WYFFOS - SMD4 THREE AXIS 4 PHASE STEPPER MOTOR DRIVE CARD
WYFFOS - SMD4 THREE AXIS 4 PHASE STEPPER MOTOR DRIVE CARD
DRIVER
Contents:
- 1. Introduction
- 1.1 Document History
- 1.2 Version notes
- 1.3 Mnemonics used throughout the text
- 2. Circuit Description
- 2.1 Physical
- 2.2 Electrical
- 3. Circuit diagrams
- 3.1 Drive 1
- 3.2 Drive 2
- 3.3 Drive 3
- 3.4 Interface and Power Supplies
- 4. Parts list
1. Introduction
The SMD4 three axis 4 phase stepper motor drive card has
been designed to provide three independent drive circuits
to control four phase stepper motors with a phase current
of less than 1.25amps. In the WYFFOS instrument it is
used to control the two filter slides and the slit focus
which are all moved by 4 phase linear actuators.
1.1 Document History
- Version 1.0 first issue March 1995
1.2 Version notes
- V1.0 first official copy.
1.3 Mnemonics used throughout the text
- WYFFOS Wide Field Fibre Optic Spectrograph
- LIMPIT Local Instrument Motor Positioning Interface Terminal
2. Circuit Description
2.1 Physical
The circuit card is a 3U x 160mm eurocard with a DIN 41612 edge connector and
is mounted vertically in the WYFFOS LIMPIT sub-rack. A free flow of air around the
card is required, forced cooling is unnecessary
2.2 Electrical
The circuit consists of three identical drives therefor only one drive
shall be explained. The drive has four inputs : Enable, Direction,
Step and Half/Full. Each input is via an opto-coupler with a series
resistor so that they can be driven from any 5V signal which does not
need to be referenced to the same supply that provides the power to the
card and the motors. Each output from the opto-couplers is pulled-up and
input to and exclusive-OR gate. The other input to the exclusive-OR
gate can be selected to be a logic 1 or logic 0 by either fitting or
removing a jumper link. This has the effect of either inverting or not
inverting the sense of the input signal. This enables the card to be used
with different controllers that may have different sense outputs. The
outputs of the logic gates are then feed into the 4 phase drive chip (UCN5804B)
with the inclusion of pull-up resistors as the UCN5804B inputs are CMOS level
and are being driven by LS gates.
The UCN5804B has six output connections, one for each of the phases
(OpA, OpB, OpC and OpD) and two commons (Kac, Kbd). When the enable is
set and a clock is applied to the step input then the four outputs are
grounded in sequence energizing the coils of the motor causing it to
rotate. A copy of the manufactures data sheet is included in Appendix A
for further details.
In the WYFFOS application the motors used have 12V coils and do not require
a series resistor. From previous experience it has been found that the
drive chips can be damaged when they are enabled with a voltage applied to
the Kac and Kbd pins and no connection to the outputs. To avoid this the 12V
supply is connected to the drive chip via all the connectors that connect
the motor to the drive chip therefor if the motor is disconnected then the
12V is also removed from the drive chip. An example of the connections are
shown below.
3. Circuit diagrams
3.1 Drive 1
3.2 Drive 2
3.3 Drive 3
3.4 Interface and Power Supplies
4. Parts list
Circuit Component Manufacturer & Supplier No. Cost
Ref. part & order off per
number code item
100 x 160 Bicc Vero Electrosp 1 £8.49
circuit board 03-0026J eed
03-0026J
Card Ejectors Bicc Vero Electrosp 1 £1.29
173-26513C eed
173-
26513C
J1 Connector Harting Electrosp 1 £4.28
class 2 0903.164.6928 eed
W/wrap 64/96 17-1222E
U1,U3,U Translator/Dri Allegro RS 3 £4.39
5 ver Microsystems 653-531
U2,U4,U 2 input XOR Motorola RS 3 £1.66
6 gate IC. SN74LS86N 644-234
RP2,RP4 4 Individual Beckman RS 3 £0.18
, 470R SIL Industrial 168-601
RP7 package L83S471
RP3,RP5 8 Common Beckman RS 3 £0.21
, 4K7 SIL Industrial 140-962
RP8 package L91S472
RP1,RP6 8 Common Beckman RS 2 £0.21
10K SIL Industrial 140-978
package L91S109
ISO1,IS Opto-Isolator Sharp RS 3 £1.59
O2, PC847 175-132
ISO3
JP1 - PCB Jumper RS 1 £3.71
JP12 Header 334-549
Jumper Links RS 12 £0.38
334-561
C1,C3,C 0.1µF AVX Kyocera RS 6 £0.602
5, decoupling 125-806
C8,C9,C capacitor
10 ceramic
C2,C4,C 200µF 25V Panasonic RS 3 £0.286
6 Electrolytic 107-038
C7 470µF 25V Panasonic RS 1 £0.382
Electrolytic 107-044
Original Document smd4.doc by M. A. Parr RGO Cambridge
Converted to HTML by M. A. Parr map@mail.ast.cam.ac.uk