Re: [foxboro] FCP's vs. ZCP selection on new projects

  • From: <tom.vandewater@xxxxxxxxxxxxxx>
  • To: <foxboro@xxxxxxxxxxxxx>
  • Date: Tue, 14 Aug 2007 12:44:10 -0400

Alex,
        I understand the reasons for your response and have contacted
Matt off list with my questions and requests.  From my observation,
several people on the list would like to see ZCP functionality in the
FCP form factor.  That has spurred Foxboro to try to expand the number
of FBM's an FCP can host.  I'm skeptical of whether an FCP would be very
useable when hosting 128 FBM's, even across a 2MB/s RS485 bus.  I am
leery of sinking a lot of eggs in the FCP basket.  I had a similar
feeling about the Micro IA offering that was supposed to be a low cost
control alternative, much like the FCP.  We avoided them like the plague
and now I am forever thankful.

Tom

-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Johnson, Alex P (IPS)
Sent: Tuesday, August 14, 2007 11:42 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] FCP's vs. ZCP selection on new projects

The 128 FBM limit is the published specification. =3D


I'm not going to make any comments on whether or not one can violation
our specification without consequences because I'm not that crazy. :)

As far as changing the limit is concerned, you'd have to take that up
with Marketing - Matt DeAthos and Betty-Naylor.

I hope this helps and I do understand the issue.

Regards,

Alex Johnson
Invensys Systems, Inc.
10900 Equity Drive
Houston, TX 77041
713.329.8472 (voice)
713.329.1700 (fax)
713.329.1600 (switchboard)
alex.johnson@xxxxxxxxxxxxxxxx


-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of tom.vandewater@xxxxxxxxxxxxxx
Sent: Tuesday, August 14, 2007 11:17 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] FCP's vs. ZCP selection on new projects

        Below is an actual case study based on our experience with
CP-60's.  We initially used multiple FBI10E's, (10MB E-Net to 268KBS
RS-485), to communicate with our 100 series I/O.  We limited each FBI10E
to host no more than 24 FBM's.  We were able to communicate with 120
FBM's and the Fieldbus scan as a percentage of Total Control Cycle was
only 32 percent, or about .25 percent loading per attached FBM.

Being good customers, we complained about the cost of all the FBI10E's
and the clumsiness of the thin net to connect them to the CP-60
fieldbus.

        Foxboro responded and said we could save a lot of money and thin
net if we used one set of DCM10E's, (10MB E-Net to 268KBS RS-485), and
connected all of our pre-existing old style FBI segments to it using the
same Belden twin-ax that was in place from previous CP10's, 30's, and
40's.  We said that sounds great and we installed it that way.  We were
able to communicate with 59 FBM's and the Fieldbus scan as a percentage
of Total Control Cycle was 55 percent, or about 1.00 percent loading per
attached FBM.  In addition, we had huge numbers of fieldbus
communication errors on the CP using the DCM in this arrangement.

Alex said in his note on this subject:
"a lot of the I/O performance of the ZCP comes from a strong
co-processor in the box plus the parallelism of the FCMs."

I am sure he is correct.  As such there should be no expectation that a
FCP using today's design will ever be a suitable replacement to
communicate with as much I/O as a ZCP.  I expect that trying to
communicate with 120 FBM's via a single 2MB/s RS485 fieldbus used by the
FCP will be about "ONE FOURTH" as efficient as using distributed FCM100
segments communicating at 100MB/s to a ZCP so everyone should be aware
of that very real limitation.

Corey Clingo summed it up best for me when he said:
"Like Tom, I like the ZCP's capabilities and the FCP's form factor."

Here are more specific reasons for my request: =3D3D20
        Using the 200 series baseplates and I/O form factor, (less
depth), we have been able to achieve double sided, (back-to-back),
mounting in the same 19" rack.  That allows us to share power
distribution and fiber communication infrastructure over 8 baseplates
instead of 4 1x8's like we used in the past for 100 series I/O.  With an
FCP form factor we could mount the CP's in the same rack space.  The
depth of the 1x8's used for the ZCP's takes up the entire space,
(front-to-back), in a standard 19" rack.
        In addition, our processes are large enough to require 80 to 150
FBM's.  This is too much for an FCP, but we now see that a ZCP could
easily handle that kind of load.  One of our ZCP's communicates with 82
200 series FBM's and uses 20 percent for field bus scan.  Again, about
0.25 percent loading per attached FBM. There is an advantage for us to
be able to fit each process in its own CP.  Peer-to-peer becomes more
undesirable as we increase our sequence automation.  Change deltas and
timing for values being passed between CP's is an issue with
peer-to-peer but if all control for a process is in one CP there is no
need to use object manager resources to get and set the values and a
more timely and robust execution is achieved.  That is my reason for
wanting Foxboro to allow a larger number of FBM's connected to a ZCP
that can clearly handle the additional load.

Questions to Alex or Russ:

Is the 128 FBM limitation a gospel rule or could a user add more than
that to a ZCP today?

If it is a hard and fast rule, how difficult would it be to modify from
Foxboro's perspective to allow a larger number of FBM's?

Thanks again for any feedback,

Tom VandeWater
Control Systems Developer/Analyst
Dow Corning Corporation
Carrollton, KY   USA




-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Boulay, Russ
Sent: Tuesday, August 14, 2007 8:05 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] FCP's vs. ZCP selection on new projects

The FCP270 uses FEM100's to go beyond 32 FBM's
With the FEM100 only one pair is allowed. 4 ports going to 4 basplates
each.
So, FEM100 is trying to do all the work.
So, number per sizing spreadsheet will vary from 64 to 128 FBM's
depending on what your asking the FCP to do.

The ZCP270 can use multiple pairs of FCM100's to split it's fieldbus
load.
32 FBM's per FCM100
Multiple FCM100's drops the I/O load on a ZCP
Thus allowing more FBM's


-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Kinsinger, Matthew R
Sent: Tuesday, August 14, 2007 7:58 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] FCP's vs. ZCP selection on new projects

I took a class at Foxboro last week. We were interested in the new V8
=3D3D3D3D
stuff and learning about IACC so I only took 2001V8. Alan Leslie, the
=3D3D3D3D
person teaching the course, made it very clear the FCP270 now supports
=3D3D3D3D
128x 200 series FBMs and 64 100 series. I notice many of you are still
=3D3D3D3D
focusing on the original 32 then 64 200 series supported. =3D3D3D3D20

With the 128 supported, is the FCP still using FEM's instead of FCM's?
=3D3D3D3D
Is that the limiting difference?


Matt Kinsinger
Process Control Engineer=3D3D3D3D20
PPG Barberton
330-825-1208

-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
=3D3D3D3D
On Behalf Of Corey R Clingo
Sent: Tuesday, August 14, 2007 1:51 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] FCP's vs. ZCP selection on new projects

I've been watching this whole FCP vs. ZCP discussion with some interest.
=3D3D3D3D

It seems to me on the surface that control system vendors today are =
=3D3D
=3D3D3D3D
going=3D3D3D3D20
to a model of more controllers with fewer I/O cards per controller,
I=3D3D3D3D20
presume to "reserve" more power in the controller for advanced =3D3D3D3D
algorithms=3D3D3D3D20
as well as simplify the system architecture (particularly if they
don't=3D3D3D3D20
allow I/O remote from the controller at all).  Of course as you split
=3D3D3D3D
your=3D3D3D3D20
plant amongst more controllers, the amount of peer-to-peer you end
up=3D3D3D3D20
doing probably increases.  I wonder how the industry in general is
=3D3D3D3D
dealing=3D3D3D3D20
with that (besides going to faster networks, of course).

I don't have any CPs right now that have more than 61 FBMs, but if the
=3D3D3D3D
FCP=3D3D3D3D20
is limited to 64, I would likely split a 50+ FBM CP40 up into two FCPs
=3D3D3D3D
if=3D3D3D3D20
I were going to use those, just so I could have a few more spare I/O.
=3D3D3D3D
I'd=3D3D3D3D20
probably end up doing some more P2P though to effect that split.  P2P
=3D3D3D3D
has=3D3D3D3D20
worked well for me in the past, but I use it sparingly.  Is it any
=3D3D3D3D
better=3D3D3D3D20
on the FCP than, say, a CP60?


Like Tom, I like the ZCP's capabilities and the FCP's form factor.


Corey Clingo
BASF Corporation






"Johnson, Alex P \(IPS\)" <alex.johnson@xxxxxxxxxxxxxxxx>=3D3D3D3D20
Sent by: foxboro-bounce@xxxxxxxxxxxxx
08/13/2007 11:11 PM
Please respond to
foxboro@xxxxxxxxxxxxx


To
<foxboro@xxxxxxxxxxxxx>
cc

Subject
Re: [foxboro] FCP's vs. ZCP selection on new projects





I'll give it a try.


Re: I guess the FCP's were initially developed as a lower cost
alternative.
True. They were also expected to serve as a way to enter new markets
once they are self-hosting.


Re: It is my understanding that the the FCP's have the same
horsepower with the exception that they don't have fast =3D3D3D3D3D

Ethernet fieldbus communication.  =3D3D3D3D3D

True enough, but a lot of the I/O performance of the ZCP comes from a
strong co-processor in the box plus the parallelism of the FCMs.


Re: Adding that capability would make the FCP's a lot more flexible and
would make it easier for them to communicate with multiple
distributed
segments of I/O in the same way as the ZCP's
The original plan was to offer three CP270s:

1) Field mounted (FCP) for use in situations where the controller would
be
Field mounted.
2) Z-module (ZCP) form factor to allow the reuse of the cabinets and
=3D3D3D3D3D

power supplies owned by our installed base.
3) Rack mounted (RCP) which was to be - basically - ZCP in a DIN rail
mounted tin can.

We built the first two. I suppose one could argue about the product mix,
but we felt the ZCP was important to the installed base.

Clearly as we look forward to new CP hardware, the mix may change.


Re: PSSs
The specification sheets are correct.


Re: Does Foxboro have plans to release a CP in the FCP form factor that
uses
a Fast Ethernet Fieldbus?
Not in the near term.


Re: Has Foxboro considered increasing the number of FBM's that a ZCP can
communicate with?
It has been stressed test well beyond 128, but we don't see a compelling
reason to increase the published limit on the ZCP. =3D3D3D3D3D


Most new jobs find the FCP to offer a better $ per I/O point ratio.

Moreover, even in the installed base, a large number locations are
interested in using the FCP to free space in their rack room. An FCM
takes the same space as an FCP so unless there is a truly compelling
reason, most folks don't use the ZCP. They remove the old racks and use
the FCP.

Given the above, we've worked to improve the $ per I/O point ratio of
the FCP as being the best short-term approach for our clients.


Regards,

Alex Johnson
Invensys Systems, Inc.
10900 Equity Drive
Houston, TX 77041
713.329.8472 (voice)
713.329.1700 (fax)
713.329.1600 (switchboard)
alex.johnson@xxxxxxxxxxxxxxxx


=3D3D3D3D20
=3D3D3D3D20
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