Advantech PCL-833 User manual

PCL-833
3-axis quadrature encoder
and counter card

Copyright
This documentation and the software routines contained in the PCL-
833 software disk are copyrighted 1994 by Advantech Co., Ltd. All
rights are reserved.Advantech Co., Ltd. reserves the right to make
improvements in the products described in this manual at any time
without notice.
No part of this manual may be reproduced, copied, translated or
transmitted in any form or by any means without the prior written
permission of Advantech Co., Ltd. Information provided in this
manual is intended to be accurate and reliable. However, Advantech
Co., Ltd. assumes no responsibility for its use, nor for any infringe-
ments of the rights of third parties which may result from its use.
Acknowledgments
PC-LabCard is a trademark of Advantech Co., Ltd. IBM and PC are
trademarks of International Business Machines Corporation. MS-
DOS, Microsoft C and Quick Basic are trademarks of Microsoft
Corporation. BASIC is a trademark of Dartmouth College. Intel is a
trademark of Intel Corporation. Turbo C is a trademark of Borland
International.
Part No. 2005833000 1st Edition
Printed in Taiwan June 1994

Contents
Chapter 1 General information....................................... 1
Introduction........................................................................... 2
Encoder interface ...........................................................................2
Counters .........................................................................................2
Digital input and interrupts ............................................................2
Features.................................................................................. 3
Applications ........................................................................... 3
Specifications......................................................................... 4
Encoder input .................................................................................4
Digital input ...................................................................................4
Programmable interrupt controller ................................................4
General ...........................................................................................4
Block diagram ....................................................................... 5
Chapter 2 Installation....................................................... 7
Initial inspection.................................................................... 8
Switch and jumper settings.................................................. 8
Base I/O address (SW1).................................................................8
Interrupt level (JP1) .......................................................................9
Connector pin assignments ................................................ 11
Connector wiring .........................................................................12
Hardware installation......................................................... 13
Software installation ........................................................... 14
Chapter 3 Operation ....................................................... 1 5
Quadrature encoder introduction ..................................... 16
Counter modes .................................................................... 17
Digital noise filter ................................................................ 18
Latch mode .......................................................................... 19
Counter reset value ............................................................. 20
Reset after latch .................................................................. 20

Cascade mode ...................................................................... 20
Timer function..................................................................... 21
Interrupt function ............................................................... 22
Chapter 4 Programming ................................................ 2 3
Driver programs.................................................................. 24
Basic program structure..................................................... 24
Driver functions .................................................................. 25
Write functions ............................................................................25
Read functions .............................................................................28
Compiling and linking with C compilers.......................... 28
Borland C .....................................................................................28
Microsoft C ..................................................................................29
Chapter 5 Register structure and format................... 3 1
Register format (read) ........................................................ 32
Register format (write) ....................................................... 34
Appendix A 8259A Data Sheet....................................... 3 9

Chapter 1 General information 1
CHAPTER
1
General information

2PCL-833 User's Manual
Introduction
The PCL-833 is a 3-axis quadrature encoder and counter add-on card
for the IBM PC/AT and compatibles (ISA bus). This card lets your PC
perform position monitoring for motion control systems. It provides
three 24-bit up/down counters as quadrature encoders and a 16-MHz
oscillator timebase with wide-range multiplier. An on-board interrupt
controller handles nine different interrupt sources.
Encoder interface
Each input includes a decoding circuit for incremental quadrature
encoding. Inputs accept either single-ended or differential signals.
Quadrature input works with or without an index, allowing linear or
rotary encoder feedback.
Counters
The PCL-833 has three independent 24-bit counters. The maximum
quadrature input rate is 1.0 MHz, while the maximum input rate in
counter mode is 2.4 MHz.You can individually configure each
counter for quadrature decoding, pulse/direction counting or up/down
counting.
Digital input and interrupts
The PCL-833 provides five digital input channels. The channels
accept digital input as an index input for a rotary encoder or as a home
sensor input for a linear encoder.
The card can generate an interrupt to the system based on a signal
from its digital inputs, overflow/underflow of its counters or on a
programmed time interval. It can repeatedly generate interrupts at any
time interval you specify, 0.1 msec to 255 sec. These interrupts let you
precisely monitor the speed of a control system.

Chapter 1 General information 3
Features
• Three 24-bit up/down counters (cascade for up to 48 bits)
• 1.0 MHz max quadrature input rate
• 2.4 MHz max. input pulse rate
• Single ended or differential inputs
• Pulse/direction and up/down counter
• X1, X2, X4 counts for each encoder cycle
• Optically isolated up to 2500 V
• 4-stage digital filter with selectable sampling rate
• 16-MHz oscillator timebase with wide-range multiplier
• On-board interrupt controller with nine different interrupt sources
• Digital input with interrupt for each axis
• Programmable time interval interrupt
• Half-sizeAT-bus card
Applications
• Motion control
• Position sensing, monitoring and measuring
• Coordinate measuring machines
• X-Y table monitors
• Robotics
• Machine control

4PCL-833 User's Manual
Specifications
Encoder input
•No. of Axes: Three independent axes
•Max. quadrature input freq.: 1.0 MHz
•Max. input pulse freq.: 2.4 MHz
•Counts per encoder cycle: 1, 2 or 4 (s/w selectable)
•Encoder type: Single-ended or differential
•Counter size: 24 bits, easily daisychains for up to 48 bits
•Counter modes:
Quadrature, up/down, count/direction (s/w selectable)
•Digital filter: 4 stage
•Sample clock freq.: 8, 4 or 2 MHz (s/w selectable)
•Input isolation: 2500 VRMS using optical isolators
Digital input
•No. of channels: five differential, with interrupt
•Input isolation: 2500 VRMS using optical isolators
Programmable interrupt controller
10-Hz, 1-KHz or 10-KHz time base (s/w selected) with a programma-
ble multiplier from 1 to 255
General
•Connector: DB-25
•Board dimensions: 185 mm x 100 mm

Chapter 1 General information 5
Block diagram
CONTROL UNIT
ADDRESS
DECODER
ADDRESS, DATA AND CONTROL BUS BUFFER
INTERRUPT
CONTROLLER
PROGRAMMABLE
TIME-BASE
GENERATOR
DIFF/SE ISOLATION INPUT CIRCUIT
CH.1 PHASE A
CH.1 PHASE B
CH.1 INDEX
CH.2 PHASE A
CH.2 PHASE B
CH.2 INDEX
CH.3 PHASE A
CH.3 PHASE B
CH.3 INDEX
D/I CH. 0
D/I CH. 1
COUNTER
MODE
CONTROL
DIGITAL
FILTER
24-BIT
UP/DOWN
COUNTER
24-BIT MUTI-MODE
UP/DOWN COUNTER
24-BIT MUTI-MODE
UP/DOWN COUNTER
PC BUS
CONTROL AND DATA BUS

6PCL-833 User's Manual

Chapter 2 Installation 7
2
Installation
CHAPTER

8PCL-833 User's Manual
Initial inspection
In addition to this manual the shipping container should contain the
PCL-833 card and a utility diskette. We carefully inspected the PCL-
833 mechanically and electrically before we shipped it. It should be
free of marks and scratches and in perfect electrical order on receipt.
As you unpack the card, check it for signs of shipping damage
(damaged box, scratches, dents, etc.). If it is damaged or fails to meet
its specifications, notify our service department or your local sales
representative immediately.You will need to contact the carrier so that
it can inspect the shipping carton and packing material. We will then
arrange to repair or replace the unit.
Remove the PCL-833 interface card from its protective packaging
carefully. Keep the antistatic package. Whenever you are not using the
board, please store it in the packaging for protection.
Warning! Discharge any static electric charge on your body by
touching grounded metal before you handle the
board.You should avoid contact with materials that
create static electricity such as plastic, vinyl, and
styrofoam. Handle the board by its edges to avoid
contacting the board's integrated circuits.
Switch and jumper settings
DIP switch SW1 sets the card's I/O address and jumper JP1 sets the
card's interrupt level.
Base I/O address (SW1)
The PCL-833 requires 16 consecutive I/O addresses. DIP switch SW1
(shown below) sets the base I/O address.
1 2 3 4 5 6
ON

Chapter 2 Installation 9
Choose a base address that is not in use by any other I/O device. A
conflict with another device may cause one or both devices to fail.
The factory address setting (hex 200) is usually free as it is reserved
for PC prototype boards.
Jumper settings for various base addresses appear below:
Card I/O addresses (SW1)
Range (hex) Switch position
123456
* 200 - 20F l ¡¡¡¡¡
210 - 21F l ¡¡¡¡l
220 - 22F l ¡¡¡l ¡
230 - 23F l ¡¡¡l l
240 - 24F l ¡¡l ¡¡
×
3F0 - 3FF llllll
¡= On l= Off * = default
Note: Switches 1-6 control the PC bus address lines as follows:
Switch 123456
Line A9 A8 A7 A6 A5 A4
Interrupt level (JP1)
The jumper JP1 selects the card's interrupt level (2, 4, 5, 7, 10, 11, 12
15), as shown below:
Card interrupt (default = 7)
Do not select a level that is being used by another device unless you
have performed special programming to share several devices on one
interrupt.
IRQ 15 12 11 10 7 5 4 2
¡¡¡¡¡¡¡¡
¡¡¡¡¡¡¡¡

10 PCL-833 User's Manual
To use the interrupt you must install an interrupt service routine and
program the PCL-833's on-board the 8259 interrupt controller.
Nine different conditions can enable the PCL-833's interrupt, but only
one at a time.
Interrupt source Condition
0 CH1 overflow
1 CH2 overflow
2 CH3 overflow
3 CH1 ZIN
4 CH2 ZIN
5 CH3 ZIN
6 DI0
7 Shared by TIMER and DI1
Bit 3 of register BASE+9 switches interrupt source 7 between the
card's TIMER and DI1. See Chapter 3 for details.
You should treat all the interrupt sources as positive-edge triggered
when you program the 8259.

Chapter 2 Installation 11
Connector pin assignments
You make all connections to the PCL-833 through a single DB-25
connector, shown below:
Connector pin assignments appear below:
Pin Function
EGND External ground
EVCC External Vcc, DC 5V ± 0.25 V
CH1A- Channel 1 A differential negative- input
CH1A+ Channel 1 A differential positive - input
CH1B- Channel 1 B differential negative - input
CH1B+ Channel 1 B differential positive - input
CH1Z- Channel 1 Z differential negative - input
CH1Z+ Channel 1 Z differential positive - input
CH2A- Channel 2 A differential negative- input
CH2A+ Channel 2 A differential positive - input
CH1A-
EGND
CH1A+
CH1B+
CH1Z+
CH2A+
CH2B+
CH2Z+
CH3A+
CH3B+
CH3Z+
CDI0+
CDI1+
EGND
CH1B-
CH1Z-
CH2A-
CH2B-
CH2Z-
CH3A-
CH3B-
CH3Z-
CDI0-
CDI1-
EVCC
1
2
3
4
5
6
7
10
8
9
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

12 PCL-833 User's Manual
Pin Function
CH2B- Channel 2 B differential negative - input
CH2B+ Channel 2 B differential positive - input
CH2Z- Channel 2 Z differential negative - input
CH2Z+ Channel 2 Z differential positive - input
CH3A- Channel 3 A differential negative - input
CH3A+ Channel 3 A differential positive - input
CH3B- Channel 3 B differential negative - input
CH3B+ Channel 3 B differential positive - input
CH3Z- Channel 3 Z differential negative - input
CH3Z+ Channel 3 Z differential positive - input
CDI0- Digital input No. 0 differential negative - input
CDI0+ Digital input No. 0 differential positive - input
CDI1- Digital input No. 1 differential negative - input
CDI1+ Digital input No. 1 differential positive - input
Connector wiring
External/internal power
If you use an external power supply, connect pins 1 and 13 to external
ground and connect pin 25 to external VCC.
If you use the card's internal power supply, place 0-Ωresistors
(jumper wires) at locations L1 and L2 on board (see labels printed on
board).
Differential/single-ended input
With differential inputs connect the negative wire to the negative pin
and the positive wire to the positive pin. For example, with channel 3
A connect the negative input wire to CH3A- and the positive wire to
CH3A+.
With single-ended inputs connect the input to the positive pin and
leave the negative pin open.
AB phase encoder
In 2-pulse input mode A inputs (CH1A, CH2A, etc.) count up while
their corresponding B inputs (CH1B, CH2B) count down.

Chapter 2 Installation 13
In 1-pulse input mode A inputs (CH1A, etc.) count up or down and B
inputs (CH1B, etc.) determine the direction to count. A logical high
(1) on the B channel indicates that the pulse on the A channel is an up
count, and a logical low (0) indicates that the pulse is a down count.
Hardware installation
Warning! Disconnect power from your PC whenever you
install or remove the PCL-833 or its cables
Installing the card in your computer:
1. Turn off the computer and all peripheral devices (such as printers
and monitors).
2. Disconnect the power cord and any other cables from the back of
the computer. Turn the chassis so the back of the unit faces you.
3. Remove the chassis cover (see your computer users guide if
necessary).
4. Locate the expansion slots at the rear of the unit and choose an
unused slot.
5. Remove the screw that secures the expansion slot cover to the
chassis. Save the screw to secure the PCL-833.
6. Carefully grasp the upper edge of the PCL-833 card. Align the
hole in the retaining bracket with the hole on top of the expansion
slot, and align the gold striped edge connector with the expansion
slot socket. Press the board firmly into the socket.
7. Replace the screw in the expansion slot retaining bracket.
8. Attach necessary accessories to the card.
9. Replace the chassis cover. Connect the cables you removed in step
2. Turn on the computer.
Hardware installation is now complete.You can now install the
software driver as described in the next section.

14 PCL-833 User's Manual
Software installation
The utility diskette included with the PCL-833 holds a test utility
program, example programs and driver programs. We supply the
driver as C source code for Borland and Microsoft compilers. To use
the driver you compile it along with your program.
See Chapter 4 for more information.
The following table describes the contents of the disk.
Program Description
833test.exe Tests most of the PCL-833's functions
833demo1.c Example program which uses the PCL-833 driver to
perform A B phase encoding on 3 channels
833demo2.c Example program which performs 2-pulse encoding on
a 48-bit counter (Channel 1 cascades into Channel 2)
833demo3.c Example program which shows how to use card's
interrupt functions
833tc.c Software driver program for Borland Turbo C and
Borland C compilers
833mc.c Software driver program for Microsoft C compilers
Make a working copy of the master disk and store the master disk in a
safe place.You can use COPY or DISKCOPY to copy the disk files to
another floppy disk or use COPY to copy the files to a hard disk.

Chapter 3 Operation 15
CHAPTER
3
Operation

16 PCL-833 User's Manual
Quadrature encoder introduction
In typical closed-loop control systems, also know as servo systems,
the encoder interface senses motor position and sends a position signal
to the controller. The diagram below shows a typical servo system.
The encoder generates pulses which indicate the shaft position. The
encoder output includes two signals, commonly called channelA and
channel B, which generate N pulses per revolution. The two signals
are shifted by a quarter of a cycle, as shown below. The shift between
the two signals enables the controller to determine the direction of
rotation, depending on whether channel A leads channel B or vice
versa.
HOST
CPU
QUADRATURE
ENCODER
(MOTER)
PHASE A
PHASE B
INDEX
QUADRATURE
SIGNAL
QUADRATURE
SIGNAL
PCL-833
ENCODER
CARD
MICROCOMPUTER
BUS