[H-GEN] Remote process monitoring & control

[Doug Young]

(Note reply-to: being general at humbug.org.au vs "Doug Young" <dougy at gargoyle.apana.org.au>)

Thanks Michael ..... original intentioin was toi interface a PC with all the
machine PLC's but now always on lookout for simpler and consequently more
reliable ways of doing it. The Dick Smith kits are supposed to have
"opto-isolation" whatever that implies

-----Original Message-----
From: Michael Anthon <mca at tams.com.au>
To: 'general at lists.humbug.org.au' <general at lists.humbug.org.au>
Date: Thursday, July 15, 1999 2:55 PM
Subject: RE: [H-GEN] Remote process monitoring & control


>(Note reply-to: being general at humbug.org.au vs Michael Anthon
<mca at tams.com.au>)
>
>Oh, err.. bleargh.
>
>OK, I misunderstood.  I thought you were going to interface into the
>existing PLC systems to get the info you wanted, not add a complete new I/O
>system to do it for you.  If it is a simple parallel I/O board such as you
>are talking about, reading/writing them is usually as simple as
>reading/writing some part of the I/O space on your PC.  Many, many years
ago
>I used to do this sort of thing with a system called OPTO 22 and Turbo
>Pascal *grin*.
>
>If you are putting this into a commercial factory situation, I would look
>very carefully at the electrical isolation of the system you are using.  A
>lot of the cheaper systems are not well designed which can lead to several
>problems.  The most drastic of these is a total breakdown of your isolation
>during a fault condition (which could be as simple as a surge from a motor
>causing a voltage spike).  This can lead to nasty high voltages being
>applied to parts of you computer that they really should NOT be applied to
>and even into your LAN if the network card is also not well isolated....
>Another potential [1] problem is the injection of HF noise into your
>computer from the I/O circuits (again, usually caused by switching of heavy
>machinery motors and solenoids).  This tends to cause extremely hard to
>duplicate intermittent faults.
>
>This should be the sort of thing that would be pretty easy to do in Linux,
>you could even build a nice web interface to allow you to view the status
>and control things...  I've never done any I/O work in Linux, perhaps
>someone else could tell us how hard this is to do.  Would perl or PHP be
>capable of doing I/O?  That would be nice 8^)
>
>Hehe.. looks like programming in VBA [2] for the last couple of years
hasn't
>dulled my interest in this sort of stuff.
>
>
>Cheers
>
>Michael
>
>[1] Pardon the pun
>[2] Take pity on me
>
>> -----Original Message-----
>> From: Doug Young [mailto:dougy at gargoyle.apana.org.au]
>> Sent: Thursday, 15 July 1999 1:57
>> To: general at lists.humbug.org.au
>> Subject: Re: [H-GEN] Remote process monitoring & control
>>
>>
>> (Note reply-to: being general at humbug.org.au vs "Doug Young"
>> <dougy at gargoyle.apana.org.au>)
>>
>>
>> -----Original Message-----
>> From: Michael Anthon <mca at tams.com.au>
>> To: 'general at lists.humbug.org.au' <general at lists.humbug.org.au>
>> Date: 15 July 1999 10:00
>> Subject: RE: [H-GEN] Remote process monitoring & control
>>
>>
>> >(Note reply-to: being general at humbug.org.au vs Michael Anthon
>> <mca at tams.com.au>)
>> >
>> >This is a pretty broad subject.  There are many, many, many
>> types of PLCs
>> >and factory automation equipment out there.  Unfortunately,
>> because it is a
>> >fairly competitive industry, there was never a defined standard for
>> >inter-communication between these devices.  Each
>> manufacturer tended to
>> come
>> >up with their own protocol.  Some used RS232, some RS422,
>> some optical
>> >fibre, some a parallel interface.. etc etc.
>> >
>> >That said, the Gould MODBUS protocol has become somewhat of
>> an industry
>> >standard and when I was last involved in this sort of thing
>> (about 3-4
>> years
>> >ago) there were moves afoot to produce a standard protocol
>> (I think it was
>> >called FieldBUS or something, F-BUS perhaps).
>> >
>> >At what level do you need to interface to these devices?
>>
>> ummmmmm .... would you re-phrase that in words of less than
>> two syllables ??
>> The situation involves a bunch of (mostly) plastic extrusion
>> moulders with
>> PLC's already and I want to be able to monitor simple
>> functions like has an
>> alarm tripped / is something running or not  etc. There are
>> heaps of Windows
>> boxes around the place including spare 486's that could be switched to
>> whatever flavour of unix, a LAN between the actual factory
>> and the office,
>> and a dialup WAN to another office location. Ideally the
>> status of various
>> machines will be monitored from anywhere with dialup access
>> to the LAN, and
>> hopefully also from the net.
>>
>> If you are going
>> >to have to write serial protocol drivers for them, then I
>> would suggest
>> that
>> >VBA would not be the tool of choice.....
>>
>>
>> OK .... so is there a reasonably straightforward solution ??
>> ..... I notice
>> both Jaycar and Dick Smith have cheap I/O interface kits
>> available that
>> apparently use QBasic programming and which appear to do what I need,
>> however I don't know whether or not I can monitor and control
>> stuff remotely
>> if I use QBasic.
>>
>>
>>
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