"Part of the issue is the external references - assuming it is outside the CP holding the IND block. If that is the case, each one of those will suspend the block for 1 BPC (minimum) which translates into 1 block period." Alex, If the external references are in the same CP, or compound, does this still hold? Could you make connections to AIN blocks or whatever and then reference those in the HLBL without the time penalty? Corey "Johnson, Alex P (IOM)" <Alex.Johnson@xxxxxxxxxxxx> Sent by: foxboro-bounce@xxxxxxxxxxxxx 03/01/2010 08:58 AM Please respond to foxboro@xxxxxxxxxxxxx To "foxboro@xxxxxxxxxxxxx" <foxboro@xxxxxxxxxxxxx> cc Subject Re: [foxboro] IND question Part of the issue is the external references - assuming it is outside the CP holding the IND block. If that is the case, each one of those will suspend the block for 1 BPC (minimum) which translates into 1 block period. So, at the minimum, your WAIT UNTIL is adding 1 block period delay. Can you bring that value into a RIxxxx parameter? That would eliminate that delay. The same hold true for the external references in the rest of the code. I once had a client call and complain that his safety shutdown logic took to long to run. I asked how is it implemented and how long does it take. He said it is 20 lines of sequence code and it takes 10s to complete. He sent the code with his reply. It was 20 external references in a block with a 0.5 PERIOD. I had to explain that what he saw is normal. The fix? Bring the values in as connections. Does this help? Regards, Alex Johnson Invensys Operations Management 10900 Equity Drive Houston, TX 77041 +1 713 329 8472 (desk) +1 713 329 1600 (operator) +1 713 329 1944 (SSC Fax) +1 713 329 1700 (Central Fax) alex.johnson@xxxxxxxxxxxx (current) alex.johnson@xxxxxxxxxxxxxxxx (good until September 2010) _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave