Re: [foxboro] AB30 TO FBM231
- From: Corey R Clingo <corey.clingo@xxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Fri, 4 May 2007 14:33:56 -0500
Hmm...I had heard that the FBM23x ran an embedded Windows CE OS. Maybe
that whole Windows metaphor ("I am Bill Gates, I am smarter than you, you
don't need to tweak these knobs" - except for when it breaks, and you do
need to tweak them 'cause ol' Bill is screening his calls) is carrying
over. Say it ain't so, Invensys!
I really like the FBM224. It's sole weakness is lack of a fully-redundant
configuration. If they had one for A-B I would de-integrate my Int30s
from my system faster than you can say "ABSCAN". I hope Foxboro doesn't
regress with the FBM23x series.
Corey Clingo
BASF Corporation
"Pat Martens" <fox@xxxxxxxxxxxxxxx>
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05/03/2007 03:31 PM
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Re: [foxboro] AB30 TO FBM231
Ricky,
Roger was one step ahead but I'll post my piece anyhow.
We are currently doing a project which involves 6 FBM231 Modbus links.
(2 Honeywell FSC systems, 4 Siemens PLC systems)
So far we only did an initial test to see if we could get the FBM231 to
work. Before anything, make sure the switches on the termination boards
are
set correctly! (not completely identical to the ones for the COM30
termination boards). The examples in the documentation are worth trying!
I installed a Modbus protocol analyser in parallel (so, read only but both
transmit and receive) to see what was actually happening.
These were my initial findings:
As you might have read in some previous articles in this group there are
some significant differences between handling Modbus through COM30
integrators (I believe very similar to AB30 gateways) and FBM231.
These differences might or might not cause you problems but if they do,
you
will most likely find out only the hard way.
The documentation lacks (IMHO) a sort of comparison table which pinpoints
the differences between MDSCAN block type links, FBM224 type links and
FBM23x type links. This could prevent unpleasant surprises for anybody
using
the FBM23x series modules.
Regarding your question on MCIN/PAKIN, MCOUT, PAKOUT:
A one-on-one replacement will not be possible without some
reconfiguration.
Depending on your CIO complexity you could used icc scripting to do the
job
for you which should make it a reasonable simple task.
We are using FoxCAE to generate all our CIO configurations and had to
create
new typicals.
In our case we could replace the MCIN blocks with PAKIN blocks without any
problems.
We do not use MCOUT but my guess is that the PAKOUT can replace it.
If you use AIN and you want to keep these (in our case we can't do
without;
alarming, display connections etc.) you will have to build a RIN (or IIN)
to
feed the AIN.MEAS.
The RIN block SCI offers you higher flexibility as compared to the AIN SCI
(keep in mind that the AIN SCI's are different in a COM30 module compare
to
a CP!)
So where we used to have say 50 AIN's we will now need another 50 extra
RIN's to feed the AIN's.
The same is true for AOUT blocks (you will need a ROUT (or IOUT).
If you use MAIN then that's to bad, there is no substitute in FBM231!
The FBM231 offers you far less control over the Modbus queries; The
queries
are automatically derived from the RIN's, IIN's, PAKIN's etc.
(Example: define one RIN reading register 40001 and a second RIN reading
register 40020, the resulting query will be to read the full 20 registers
starting from 40001. If your source device does not have a problem with
this
then that's ok. I know however that we have some applications which are
now
implemented with the FBM224 which we could not do with the FBM230/231.
With MDSCAN blocks you could define the exact Modbus queries and do things
like scanning certain modbus registers faster then others. As far as I
know
the FBM231 allows only one overall scan-rate which you define with the
device configurator.
On the positive side (yes, I think there are currently more con's then
pro's); lot's of options to do bit/byte swapping, signed/unsigned etc.
which
eliminates, for some more 'exotic' applications, the need of CALC or IND
blocks to put things right.
However, if your Modbus link is 'straight forward' then the FBM231 should
cause you to much headaches
Kind regards and success with your AB30 replacements!
Patrick Martens
Process Automation specialist
Total Raff. Ned. N.V.
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