Re: [foxboro] IND Block error

On my similar application, I used a block exception handler with a dummy 
wait in it.  We are throwing the display up on multiple WPs so I didn't 
bother retrying on the unresponsive WPs, but it does keep the IND block 
from going to manual:

BLOCK_EXCEPTION TO_SYS_ERROR
STATEMENTS
    { Dummy code to make sequence continue at next WP if one
      of them is offline }
    WAIT 1.0;
ENDEXCEPTION


If you want to trap other kinds of exceptions, you may have to use more 
intricate code, or this may not even work.  But my application is simple, 
and this was a perfect way to step over dead WPs.


Corey Clingo
BASF Corp.





Ron Schafer <rschafer@xxxxxxxxxxxxxxxxxxxxxx> 
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11/06/2009 12:45 PM
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Subject
[foxboro] IND Block error






Ok, I was surprised by a block error yesterday on a ind block (46IND5325). 
Basically the code loops through a sequence of checks and events and 
during one check it will send the following command IF a certain condition 
exists.
:46AW03DMCMD := "dmcmd /OPT/MENUS/46AREA/PAPER_MACHINE/BROKE.FDF";

Normally the command will pull up a display (BROKE.FDF) on Foxview 46AW03. 
Here is where the catch comes into play. The station(46AW03) had a 
hardware problem and was not powered up or on the mesh and caused the seq 
block to go to manual. Since the MA parameter is set to "MA = 
:46IND5325.MA.1" The block would kick back into auto and fail again, 
etc....

So my question to all is how would you handle the block so it doesn't fail 
just because a workstation is not alive? Error handling routine? IF/Then 
check? Some other means? I was very surprised that the block knew the 
station was not reachable and the ind block went to manual!
Ronald G. Schafer
Distributed Controls System Administrator
White Birch Paper Company
Bear Island L.L.C. Division
10026 Old Ridge Road
Ashland VA, 23005
Phone 804-227-4034
Fax 804-227-4052
Email: rschafer@xxxxxxxxxxxxxxxxxxxxxx<
mailto:rschafer@xxxxxxxxxxxxxxxxxxxxxx>


 



 
 
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