This sampling technique continues until all available

expander channels (16 x number of Expander mod

ules) have been scanned, at which time the sequence

starts over.  The number of analog scans required to

include sampling of all expander channels is equal to

the total number of Expander modules x 16 (16 chan

nels per Expander module) in the system.

With no Expander modules present, each base con

verter channel is updated once every 2.4 milliseconds.

With one or more Expander modules present, this

update time increases to 2.8 milliseconds.

Each expander channel is updated every 2.8 x N ms

(where N = total number of Expander channels pres

ent).  Note that the scan sequence is free running and

it cannot be synchronized with any external event.

Also note that all inputs of an Expander module will be

scanned even if they are not being used.