Re: [foxboro] Topic for discussion - CP Workfile Recovery

Thanks for this, Alex.
 
Do you have any ideas about printers going on and off line continually with an 
AW70?  We are getting nutcracker messages in the NT event log.  I am convinced 
we need a quick fix or something...
 
Rose A.
"Johnson, Alex (Foxboro)" <ajohnson@xxxxxxxxxxx> wrote:
It must be the time of year, the topic of how to properly back up a CP and
how to recover from the loss of the hard drive on the hosting AW has come up
several times and I'm getting tired of doing this one at a time. So, here
are my thoughts for all to ponder.

This is really a case where free advice is worth what you pay for it.
Remember, this does not replace the standard company policy of:

1) SAVE ALL
2) Failure
3) INITIALIZE
4) Reboot
5) LOAD ALL

However, even the company standard procedure does not address everything,
e.g., #include files. So, be sure you keep those up to date somewhere off
platform.

So, with all of the expected caveats about free advice and standard
documented procedures, read on.


I have the general outline of a procedure, but it is NOT for the faint of
heart. There are at least a few difficulties and probably more. The ones
that I can think of are:

1) Recovery of Sequence Code Source and Ladder Logic source is not going to
happen, you must have up to date backups of this code. Basically, my advice
is, "Make a SAVE ALL every time you recompile a Sequence Block or a PLB
block." Also, if you use #includes you need to back those up, they won't be
on the SAVE ALL.
2) Block Order recovery can be awkward. You can use the order shown by the
CP in the FoxSelect or Select window as the master and make the workfile
match it - see below for what I'm talking about.
3) dbvu does not like dumping out the parameters of CPs that have certain
ECBs in them. I'm talking about the -t option (at least the last time I
tried it on a CP60). This can make life tougher.

General words of advice:
1) Get help from Field Service! I can't stress this enough. There are guys
who have had the (mis)fortune of doing this more than once. You probably
have not.
2) Understand what the relationship is between CSA, work files, checkpoint
files, CP RAM, and the Sequence Block and Ladder Logic source code.
3) In the future, be dead certain to make SAVE ALLs after all changes to
Sequence (IND, EXC, DEP) or PLB blocks. This preserves your source code.
Regular Save Alls will minimize the work, but will not eliminate the need
for this procedure.
4) If you use #include statements in your sequence code, you'd better back
those files up! SAVE ALLs don't preserve them.
5) Save Alls can be automated using scripts that can be found on the
Cassandra Web Site. While that will not totally remove the need for SAVE
ALLs after alterations of Sequence and Ladder Logic code, it will help.

Here is the general gist of the procedure.

1) Setup a duplicate system off line. It should contain at least an AW/AP
with the latest backup tape for the CP host and a CP of the same type with
the same letterbug.
2) Boot the off-line system
3) Determine which compounds/blocks have been added / deleted between the
two CPs. You can use a variety of tools to get this information. 
a. Workfile contents
i. The print options of the ICC and ICC Driver Task can document the
workfile
ii. The refs toolkit - on the Cassandra site - can document workfiles
b. CSA
i. The CSA tools (see the attached file csa_util.doc) can be used to see
what CSA thinks is there.
c. CP's Running Database
i. /opt/fox/bin/tools/dbvu - can be used to examine a checkpoint file and
pick out compound and block names.
ii. FoxSelect can be used to determine what the CP actually has in it (same
info as dbvu)
d. Block Order - Use Select or FoxSelect to see the order of the blocks as
known to the CP.
e. Source Code Files - are a problem because they are on the host and not in
the CP. There is no way to to ensure that you actually have the latest
source code for the Sequence Blocks and PLB blocks.
4) Use the off-line system to build a correct CP image. That is, one
a. That has the correct set of compounds and blocks. This is a pain.
b. That has the right block order
c. That has up to date Sequence and Ladder Logic blocks
i. The correct Sequence Code and Ladder Logic files 
ii. The correct #include files.
iii. Recompiled source
5) Once you have an up to date CP configuration in the off-line machine, you
need to move it to the main machine.
a. Make a backup of the critical files
i. cd /opt/fox/ciocfg
ii. tar cvf .tar 
where is something like CP0001
is the name of a compound in the CP that contains Sequence or PLB
blocks. 
b. Move the tar file () to the on-line host and put it in
/opt/fox/ciocfg
c. Extract the files (tar xvf .tar)
d. Start the ICC and perform an upload from the CP
6) Use the CSA utilities to fix the CSA database if necessary.

Other techniques are possible given different starting points. Some of you
may have everything back documented with FoxCAE for example, but they all
boil down to this.


Regards,

Alex Johnson
Invensys Systems, Inc.
10707 Haddington
Houston, TX 77043
713.722.2859 (office)
713.722.2700 (switchboard)
713.932.0222 (fax)
ajohnson@xxxxxxxxxxx
For the latest information on ArchestrA, go to
www.invensys.com/Archestra.html.




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