Because each of {HEAD ~ the function blocks} is typically scheduled to execute so that execution of that block is completed shortly before the block is scheduled to receive a compel data command, the data published in response to {TAIL ~ a compel data command} should be the most recent output data of the function block 
Because each of { HEAD ~ the function blocks } is typically scheduled to execute so that execution of that block is completed shortly before the block is scheduled to receive a compel data command , the data published in response to { TAIL ~ a compel data command } should be the most recent output data of the function block
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH