Re: [foxboro] FXBAIS system loading

Jack you are correct:
PI fxbais only uses FoxAPI, AIM*API is not required.
When the pi interface is installed, scan classes are created by the
interface startup script;
 fxbais.sh for UNIX, fxbais.bat for WinDoze prior to 8.2, and
go_FXBAIS.ksh for WinDoze 8.2 and later =20
These scan classes are programmed on a per point level by the PI system
admin (Each point needs to have a scan class selected in the Location4
parameter)
The Location2 defines the data lists;
(Recommended practice is that each list is no larger than 255 points and
targets only one station.  Separate lists are also required for read and
write points)
One thing that can whack the whole works though - the interface is
capable of UNBUFFERED reads, can you say OUCH.  This is done by setting
location2 value to 0. =20

So the moral of the story:
1) define and apply your scan classes appropriately
2) manage PI lists - target only on station, and separate read and write
points
3) NEVER use UNBUFFERED points

In my case this is easy, since I am the PI administrator as well as the
Control System Engineer. =20
I have found the PI fxbais interface to be extremely reliable (over 10
years on Unix, and working on the 2nd year of WinDoze)

Just my 2 cents to the party

Sean Meltvedt
Process Control Systems Engineer
Flint Hills Resources Alaska LLC
(907) 488-5170


*************************

-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Jack.Easley@xxxxxxxxxxxx
Sent: Tuesday, June 24, 2008 11:39 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] FXBAIS vs PI OPC Interface

Yes, PI fxbais can be setup to be read-only. Sadly, in our case it is
not. So use of PI read-only from the MESH with a good Firewall is
relatively secure.

However, even if PI access is set up read-only, you should not forget
the matter of additional loading of your control system when PI tags are
added by the PI administrator. We experienced problems with this when at
Version 6.12 NODEBUS with loaded CP30/40s and Integrator 30s.

I don't think AIM is involved with the PI fxbais Interface, only FoxAPI.

Jack Easley

-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Johnson, Alex P (IPS)
Sent: Tuesday, June 24, 2008 1:05 PM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] FXBAIS vs PI OPC Interface

Re: Read-only and FoxAPI (and AIM*API for that matter)

It is possible to configure read-only access using FoxAPI. This
configuration is done in the /opt/fox/ais/bin/an_init.tcp file on the
machine running the netFoxAPI Server (an_server).

If this is set, it does not matter what PI is configured to do, the data
will not be written.

For AIM*API, the file is /opt/aim/bin/an_init.tcp.

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