installed and Customer requirements.

The available buttons are as follows:

	RESET		Reset the system before a pre-programed sequence begins
	START		Begin program execution (once initialized or reset)
	PAUSE		Pause the executed program no matter where it is (pressing 				PAUSE again or START “Un-Pauses the )
	JOG       		Continues executing of the program sequence so long as 				the button is held down
	STOP			Immediately HAULTS the program, stops the
				motor and switches full current off.

SOFTWARE COMMANDS

All software commands are sent from the host terminal or Personal Computer via the RS232 interface. The following commands are deployed:-

A =
L = List current loaded programme
E = Store the currently entered programme list (overwriting previously stored list)
F =
G =
T = Test (performs pre-defined initialization + basic test of controller + attached motors)
X =
Y =
X =

Command characters are foIlowed by return <CR> or Ilnefeed. TheSMCU will echo the command and the SMCU response back to the Terminal or PC.

SOFTWARE OPTION COMMANDS

The following commands select card parameter options associated with motor current, 1/2 or full step, ramp length and slope. (If no specified default settings would apply - See page 7)

u  w  x  y   D  o  <CR>
LH

MOTOR CONTROL OPTIONS

Carriage return I linefeed
Command letter (Option Oy
(Any character = 72 step)
Current boost for ramp length (O = NO 1= YES)
Revised motor current when stopped (Q:E NO 1 = YES)
Motor current off when stopped (t= NO I YES)
Current Boost when running (0 = NO 1 = YES)

SELECT RAMP LENGTH AND SLOPE

K xx L x y F o <CR>

Carriage return / linefeed
Command letter (option F)
0 - 9. Rate (slope) of ramp
0-999. Length of ramp (steps)

POLL SPECIFIED CARD

SELECT MOTOR MOVEMENT COMMANDS

MOVE ANTICLOCKWISE

Carriage return I linefeed

Number of steps (0 99999)

MOVE CLOCKWISE

Carriege return I linefeed <CR>
*EMove
Number of steps (0 99999)

x x x x.Ex E 0 <CR> 

MOVE ANTICLOCKWISE

SPECIFIC NUMBER OF STEPS

x x x x x G 0 <CR> 

MOVE CLOCKWISE

SPECIFIC NUMBER OF STEPS (0-99999) or until the limit switche is activated

PROGRAMMABLE MOTOR SPEED CONTROL

Programming command H has been assigned to provide several pre-programmable motor speeds.

The format of the command is

x H 0 <CR>

L L- Carriage
Motor speed. settings are
1 = 4,800 steps per second
ditto
2 = 2,400
3=1,200
ditto
4 = 600 ditto
Command letter (Option H)
5 = Motor speed
6 = 300 ditto
7 = 150 ditto

INSTALLING “TARG” TERMINAL SOFTWARE

“TARG” is the supplied Terminal software for installation on IBM PC or XT or AT or 386 or 486 or 586 etc. and may be used where users don’t already have a preferred alternative.

SETTING or CHECKING MOTOR CURRENT

In the event that the SMCU is not factory pre-defined (or you wish to check the optimum performance of your specific steppper motor) technically qualified users may check and adjust the value of the Limiting Resistors to suit specific needs.

Equipment required includes and Oscilloscope and substitute Limiting Resistors etc. if required

For example if the motor winding recommended current is 1 Ampere per phase then voltage present across the Limiting Resistors is given by the formula:-

V(Voltage accross Limiting Resistor)

		=	I (Motor rated current Amps) x R(Value of Limiting Resistor) 

The value of the Limiting Resistor can thereby be adjusted to suit the Motor.

LIMIT SWITCH FUNCTION + CONNECTION

The limit switchs may be enabled in Software and is connected to Pins “x + y + z “of the 25 pin D-Sub connector on the rear panel.

A “NC” (normally closed) switch can be used to activate:-

a) Reverse Motor direction
b) Reset the system and await a “START” signal
c) Stop / Pause and await an “Un-PAUSE” signal

A “NO” (normally open) switch can be used to activate:-

a) Reverse Motor direction
b) Reset the system and await a “START” signal
c) Stop / Pause and await an “Un-PAUSE” signal

SERIAL PORT SETUP (COM 1)

The required Serial Port parameters are as follows:-

9600 Baud
8 Bits
No Parity
1 Stop Bit

Connections to host PC or Terminal can be made using either a Null Modem or Data Link CabIe via 9 way “D-Sub” serial socket with RX=Pin2, Tx = Pin3 & GRD = Pin5. DTR is linked to CTS on the PCB and RTS is at 12V DC.

DEFAULT SETTINGS

Unless pre-programmed at the Factory to Customers requirements, on initial power up (connect the motor plus mains supply and turn on) the SMCU has the to the following default settings:-

Full step mode
No Ramp (motor accelerates under load inertia)
Motor current OF when stopped (limits overtemperature at the sacrifice of detent force).
1/2 step Current boost for ramp OFF

WARNINGS AND SAFETY INFORMATION

1) Stepper motors and the Limiting Resistor attached to the heatsink may get very HOT
2) Ensure motors are not over driven. Refer to motor manufacturers specification and ensure the SMCU is well ventilated (fan cooling can be added where necessary).
3) WARNING high voltages are generated on by the Stepper Motor Back EMF and are present at the internal PCB assemblies and on the D-Sub 25 pin connector and motor wiring. Allow time for the magnetic fields to decay and caps to discharge after disconnecting the power and or before disconnecting the motor.
4) DO NOT connect or disconnect the motor with power supplied to the SMCU
5) The MAXIMUM motor drive voltage is 34 V but higher voltages are available.
6) Ensure that only the prescribed mains input fuse is used.
7) The SMCU and stepper motors generate significant RFI (Radio Frequency Interference) and appropriate screening is recommended where sensitive electronic or communications apparatus is present in the same environment.

NOTES

1. If Limit switches are used and motor drive options E or F are specified then the ramp parameters are disabled except that where a Ramp has been programmed the motor speed will start at, and remain at the motor start datum speed appropriate to the ramp specified.

2. Ramp Parameter ratio of 200:1

If Ramp length + Ramp rate > 200 than the motor will be driven at the motor start datum speed until the ratio is equal to or less than 200 and then the ramp up will apply.
Therefore if a ramp length of 500 steps is chosen with a rate of 2 the rate will be 250 and the motor will run for 100 1/2 steps at datum speed until the ratio is 200 whereupon the motor speed wiIl increase at the chosen rate until the ramp length has been achieved.

PSU - POWER SUPPLY SUB-SYSTEM

The SMCU Power Suppy Unit comprises an un-regulated 34V DC (transformer isolated) output for the Stepper Motor and a Low Current 5VDC regulator for the SMCU Microprocessor PCB Assembly.

INPUT 230~240 Volt AC @ 50/60Hz
Motor Supply OUTPUT 34VDC @ 3.5 Amps (maximum)
Microprocessor and Logic Supply OUTPUT 5.0V @ 100mA (maximum)

A circuit Schematic is included in the appendix of this manual.

NOTES

1) For “D-Sub” pinout to Motor, Remote Control Panel and limit switches see schematic diagram in apendix.

Although the motor supply is only rated at 3.5 Amp. this should be sufficient to run most 5 Amp per phase stepper motors.

DIMENSIONS

Length =	250mm (plus connectors external cabling and push buttons etc)
Width =	177mm (plus heatsink or heatsinks if 2 or 3 axis)
Height =	55mm

WEIGHT =	2.7Kg (typical 1 axis), 3Kg (typical 2 or 3 axis)

STEPPER MOTOR CONNECTIONS

WIRE CONNECTION

1. The SMCU is not suitable for 5 wire motors.
Reversing the wires of any one phase will reverse the direction the motor rotates in response to commands.
8 wire parallel connections give higher rotational speeds.
8 wire series connections provide higher motor torque.
Always refer to motor manufacturers data to identify colour codes etc.

GENERAL NOTES

1) The stepper motor chosen for use with the SMCU must be fully compatible with Bipolar drivers.
2) Motor torque is directly related to motor current and is also motor speed related.
3) Torque is proportional to current and inversely proportional to speed.
4) The effective motor impedance is proportional to the load and the speed of the motor.
5) The SMCU will suppty sufficient current for motors specified at 5 Amp per phase. Motors with higher current requirements can be driven but they will not run at full power. Other Power Supply Units are available to support these larger motors.
6) Ramps are used to overcome motor resonance and provide increased starting torque. Current boost is dependent upon suppy voltage and the Limiting Resistors.
7) Avoid running the motor at high temperatures (See motor manufacturers specification).
8) Stepper motor drivers generate large amounts of RFI and while the standard SMCU  enclosure provides significant screening. In critical environments a more adequately screened enclosure with additional EMI filtering and ventilation can be supplied.
9) The SMCU does get hot and generates high discharge voltage. Take all reasonable precautions when using and ensure that temperature do not exceed 55 deg C  

PROPOSED REAL-TIME CONTROL PROGRAMME

INTRODUCTION

The proposed SMCU.EXE program is a simpIe self contained RS232 communication utility with built in Real Time Command Programming functions. This will allow users of the SMCU stepper motor controller to get a remote controlled system up and running with little effort. It offers remote controll all the functions and features of the SMCU to the user by assigning the various commands to function keys and asking for the required parameters where necessary. The software can be used in two modes. Normal mode allows the control of up to 3 Stepper Motors while test mode allows emulation of the SMCU software without the need for a SMCU to be connected.

To run the software in test mode enter the following at the DOS prompt : C:\> SMCU/T. To run the software in REAL-TIME control mode, enter the following at the DOS prompt: C:\> SMCU

A 	F1 Move Anticlockwise
C 	F2 Move Clockwise
E 	F3 Move Anticlockwise or untiI limit switch operates
G 	F4 Move Clockwise or until limit switch operates
D 	F5 Set-up motor control options..
F 	F6 Set-up Ramp length and slope

Each of the above commands will ask for any required parameters end will wait until the command has finished and the SMCU is ready for another command before continuing.

An additional mode is included in the software in which the motor can be driven using the Left and right cursor keys and displays the total offset from the start position. Each press of left or right cursor keys moves the motor 10000 steps in the chosen direction (left cursor = clockwise right cursor = anticlockwise). The number of steps can be changed using the PgUp and PgDn keys. The total number of steps moved is displayed with the direction. It also allows the motor to be automatically moved back to the
zero" reference point. This is a simple way of checking the repeatabiIity of the mechanical system attached to the motor.

UNDERSTANDING THE SOFTWARE COMMANDS

There are two motor drive option commands, options D and F.
Option 0 has 5 sub-options
Sub-option "U" selects 100% motor current when running (It not selected motor runs at 66%).
Sub-option "W selects motor current Off when motor stopped.
Sub-option Ex" selects 1A motor current when motor stopped
Note: If both options “w”" and “x” are selected then option "w' will override optipn "x”.
Sub-option “y” selects current boost for ramp length.
Sub-option “z” selects 1/2 or full step. 0 = 1/2 step 1 = 1/2 step.
All sub-options are selected deselected by 1 or 0.1 select 0 = des elect
Option F has two sub-options
Sub-option “xxx" can be specified between 001 and 999 to set the length of the ramp. (number of 1/2 steps)
Sub option “y” can be specified between 1 and 9 to set the slope of the ramp.
(See page 11 for further exptanation of ramp settings).

There are four movement command options A, C, B, G.

A and E give anticlockwise movement.
C and G give clockwise movement;
Command option A specifies anticlockwise movement for 1 to 99999 steps
Command option C specifies clockwise movement for 1 99999 steps
Command options E and G specifies anticlockwise or clockwise movement for 1 to 9999.9 steps or until the limit switch opens, which ever event happens first. (No Ramp; stays at start speed).

WARRANTY

By this Consumer Guarantee CASA Modular Systems guarantees this product to be free of defects in materials and workmanship at the time of its original purchase from the Seller/Retailer for the period of one year. If during this period of guarantee the product proves defective due to improper materials or workmanship CASA will without charge for labour or parts repair or (at its option) replace this product or its defective parts on the conditions set out below.

1. The customer will not alter, adapt, change or in any way adjust the product, except by technically qualified persons and as detailed In this manual.

2. This Warranty does not cover:-

a) Maintenance or replacement of parts due to fair wear and tear.
b) Home service or transport costs to the Dealer
c) Damage to this product resulting from a) abuse or misuse by the customer.
including failure to follow Greenwich Instruments instructions In the user manual or
d) the Installation or use of the product In a manner inconsistent with the technical
or safety standards in force at the time.