Michel, In a PLB block, I don't believe that the times can be varied by external means. They are hard coded into the PLB logic. A CALC block might be your best bet for something like this. Stan M. Ruth, P.E. Process Control Engineer Huntsman O&O Plant E-mail: stan_ruth@xxxxxxxxxxxx mvandenberg@xxxxxx Sent by: To: foxboro@xxxxxxxxxxxxx foxboro-bounce@fre cc: elists.org Subject: [foxboro] a simple challenge 11/21/2001 02:24 AM Please respond to foxboro Hi list, We are going to replace a local relay / timer driven filter cleaning sequence by "something" in I/A. We therefore need to separately activate 4 solenoids, one after the oth= er, for a variable number of seconds (most likely 2). The interval between activating the solenoids should also be variable. I have already made something with a Calc block that generates seconds = ( 0 to 62) connected to a AIN block. On the four boolean alarm limits I connected the solenoids using a GDEV with the pulse option on. But ther= e must be something more brilliant than this, without the use of a DEP bl= ock. The solenoids will be connected (2?wire) to FBM41C/42C, therefore a PLB= solution is an option. All suggestions are more than welcome. thanks, Michel Michel van den Berg PFW Aroma Chemicals B.V. PO Box 415 3770 AK Barneveld the Netherlands Phone : (31)342 - 407 791 Fax : (31)342 - 407 789 email : mvandenberg@xxxxxx FedEx : Nijverheidsweg 60 3771 ME Barneveld the Netherlands = ___________________________________________________________________ This list is neither sponsored nor endorsed by The Foxboro Company. Use the information obtained here at your own risk. For disclaimer, see http://www.thecassandraproject.org/disclaimer.html#maillist list info: //www.freelists.org/list/foxboro subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave ___________________________________________________________________ This list is neither sponsored nor endorsed by The Foxboro Company. Use the information obtained here at your own risk. For disclaimer, see http://www.thecassandraproject.org/disclaimer.html#maillist list info: //www.freelists.org/list/foxboro subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave