USER'S MANUAL
FOR
VMC-SMC
STEPPER MOTOR
CONTROLLER INTERFACE
FOR
VMC-8509 KITS
PERIPHERALS PVT. LTD.
WB-10, Shakarpur, Delhi-110 092.
Phone : 91- 11- 22462826
Fax : 91-11-22515127
E-mail : vinytics@vsnl.com
Website : www.vinytics.com
Vinytics VMC-SMC User’s Manual
Table of Contents
INTRODUCTION ......................................................................................... 1
SPECIFICATION ........................................................................................ 1
FEATURES................................................................................................ 1
WORKING OF STEPPING MOTOR ........................................................... 2
Starting and Stopping Under Load ....................................................... 4
Speed Control of Stepper Motor ........................................................... 4
OTHER INSTRUCTIONS ............................................................................ 7
Connector Details ................................................................................ 8
VMC-SMC User’s Manual VMC-SMC User’s Manual
STARTING AND STOPPING UNDER LOAD INTRODUCTION
There is a limit for every type of stepping motor as regards the Digital control systems have come to stay. They are entering into all
speed at which it will start and stop without loosing step. The limit is branches of engineering. There are many systems to monitor various
due to load torque as well as load intertie. To overcome this processes and give out control signals in the form of digits but there
acceleration and declaration techniques have to be employed. is only one device to convert these digital pulses into precise
Acceleration means stepping rate on switching should be very low incremental motion and that device is stepping motor. Stepper
and should increase to desired level gradually depending on inertia motor is a device which converts digital pulses into precise angular
to be encountered. Acceleration/deceleration may be as high as or liners steps of desired value.
1000 to 3000 steps/sec.
SPEED CONTROL OF STEPPER MOTOR SPECIFICATION
The program initializes the 8255 (P1) in order to make port. A as q Permanent Magnet D.C. Stepping Motors two phase Bifilar wound.
output port. The PA0 to PA3 is connected through buffer and driving q Step angle : 1.8° ±5% Non-cumulative.
circuit to the winding of the stepper motor. The codes for clockwise
q Step/Revolutions : 200.
movement of stepper motor are FA, F6, F5 and F9 (refer switching
sequence). These code are to be output in the sequence they are
written. In case of anti-clock wise movement of the stepper motor, FEATURES
output codes are as F9, F5, F6 and F4. The delay routine is called v Instantaneous response to control pulses.
to generate the delay (max. of about 1 Sec.) between the steps.
v Holds on to the position infinitely in static condition.
This delay can be changed to make faster steps. The minimum
delay depends upon the maximum speed of the stepper motor v No burn-out due to locked rotor.
specified. v Speed can be varied over a wide margin from 0-10,000 steps/
sec. Equivalent to 0-3,000 RPM.
The speed for steps can be varied by changing the content at 2031-
2032 and 2037-2038. These values are taken by register pair DE v High torque to inertia ratio. Can be over-driven without damage.
and a corresponding delay is generated. Both the delays are added v Can be programmed in three parameters namely, speed, direction
up to give the final delay. The individual delay can be calculated by and number of steps.
(24N + 17) X basic Machine Cycle, N#O. When N is the number
Stepping Motors differ from conventional Servo Motors in following
stored in D register pair.
respect :
Ø There is no control winding in stepping motors. Both windings are
The following is program for Vinytics 8085 Kits. Identical.
Starting address of the program : 2000 Ø The stepping rate (speed of rotation) is governed by frequency of
switching and not supply voltage.
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VMC-SMC User’s Manual VMC-SMC User’s Manual
Switching Sequence
PHASE-1 PHASE-2
STEP SW-1 SW-2 PH-1 PH-2 A-2 B-2
A-1 B-1 A-2 B-2
1 1 2 1 0 1 0 0 1 0 1
2 1 4 0 1 1 0 0 0 0 1
3 3 4 0 1 0 1 1 0 0 1
4 3 2 1 0 0 1 1 0 0 0
1 0 1 0
0 0 1 0
0 1 1 0
0 0 1 0
0 1 0 1
The above switching Sequence/Logic will move shaft in one direction.
Ø A pulse input two phase clock (instead of continuous pulses) will
To change direction of rotation read the sequence upward.
move the shaft of motor by one step for every pulse, thus number
of steps be moved can be precisely controlled. The specified torque of any stepping motor is the torque at stand still
Ø When there is no pulse input, the rotor will remain locked up in (holding torque). This torque is directly portional to the current in the
the portion in which the last step was taken since at any time two winding. The current in winding is governed by the D.C. resistance
windings always energized which lock the rotor of winding. As the switching sequence starts the inductive reactance
electromagnetically. of the winding which increases with the frequency of switching
opposes the rise of current to desired level within the time given for
Ø Stepping motors can be programmed in three parameters namely:
one step depending upon the speed of stepping. This is mainly due
a) Direction, to L/R time constant of winding. The drop in current level causes
b) Speed and drop in torque as the speed increases. In order to improve torque at
c) Number of Steps high speeds it is necessary to maintain current at the desired level.
This can be done by one of the following methods:
WORKING OF STEPPING MOTOR 1. By increasing supply voltage and introducing current limiting
The stepping action is caused by sequential switching of supply to resistances in each phase. Introduction of resistances improves
the two phases of the motor as described in switching diagram. All the time constant of winding. Seven to nine time the winding
stepping motors are of bifilar type with six leads. Watch of the two resistance in each phase will give very good improvement in
Phases of motor has double winding with a centre tap switching the torque/speed Characteristics.
supply from one side to another of a phase causes reversal of 2. By using a constant current source with or without a chopper
magnetic polar without actually reversing the polarity of supply. For instead of using a constant voltage source which will give even
step input sequence gives 1.8° (full) after and eight step input better performance.
sequence give 0.9° (half) step function.
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VMC-SMC User’s Manual VMC-SMC User’s Manual
PROCEDURE
Connector Details at CN1
1. Switch on 8085 kit.
PC4 PC5 2. Connect 26 pin FRC cable from 8255-I connector of kit to 26 pin
PC2 PC3 connector of SMC Card at CN1 Connector.
PC0 PC1 3. Connect Stepper motor cables to given stepper motor card at
PB6 PB7 CN4 connector.
PB4 PB5 4. Connect stepper motor power supply connector at CN2 connector
PB2 PB3 of SMC module.
PB0 PB1
5. Enter the given program from 2000 Address and Execute from
2000 Address.
PA6 PA7
6. See the speed of motor as defined delay.
PA4 PA5
PA2 PA3
PROGRAM
PA0 PA1
PC6 PC7 2000 3E 80 MVI A,80 Initialize all ports as out
ports.
GND GND
2002 D3 03 OUT 03
2004 3E FA START: MVI A,FA
2006 D3 00 OUT 00 Output code for step 0.
2008 CD 30 20 CALL DELAY Delay between two steps.
200B 3E F6 MVI A,F6
CN2 200D D3 00 OUT 00 Output code for step 1.
+5V
GND 200F CD 30 20 CALL DELAY Delay between two steps.
Motor
U1 U2 U3 U4 Supply 2012 3E F5 MVI A,F5
NC
2014 D3 00 OUT 00 Output code for step 2.
1 2 2016 CD 30 20 CALL DELAY Delay between two steps.
2019 3E F9 MVI A,F9
201B D3 00 OUT 00 Output code for step 3.
U5 201D CD 30 20 CALL DELAY Delay between two steps.
2020 C3 04 20 JMP START Start.
SUPPLY
Delay Routine
MOTOR
GND
GND
GND
GND
PA1
PA2
PA0
PA3
PA1
PA2
PA0
PA3
25 26
2030 11 00 01 DELAY: LXI D,0100 Generate a Delay.
CN1
CN4 CN3 2033 CD A6 03 CALL DELAY
2036 C9 RET
STEPPER MOTOR To move the Motor in the reverse direction, Change the contents at
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VMC-SMC User’s Manual VMC-SMC User’s Manual
the addresses as mentioned below :
Address Forward Reverse
2005 FA F9
200C F6 F5
2013 F5 F6
201A F9 FA
STEPPER DRIVER
0 . 1 µd
VOLTAGE 5 TO 36V
F The 7Pin Connector Details of CN4 are as follows : Ω
1 0 0Ω
Ω
5 6 0Ω 1W µd
0 . 1µ
ECP 055
Ω
CL100 2 7 0Ω
330Ω
Stepper Motor Voltage: 12/5 V as per the Stepper Motor
PA0 Amplified Output
PA1 Amplified Output
PA2 Amplified Output Ω,1W
Ω,
10Ω,
PA3 Amplified Output
MOTOR GND GND PA1 PA2 PA0 PA3
SUPPLY
THE CIRCUIT REMAINS SAME FOR ALL FOUR WINDING
THE INPUTS ARE TAKEN FROM PA1, PA2 AND PA3
Note : To change the speed of the stepper motor, change data at memory
location 2031 and 2032 in the programme.
e.g. 2031 00,
2032 02
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