Re: [foxboro] Modbus FBM, was "Back to forcing an ABSCAN to

     Marcel,
     
     
     *************************************************************
     
     Smaller....OK. Point?
     
     Cheaper....OK. How much?
     
     Faster(etc)OK. So can/is Modbus Plus (1.5MB/s).. but that got canxed.
     
     Many manufacturers are now moving away from the RS232 and RS485 serial 
     links as standard features, and you have to buy a additional comm card 
     to handle this.  There went your price reduction, you just had to 
     spend the money somewhere else.
     
     I understand that the new FBM is better than the old integrator(that's 
     fine and good).. but you can only use it with CP60's which kills it's 
     usefulness. (Saying I have CP40B's and need to integrate Modbus.) Now 
     one has to buy a CP60???? No price break there.
     
     To the point... What is and has been needed for some time now is a 
     "Integrator" or FBM that works with ANY AND ALL CP combinations that 
     talks Modbus over TCP/IP!!!
     
     Regards,
     
     ______________________________ Reply Separator 
     _________________________________
     Subject: [foxboro] Modbus FBM, was "Back to forcing an ABSCAN to writ
     Author:  <foxboro@xxxxxxxxxxxxx> at INTERNET-MAIL
     Date:    12/11/02 11:44 AM
     
     
     
     Hi,
     
     > I thought one of the new Modbus FBM's was Modbus/TCPIP..=20 > which 
     is still "serial" but at a greater throughput?=20
     
No, it supports serial links (RS232 and RS485) with up to 115kBit/s as = 
far
as I know.
     
> If not.. the ONLY advantage would be the flexability of=20 
> locations that the device could be installed,=20
     
No, it's much smaller than an integrator 30, cheaper, faster and = 
supports
direct transmission of floating point values in a 4-Byte format = 
(compatible
to the Triconex Modbus implementation), so that no conversion loss 
(float-integer-float) is existing anymore.
     
That's cool. ;-)
     
Best regards -
     
Marcel Sieling
Systems Technologies
     
Invensys Systems GmbH
Heerdter Lohweg 53 - 55
40549 Duesseldorf
Germany
Tel.:  +49 (0)30-267-15542
Tel.:  +49 (0)211 5966-171
Fax:  +49-(0)172-50-2673077
Mobile:  +49-(0)172-2673077
Email: <mailto:msieling@xxxxxxxxxxx>=20 
Homepage: <http://www.foxboro-deutschland.de>=20
Visit my private (german) homepage: <http://www.powerslider.de>=20
     
     
     
> -----Urspr=FCngliche Nachricht-----
> Von: Daren Bishop [mailto:dbisho@xxxxxxxxxxxx] 
> Gesendet: Dienstag, 10. Dezember 2002 19:30
> An: foxboro@xxxxxxxxxxxxx
> Betreff: [foxboro] Re[2]: Back to forcing an ABSCAN to write, etc=20 
>=20
>=20
>=20
>      Alex,
>     =20
> I thought one of the new Modbus FBM's was Modbus/TCPIP..=20 
> which is still "serial"
> but at a greater throughput?=20
>=20
> If not.. the ONLY advantage would be the flexability of=20 
> locations that the=20
> device could be installed, and all we have is the old=20 
> "Mountain and Mohammed"=20
> scnenario! In other words.. if you don't move forward, it's a=20 
> waste of time and=20
> money. Just another device that doesn't improve performance. 
>=20
> Hopefully for David's sake the AB Integrator FBM will be=20 
> ethernet or DH+ direct.
>=20
>=20
>=20
> ______________________________ Reply Separator=20 
> _________________________________
> Subject: Re: [foxboro] Back to forcing an ABSCAN to write, etc=20 
> Author:  <foxboro@xxxxxxxxxxxxx> at INTERNET-MAIL
> Date:    12/10/02 1:00 PM
>=20
>=20
>     =20
> Well, there's a Modbus FBM coming shortly for CP-60s under=20 
> V6.5. Still it is=20
> only serial and only Modbus.
>     =20
>     =20
> FBMs for other PLCs and physical layers are in the mill, but ... 
>     =20
>     =20
> Regards,
>     =20
> Alex Johnson
> Invensys
> 10707 Haddington
> Houston, TX 77063
> 713.722.2859 (office)
> 713.722.2700 (switchboard)
> 713.932.0222 (fax)
> ajohnson@xxxxxxxxxxx <mailto:ajohnson@xxxxxxxxxxx>=20 
> For the latest information on ArchestrA, go to=20
> www.invensys.com/Archestra.html
> <http://www.invensys.com/divisions/Archestra.html> . 
>     =20
>     =20
>         -----Original Message-----
>         From:        David Johnson [SMTP:DRJohn@xxxxxxxxxx]=20 
>         Sent:        Tuesday, December 10, 2002 11:43 AM=20
>         To:        foxboro@xxxxxxxxxxxxx
>         Subject:        [foxboro] Back to forcing an ABSCAN=20 
> to write, etc
>     =20
>     =20
>     =20
>     =20
>     =20
>         If there is not a way to force a write of the data=20 
> table in event
> driven=20
>         mode, there should be!
>     =20
>         I can save a tremendous amount of my serial bandwidth=20 
> between I/A
> and the=20
>         KF2 if I only write values to the PLC when they=20 
> change.  I may have
> a set=20
>         of timer values that change once a week or less.  The=20 
> longest period
> listed=20
>         in the book is 1024 seconds.  That would be OK in a=20 
> polled situation
> except=20
>         if the operator changes a setpoint from an I/A screen=20 
> it might take
> more=20
>         than 16 minutes for the change to be reflected in the=20 
> system.  Not
> good.
>     =20
>         So we go look at event driven mode.  Values are=20 
> written to the PLC
> only if=20
>         a change is made to the input side of the data.  Changes are 
> transferred to=20
>         the PLC at the time that the operator makes the=20 
> changes.  Very good.
> BUT,=20
>         suppose the PLC reboots, or fails in some other way=20 
> that changes our
>     =20
>         values.  Unless we change the input side of the=20 
> block, no write will
>     =20
>         occur.  So what we want to do is check a heartbeat=20 
> signal and when=20
>         communication resumes after any absence force a write=20 
> of all the
> data in=20
>         the event driven tables.  Then everything will be=20 
> synced up.  I
> can't find=20
>         a mechanism to do this.
>     =20
>         I suppose one could code a method that would=20 
>         a)read the PLC outputs back to I/A
>         b) compare these to the values of the inputs that we think = 
I/A
> should write
>         c) if there is a difference
>             1) change the input value (to what is in the PLC,=20 
> to be most
> bumpless)
>             2) change the value back to the correct value 
>     =20
>         This seems to be way too much work for a problem this simple. 
>     =20
>         Assuming there is not a good way to force a write, what are = 
my
> options?
>     =20
>         RANT MODE ON
>         I HATE serial communications to PLCs! PLEASE get an=20 
> FBM or CP based=20
>         ethernet solution out soon!  And yes I know about=20 
> integrator 50s and
> 70s,=20
>         and yes Alex, I saw some promising things in Orlando,=20 
> but I NEED an
> AB=20
>         integrator FBM NOW!
>         RANT MODE OFF
>     =20
>         Thanks,
>     =20
>         David
>     =20
>     =20
>     =20
>     =20
>     =20
>     =20
>     =20
>     =20
> ______________________________________________________________ 
> _________
>         This mailing list is neither sponsored nor endorsed=20 
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> Process
>         Systems (formerly The Foxboro Company). Use the info=20 
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> ______________________________________________________________ 
> _________=20
> This mailing list is neither sponsored nor endorsed by=20 
> Invensys Process=20
> Systems (formerly The Foxboro Company). Use the info you=20 
> obtain here at=20
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This mailing list is neither sponsored nor endorsed by Invensys Process 
Systems (formerly The Foxboro Company). Use the info you obtain here at 
your own risks. Read http://www.thecassandraproject.org/disclaimer.html 
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_______________________________________________________________________ 
This mailing list is neither sponsored nor endorsed by Invensys Process 
Systems (formerly The Foxboro Company). Use the info you obtain here at 
your own risks. Read http://www.thecassandraproject.org/disclaimer.html
     
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