Re: [foxboro] Workstation Integrators

Darren,

When working with the AW-Integrators it is necessary to program to =
maximize the robustness of the I/A to PLC interface, but this is easily =
accomplished.

For example, pulse discrete outputs rather than relying upon sustained =
contacts for start/stop or other discrete command bits.

Any analog outputs set in the PLC will automatically hold the last value =
if communication stops.  You could implement a "heartbeat" such as =
flipping an integer between 1 and -1 that you can monitor with a timer =
if you need to implement any fancier failsafe logic in the PLC if I/A =
communication is lost.  Use of the DCI blocks (ROUT, BOUT, PLSOUT, =
PAKOUT,etc..) will initialize by reading back from the PLC address then =
perform by exceptions writes.  Actually all outputs are write by =
exception with the way that the read/write features of the ECB65s work.

Most importantly, always keep in mind how the AW-Int works; it is able =
to read a block of addresses at a time, but only is able to write a =
single address at a time.  Phasing of outputs is necessary if you have a =
lot of fast changing analog values.  Just setpoints is not a problem.

Also, if you are doing control, make sure all devices to which you are =
communicating are Ethernet PLCs.  In a given BPC, the =
control/communication that is performed is a function of the slowest =
communication to any device.  If you are dealing with DH+ PLCs through a =
PI or CL gateway, your overall throughput will be greatly reduced.=20

At General Mills we almost exclusively use AW51-Integrators to provide =
gateway functionality to AB PLCs.  With only a few exceptions on small =
I/A systems, the AW functions are not utilized with only Integrator =
functionality exclusively being performed.  KVM switches allow this =
machines to normally function as "lights out" machines.

Good Luck,

John Metsker
General Mills, Inc=20

=20
-----Original Message-----
From: Darren Edwards [mailto:darrenedwards626@xxxxxxxxxxx]
Sent: Friday, July 04, 2003 12:25 PM
To: foxboro@xxxxxxxxxxxxx
Subject: [foxboro] Workstation Integrators


Hello:

We own an application workstation integrator used to communicate to a =
PLC-5.=20
  At this time we are using the integrator for data indication only. =20
However, it is desirous at our plant to be able to write commands and=20
operator actions to the PLC-5 from the workstation integrator as well.  =
I am=20
concerned, however, about what happens should the integrator fail or =
need to=20
be rebooted/shutdown for whatever reason.  I do not see in any of the =
ECBs=20
or station blocks any references to failsafe configurations.  Nor do I =
find=20
anything in the documentation that describes what happens to outputs =
when=20
the workstation integrator is shutdown, rebooted, or fails, or goes =
offline=20
from the PLC for any reason.  Does anybody know?

Thanks,

DE

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