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General STD Bus Information
 What is STD Bus?
What is STD32?
Why use an STD Bus system?
About the STD Bus FAQ
Contribute to the FAQ
STD Bus related information on the Internet
The STD 32 Manufacturer's Group
The STD Bus Specifications
Shows, conferences, seminars
Trade Journals
Technical Books
STD Bus Questions and Answers
What's the maximum number of STD boards in a card cage?
Should a custom designed card be considered?
What is signal Conditioning?
What are the STD Bus pinouts?
Is the STD bus supported by a large enough vendor base?
What types of boards are offered for the STD bus?
What type of power does the STD Bus require?
Driving large loads
What is the most common media used in Solid State Disks (SSDs)?
What about SSD and a real-time operating systems?
Year 2000 issues in embedded systems
The Five Steps to Data Acquisition
Collecting data from an IP address (Ethernet or Internet) directly into Access, Excel, etc.
Making data from my RS232 device available at an IP address on a TCP/IP network
The STD bus is a standardized computer bus archetecture which is based
on a passive backplane shared by a number of circuit boards to create
a flexible computer system.
STD bus began in 1978 with the initial 8-bit STD Bus specification created by Mostek and Pro-Log, now called STD-80.
In the earily years, the STD bus was second only to IBM PC's ISA bus in popularity.
At one point there were more than 100 vendors of STD bus products globally.
The STD bus gained popularity because of its rugged construction, relatively small card size, industrial grade components with
wide temperature range combined with low power consumption.
These features lead to success in applications such as power and chemical plants, factory automation, medical equipment, and
heavy machinery control.
Eventually 16-bit data transfers were added to the STD-80 using a multiplexing scheme.
Some vendors created minor variations to the bus for specialized purposes such as taking advantage of a new processor
or to increase transfer rates.
In the late 80's, Ziatech (Now owned by Intel and not producing STD/STD32 products) built upon the STD-80 8-bit specification
and introduced STD32 which added 16-bit and 32-bit data paths while allowing backward compatibility with 8-bit systems.
This was accomplished using a fancy bus connector similar to that of the EISA bus where pins on the bus connector make contact with
different board pins depending on the features of the card.
Currently, STD-80 and STD32 system popularity is slowly being replaced by newer technology such
as the stackable PC104 systems, various incarnations of the PCI bus, VXI bus and others.
Still, several core vendors exists along with other many smaller vendors that continue to make STD bus products.
A large base of applications still exist in the marketplace which require maintainence and upgrades.
From a software standpoint, STD-80 and STD32 systems run various real-time operating systems, popular
operating systems such as MSDOS, Windows and Unix, or simply custom code written for a specific application without an underlying operating system.
Processors range from the ancient Intel 8-bit 8080 to newer x86 generation processors, and even motorola 680XX and other types.
Answer provided by Roger Arrick.
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The STD32 standard was created in the late 80's by Ziatech who was a dominate player in the STD-80 marketplace.
STD32 adds many new features to the 8-bit STD-80 standard including 16-bit and 32-bit data paths,
larger memory maps, multiple bus-masters, burst transfers, better interrupt handling, etc.
Backward compatibility with 8-bit cards is accomplished using special bus connectors that
are capable of handling both types of boards using a pin-interleave technology that is similar to the EISA bus and MicroChannel Bus.
Answer provided by Roger Arrick.
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The STD Bus has many features that offer advantages over other bus architectures.
Mature technology proven to work in many applications
STD has been around since the 70's and it's a mature technology.
Millions of STD Bus systems have been launched and still to this day
hundreds of thousands are in operation.
Because of this large deployment, vendors can offer you plenty of advice
on designing your system and minimizing the risk.
With the STD Bus, you're not going out on a limb like some of the newer technologies that
have no long-term track record.
Hundreds of thousands of systems running right now
The STD Bus might not get as much press as the latest sexy buses do, but they are out there
and running in large numbers and have been for more than 2 decades.
Large card counts possible
If your system has a lot of I/O then STD Bus is the answer.
A system can easily have over 20 boards to control everything from
valves, lights, motors, and read analog and digital sensors, cameras and more.
The design of the card cage allows easy cable access to each card.
Plenty of CPU power
High CPU Performance is not a problem on the STD Bus.
An STD bus system can offer you Pentium-class performance, and even multiple processor masters on the same bus!
On the other extreme there's the 8-bit Intel 8085 - why use a Pentium when a lower cost CPU will do the job?
Easy access to cards
Don't underestimate this one.
A single STD Bus card can be removed without distrubing the rest of the system
making an STD Bus system much easier to repair than the newer high-integration single-board computers or stacking-type buses.
The STD Bus is a great decision from a maintenance standpoint because board-level repairs can be made faster and that translates into
less downtime.
Plenty of vendors
At the peak, as many as 150 vendors made STD Bus products. Today it's less but there's still
a core group of vendors that are commited to building STD Bus products and designing new ones.
You can even get Pentium(tm) class CPU cards for the STD Bus - and that's not old technology.
The reason vendors are designing new cards is because the STD Bus is winning new designs from Engineers everywhere.
Very rugged
STD Bus systems are designed to be very rugged, even abused.
They're great for high-temperature applications such as outdoor systems (in an enclosure of course)
such as railroad controls, traffic lights, factory automation, etc.
The heavy-duty design of an STD Bus card cage gives it excellent vibration resistance too.
The Challenge
Engineers should keep the STD Bus on thier list for new system designs.
The data is in, and the STD Bus continues to be a great option.
Answer provided by Roger Arrick.
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What is a FAQ?
Many special interest groups in cyberspace have a FAQ file
(frequently asked questions) associated with them.
This reduces repetitive questions from new users (newbes), reduces
the overall clutter of messages on newsgroups, and generally educates the masses.
In addition to answering common questions, this FAQ will also serve as a
tutorial for those learning about STD Bus systems.
About Roger Arrick
Hello. My name is Roger Arrick.
I'm founder and Engineer at Arrick Robotics
where I design and sell motion control systems.
As an engineer I always collected information about things that interested me and over the years this grew into a pretty large stack.
When the Internet started becoming popular I went publishing crazy and started an on-line publication known as
The E-Zine of Computer Controlled Systems
in which I distribute control-related product and vendor information for several popular computer buses.
The E-Zine has become very popular to both users and vendors.
The STD Bus FAQ is a result of this effort.
Why do I do it?
Why do I go to all this effort and give it away for free?
Well, to enhance awareness, promote the general welfare of
the embedded-computing community, stamp out technical hog-wash, elevate
certain writers to even higher ivory towers, and finally, to be a part of something cool.
Oh, and did I mention it also gives us a warm, fuzzy feeling?
Legal and Copyright information
The official name of this document is:
"STD Bus Frequently Asked Questions (FAQ)
copyright (c) 1995-2002 all rights reserved".
This FAQ is compiled and written by Roger Arrick of
Arrick Publishing with contributions by vendors and
users of STD Bus systems, among others.
This document is Copyright (c) Roger Arrick -
Arrick Publishing all rights reserved.
Please do not distribute this document without express permission from the author.
Please do not remove this notice.
Contact the author via email at
[email protected].
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| Contribute to the STD Bus FAQ |
|---|
We welcome contributions and comments from STD bus users, vendors,
engineers, programmers, and well, you get the idea - everyone.
We're specifically looking for common questions asked about STD bus systems.
The Author will be allowed to place their name, company information,
etc at the end of the contributed text.
This gives companies a little P.R. to justify their effort.
Naturally, self-promotion and marketing hype will not be allowed.
After we receive your contribution, we'll do some minor editing,
check for technical accuracy, add it to the FAQ, and notify you
of your success.
Sorry, we can't use information specific to a certain piece of
equipment or software unless is offers insight on more universal
issues.
We hope you'll consider being a part of this noble effort.
It'll look great on your resume!
Send comments, articles, and information to the editor via email
at [email protected].
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| STD Bus related information on the Internet |
|---|
As you can imagine, the Internet is full of information about
STD Bus and embedded systems. Here are a few links:
Web Sites
FAQs
Frequently asked Questions available for downloading via FTP. You'll
need an FTP (File Transfer Protocol) client or a browser that will
let you download the file and save it.
Newsgroups
You'll need a newsreader or a web browser with one to access newsgroups
also known as USENET. This is where many questions get answered that
are not covered in a FAQ. Most newsgroups have a FAQ associated with
them.
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| The STD 32 Manufacturer's Group |
|---|
The STD32 Manufacturer's Group supports the development of STD32 Bus products and technology.
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| The STD Bus Specifications |
|---|
These documents are in PDF format and require the PDF viewer from Adobe.
STD-80 Specification Section 1 (3meg)
STD-80 Specification Section 2 (3meg)
STD-80 Specification 16-bit transfers (3meg)
STD-80 Z80 Specification (8meg)
These are links to the STD32 Group:
STD32 Short-Form Specification (~250K)
STD32 Specification (~800K)
Also, check the IEEE Standards Association at:
http://standards.ieee.org
Search for '961' to find the description of the IEEE 961-1987 Standard for an 8-Bit Microcomputer Bus System.
IEEE Standards Office
445 Hoes Lane
Piscataway, NJ 08854
Tel: +1 732 981 0060
Fax: +1 732 981 1721
Would you like to see a mechanical drawing of an STD Bus card?
STD-80 Specification Overview
The STD-80 Specifications describes both the physical and electrical characteristics of the system.
This includes the pinouts of the bus connectors, dimensions of the cards, signal timing/drive/loading, and power issues.
Each STD-80 card is 6.5" tall, 4.5" wide, .062" thick.
The minimum spacing between each card in the card cage is .5" with .625" being typical.
The bus connectors have 56 pins (28 on each side) on .125" centers.
Card keying is provided to prevent upside-down insertion.
Most STD-80 systems run on +5VDC only, but the bus also has pins defined for +12VDC, -12VDC
for use with analog and other circuitry, along with a special battery voltage source.
A typical power supply will deliver 5-10 amps on the +5VDC rail and much less on the +/-12 rails.
A typical card cage will have 3-20 slots or even more and often are designed to fit
in an EIA 19" rack.
On high-integration STD bus cards which don't require other cards for support functions, it's
possible to have a single board system without a backplane but only a single bus connector to supply power.
From an electrical viewpoint, the STD-80 bus is designed with Intel's x86 processors in mind.
That doesn't completely exclude the use of other processors, but does make it more complex to make them work due
to differences in memory access timing, interrupt handling, etc.
The bus is a simple single-master setup where the other cards are slaves designed to talk to a single processor.
There is an 8-bit bidirectional data bus, 16-bit address bus, and various control pins
used to control memory, I/O, interrupts, reset, etc.
See the specification document for details about signal timing and drive levels.
Additionally, special methods are defined for 16-bit data access and 24-bit address spaces.
These expanded modes are accomplished with double 8-bit data transfers, and by
multiplexing the new address bits on top of existing address and data pins.
STD32 Specification Overview
STD32 is a specification for updating STD-80 to full 32-bit data transfers, 32-bit
address space, DMA improvements, Interrupt improvements (including slot-specific
interrupt allocation), multiprocessor arbitration, and additional improvements in speed.
STD32 retains backward compatibility with STD-80 8-bit and 16-bit systems by using a
special connector scheme like that found on MicroChannel and EISA buses.
The total pin count increases from 56 to 136.
See the STD32 specification for details about the new signal timing, extended cycles, board modes
and new feature definitions.
Answer provided by Roger Arrick.
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| Shows, Conferences, Seminars |
|---|
Attending a show or exhibition can be an educational and fun experience.
Most major cities are visited by a shows, conference, exhibit or seminar
on a regular basis. The following list describes several shows that would
be of interest to the embedded systems user:
The Real-Time Computer Show
Contact: Cindy Chikahisa at The RTC Group
Ph: (714) 489-7575
Fax: (714) 489-8502
Email: [email protected]
Web: http://www.rtcgroup.com
Embedded Systems Conference
Exhibits, tutorials, classes, speakers, product demos.
When: March 31-April 2, 1998
Where: Chicago, IL
Ph: (617) 821-9210
Fax: (617) 828-9992
Web: http://www.embedsyscon.com
Embedded Computing Shows
Contact: Steve Grimaldi at The RTC Group
Ph: (714) 489-7575
Fax: (714) 489-8502
Email: [email protected]
Web: http://www.rtcgroup.com
IEEE Conference Listings
http://www.ieee.org/conference/conflinks.html
A more complete list of shows can be found at
the
E-Zine of STD Bus Controlled Systems.
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Several industry trade journals cover issues related to embedded computing,
here are a few:
RTC Magazine (Real-Time Computing)
The RTC Group
27312 Calle Arroy
San Juan Capistrano, CA 92675 USA
Phone: 714-443-4400
Fax: 714-489-8502
Web: http://www.rtcgroup.com
Embedded Systems Programming Magazine
Miller Freeman, Inc
525 Market St., #500
San Francisco, CA 94105 USA
Phone: (415) 905-2200
Web: http://www.embedded.com
Back to the top
Several book stores can be found on line that carry technical books
including:
On-Line Book Stores
We think the following books may be helpful to programmers, engineers and users
of embedded systems:
Indispensable PC Hardware Book
Covers the desktop IBM-style PC. Complete PC hardware reference including
interrupt, bus, I/O, EISA/Microchannel/PCI.
Author: Peter Messer
Publisher: Addison-Wesley
ISBN: 0201876973
The Art of Programming Embedded Systems
Author: Jack G. Gansale
Publisher: Academic Press
ISBN: 0122748808
Embedded Systems Programming In C and Assembly Language
Author: John Forrest Brown
Publisher: Van Nostrand Reinhold
ISBN: 0-442-01817-7
Practical Guide to Real-Time Systems Development
Author: Sylvia Goldsmith
Publisher: Prentice Hall
ISBN: 0137185030
Real-time Systems: Specification, Verification, and Analysis
Covers program structures, timing analysis and scheduling theory
and specification and verification using an assertional
method, using Timed CSP and using the duration calculus.
Author: Mathai Joseph
Publisher: Prentice Hall Intl.
ISBN: 0134552970
A more complete list of reading material can be found at
the
E-Zine of STD Bus Controlled Systems.
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| STD Bus Questions and Answers |
|---|
What's the maximum number of STD boards in a card cage?
It depends on both the drive capacity of the CPU board and the loading of the other boards.
It's not uncommon for systems to have 20 or more cards, and it's also common to see
small systems with only a couple of cards.
Systems with high-integration CPU boards can consist of a single card.
Answer provided by Roger Arrick.
Should a custom designed card be considered?
Custom designs can provide precise system requirements by:
- Providing functions that are not available with standard
products; and/or,
- Reducing card count by combining functions of two or more
standard products into a single card.
Most designs can be accommodated by 2-layer and 4-layer PCB's.
Typical cost and delivery for a custom designed card in which
a function specification is provided are as follows:
| # Layers |
Production Prototype |
Additional Units (1-10) |
Delivery |
| 2 |
$1,500-$2,000 |
$175-$225 |
4-5 Wks |
| 4 |
$2,500-$3,000 |
$250-$300 |
4-5 Wks |
Concerning the number of cards usually required to justify the cost of the
production prototypes:
As an example, suppose two standard products are available that
provide a system requirement using partial functions of each card.
Suppose the combined costs of the cards is $375. A 2-layer design
that combines these functions for n units might typically be:
(1) Custom design for n cards = $1750 + (n-1) * $200
where $1750 is the proto and $200 is the additional cost/card.
The two standard units would cost:
(2) Standard products for n cards = n * $375
Equating (1) and (2) we find the break even cost occurs for n = 9.
Thereafter, each card saves $175. In general, typical designs
offer savings at 9 or 10 units.
Answer submitted by John Hilburn
at Microcomputer Systems.
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What is signal conditioning?
More generally, signal conditioning is converting a signal from some
transducer to whatever your receiving system needs. Frequently it's a
matter of amplifying the microvolt or millivolt signals you get from
(for instance) a strain gauge to the 10V span you need to get good
resolution for your analog to digital converter.
However, many transducers give you strange things that you have to
convert. A tougher example is a Linear Variable Differential
Transducer, which gives you a varying AC voltage (after you've
given it a stable AC voltage). The voltage it gives you back varies in
level with the position of the core, so you have to first convert that
AC voltage to DC, then amplify scale it to fit into your ADC's span.
Some transducers give you a current, which you must convert to a scaled
voltage.
These are all examples of signal conditioning, and you'll notice I
haven't yet mentioned "cleaning up."
You frequently want to clean the signal up, too, but that's usually
incidental to the process. Most transducers give a far cleaner signal
than you can use, so the best approach is to protect the signal you
get from the transducer and convert and scale it directly, rather than
trying to clean up a signal that's been contaminated by careless wiring.
Answer submitted by John Hilburn
at Microcomputer Systems.
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What are the STD Bus connector pinouts?
The STD-80 spec defines 56 bus pins.
-----------------------------------------------------------
Component Side Circuit Side
Pin Signal Pin Signal
-----------------------------------------------------------
1 +5VDC 2 +5VDC
3 GND 4 GND
5 Battery 6 Power Down
7 D3, A19 8 D7
9 D2, A18 10 D6
11 D1, A17 12 D5
13 D0, A16 14 D4
15 A7 16 A15
17 A6 18 A14
19 A5 20 A13
21 A4 22 A12
23 A3 24 A11
25 A2 26 A10
27 A1 28 A9
29 A0 30 A8
31 -WR 32 -RD
33 -IORQ 34 -MEMRQ
35 IOEXP 36 MEMEX
37 -INTRQ1 38 -MCSYNC
39 -STATUS1 40 -STATUS0
41 -BUSAK 42 -BUSRQ
43 -INTAK 44 -INTRQ
45 -WAITRQ 46 -NMIRQ
47 -SYSRESET 48 -PBRESET (button)
49 -CLOCK 50 -CNTRL
51 PCO 52 PCI
53 AUX GND 54 AUX GND
55 +12VDC 56 -12VDC
Answer provided by Roger Arrick.
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Is STD/STD32 supported by a large enough vendor base?
STD bus systems are aging but there are still several dozen suppliers globally.
Many of them are committed to provided STD bus products for the long haul.
Answer provided by Roger Arrick.
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What types of boards are offered for STD?
- CPUs including everything from 8085 to Pentium
- Most varieties of serial communications
- AC and battery power supplies
- LCD and traditional CRT video drivers
- Solidstate disk
- Rotating disk storage interfaces
- Adapters to other types of busses
- Real time clocks
- Prototype boards
- Digitial I/O
- Analog I/O
- Sound and speech I/O
- Motion control (servo and stepper)
- Optical encoder interfaces
- Relay and solenoid drivers
- Load cell and other specialized sensor interfaces
- Counter/timers
- Keyboard and keypad interfaces
- Prototype boards
Answer provided by Roger Arrick.
Back to the top
What type of power does an STD bus system require?
Many STD Bus systems only need +5VDC, but some cards require +/-12VDC also.
Especially the ones that contain analog circuitry.
The amount of current needed will depend on the cards used but could
be as high as 10 amps or more on the +5 rail.
Linear and switching supplies
Two common types of power supplies are switchers and linear.
Switchers are now the most popular due to their size and cost.
Linears normally need a larger transformer but supply cleaner
power and offer simplicity of design. Many switchers have
a minimum current draw requirement for them to regulate properly -
make sure to check the specs of your system and supply.
Regulation should be better than 5% in most cases.
Packaging
The power supply on most systems is contained within the STD card cage.
Read those data sheets
It's important to spend a little time and read the vendor's
data sheets carefully for power requirements. It's smart
to have excess current capacity to maintain your future
expansion options. With a little effort, you'll be able
to select a power supply that's right for the job.
Answer provided by Roger Arrick.
Back to the top
Driving Large Loads
Many embedded systems must control large devices such as motors,
lights, valves, etc. Driving such a load is normally done by
attaching a digital output signal to a relay. The relay controls
the large load from the small digital system in the same way
that your car key switch controls your starter through a soleniod.
There are both mechanical and solid-state relays on the market.
Traditional mechanical relays rely on a coil which creates
a magnetic field to cause the contacts to close or open.
These coils normally require even more current than an digital
output signal can provide requiring a buffer circuit in the
form of a transistor. Mechanical relays can obviously wear
out due to the moving parts involved. Contacts in the relay
often arc creating a carbon deposit and electrical noise that
can distrub near-by electrical equipment like the control computer.
Solid state relays
Solid state relays provide the same function as their mechanical
counterpart but without many of the disadvantages.
Since there are no moving parts, the need for contact cleaning
is eliminated. Contact bounce and electrical noise are also
non-existent in solid state models.
Virtually all solid state relays also provide optical isolation
which eliminates the direct electrical connection between the
control computer and the load being switched. This goes
a long way to protect sensitive digital computers and eliminate
load noise from feeding back to the computer.
Solid state relays also don't require as much current as
mechanical models and can usually be driven directly from
a digital output pin.
Digital I/O boards
Many digital I/O boards are available for STD Bus systems. Some
will provide dozens of I/O pins to control devices and read
digital sensors, switches, etc. Multi-function boards are also
available that provide digitial I/O plus analog inputs, timers,
counters, and other useful functions.
Using the parallel printer port
In applications where only a few digital I/O lines are needed,
you may want to check into using a standard parallel printer port.
Printer ports are simply digital I/O board designed to drive
printers. The bits on the port accessed through the control
program just like any other port. Since many single-board-computers
already have such a port, using it for this function could
eliminate the need for additional board on the stack.
Electrical spikes
When large loads are switched ON or OFF, electrical noise and
voltage spikes can be created. If these effects make their
way back to the control computer, it could stop the program,
or worse, distroy circuits. Several devices exist to dampen
spikes including MOVs (Metal Oxide Varistors), and Transzorbs.
Most solid state relays already contain a protection device.
Cable and connectors
Remember to calculate the current needed for your load and
size the cables and wires accordingly. Undersized wires
can melt under heavy loads and cause fires. Connectors
must also be capable of carrying the load.
Grounding
It's normally safer to connect the frame of a machine
having power loads to earth ground. Doing so, prevents
an electrical short from creating an electrical shock
condition for operators.
Answer provided by Roger Arrick.
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What is the most common media used in Solid State Disks (SSDs)?
The most common media in use today for creating solid state
disks is Flash ROMs with some sort of BIOS extension
(for bootable media) or installable device driver (for non-bootable
data storage media).
Most manufacturers provide a BIOS extension that will allow the user to
use the standard DOS/Windows commands and file structure. Assuming
the designer is using DOS, for example, the steps would be as follows:
To make a bootable MS-DOS/Windows device:
Type Format /s driveletter : and this will create an MS-DOS file
structure as well as transfer the operating system to the SSD.
To make a non-bootable device:
Type Format driveletter : Notice that the /s command line
switch is not used in this case so the Operating System is not copied onto the SSD.
Answer contributed by Michael Peat
at INSIDE Technology USA, Inc. .
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What about Solid State Disks (SSD) and a real-time operating systems?
Many single board computer manufacturers provide additional
software/firmware support for a variety of operating systems
that are specific to their hardware.
Another very simple way to implement an SSD for these types of
applications is to use an IDE interface Flash Disk device. These
are available from many of the single board computer manufacturers
as well as third parties. These SSDs greatly simplify system
development by using an IDE port on the single board computer.
Thus, the user would follow the same steps as would be used in
preparing any IDE hard drive for the operating system that is chosen.
Answer contributed by Michael Peat
at INSIDE Technology USA, Inc. .
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Year 2000 issues in embedded systems
The so-called "year 2000" problem is caused when software uses only
2-digits to represent date codes in order to save space in
memory and/or disk.
The obvious problem occurs at the transistion between 1999 and
the 2000.
The year "1999" is stored as "99" and the year 2000 is stored as "00".
Any calculations based on these 2, 2-digit values must take into account
the roll over from 99 to 00 as being only 1 year.
If the program does not contain special code to deal with this
condition, then a calculation could return bad results.
An example
A good example of this would be an embedded system that is used
as a data-logger to track traffic.
A sensor would detect the number of cars traveling a road and software
would count the cars and create reports about the flow over time.
The 1998 new year calculation would be 1998 - 1997 = 1 year using
4 digit values and 98 - 97 = 1 using 2 digit values. The result
of these calculations are the same.
The 2000 new year calculations would be 2000 - 1999 = 1 year,
and 00 - 99 = -99 (woops!). The program could easily detect this
condition and fix the result with the following statement:
"if result <0 then result=result+100".
But often programmers underestimate the longevity of their
creations, lack room in memory, or are simply lazy.
The solution
In order to solve the problem, a programmer must first decide
if the error is taking place in the operating system or in the
application code. The source code would then be modified to
add additional calculations to detect the error and correct for
it.
Under some circumstances, it may be necessary to convert 2-digit
dates into 4-digit dates. This would consume more memory and may
be difficult.
Another potential problem could be caused by the fact that
the software development tools (compiliers, linkers, assembliers, etc)
may have been upgraded and new program construction could cause
other problems.
Those that commented their code and documented their system will
be greatly rewarded with reduced modification time.
The world won't end
In spite of all the panic surrounding the year 2000 problem, I
predict that many people will return to work from new years eve
in the year 2000 and notice either no problem, or that some
report now displays silly results. You may even receive a
notice that your electric bill is -99 years past due.
Phones will ring, Programmers will be summoned, boards will
meet, and like normal, problems will be solved.
For additional information you may want to visit
Atlanta Year 2000 Users Group,
and the Microsoft Year 2000 Resource center at
www.microsoft.com/year2000/
Answer provided by Roger Arrick.
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The Five Steps to Data Acquisition
STEP 1 - IDENTIFY YOUR I/O SIGNAL TYPES
When selecting the components for your data acquisition system, you must
first identify the types of sensors and I/O signal types you are using.
Typical I/O types for PC or VXI-based data acquisition systems include:
ANALOG INPUT, ANALOG OUTPUT, DIGITAL INPUT/OUTPUT, TIMING INPUT/OUTPUT.
STEP 2 - CHOOSE A SIGNAL CONDITIONING METHOD
Many types of sensors and signals must be conditioned before connecting
them to a data acquisition device. Use signal conditioning hardware
for: APLIFICATION, ISOLATION, FILTERING, EXCITATION, MULTIPLEXING FOR
HIGHER CHANNEL COUNT.
STEP 3 - SELECT THE APPROPRIATE DATA ACQUISITION I/O DEVICE
Criteria, such as accuracy, acquisition rates, number of channels,
flexibility, reliability, expandability, ruggedness, and computer
platform are used to determine the best data acquisition device for your
application.
STEP 4 - CHOOSE THE APPROPRIATE CABLES FOR YOUR BOARD AND SIGNAL
CONDITIONING ACCESSORIES
Cables connect your data acquisition board to your signal conditioning
accessory or I/O connector block: SHIELDED OR RIBBON CABLE.
STEP 5 - SELECT YOUR SOFTWARE PROGRAMMING METHOD
Two of the three data acquisition solution components are the driver and
application software: DRIVER SOFTWARE, DEVELOPMENT ENVIRONMENTS AND
LANGUAGES.
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Collecting data from an IP address (Ethernet or Internet) directly into Access, Excel, etc.
To collect data from an IP address directly into Windows applications (such as Excel or Access) you can write a custom
application to communicate with the IP address. Because of the popularity of the Internet there are several inexpensive
"programmer toolkits" that make it easy to add support for TCP/IP to any Windows application. If you are a hard core Windows
programmer, you do not even need any tools; you can simply make API calls to the WinSock DLLs that come with Windows. You just
need the specs for the API which are readily available on Microsoft's web site (http://www.microsoft.com). If you are a Visual
Basic programmer, the Pro Edition of VB5 comes with an ActiveX control called the "MSWinSck.OCX" that makes it easy to add TCP/IP
support to VB programs.
If you are not a programmer TAL Tech makes a product called TCPWedge that allows you to collect data from practically any device
on a TCP/IP network directly into any 32 bit Windows program including Excel, Access, etc. TCPWedge takes data from IP addresses,
on any TCP/IP network, parses filters and formats the data and makes it available via DDE to other applications. It can also
fully control devices over TCP/IP networks (Ethernet or Internet). It can support communications with up to 10,000 IP addresses
from within Excel, Access and any DDE supporting Windows applications. For more information please visit http://www.taltech.com.
Answers provided by Susan Rogers
at TAL Technologies
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Making data from my RS232 device available at an IP address on a TCP/IP network
There are "network protocol converters" available that will convert RS232 or RS485 serial data to TCP/IP network data. These
protocol converters - also called terminal servers - make it possible to connect practically any device directly to any network.
For example, you could attach RS232 device to an RS232 to TCP/IP converter and then connect the converter directly to a TCP/IP
network and make it possible for any computer on the entire network to receive data from the RS232 device. Companies with RS232
to Ethernet converters include Lantronix (www.lantronix.com, model MSS1) and Z-World (www.zworld.com, EM1000).
The same functionality can be acheived with TCP/com software, from TALtech Inc, and any Windows PC. TCP/com makes data
from any RS232 port (up to 16 ports) available at IP addresses. A free down-loadable version of TCP/com is available on the Free
Software page on TALtech's web site at www.taltech.com.
Answers provided by Susan Rogers
at TAL Technologies
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