Rockwell Automation 1769-SDN Compact I/O DeviceNet Scanner Module User Manual - Manual (Page 72)

72 Publication 1769-UM009E-EN-P - August 2009
Chapter 5 Manually Configure the DeviceNet Network
Module Tab
Interscan Delay
This parameter defines the delay time the scanner module uses between scans
of the DeviceNet network. If you have slave devices configured for polled
behavior in the 1769-SDN scanner module scanlist, Interscan Delay (ISD)
defines the amount of time the scanner module waits between DeviceNet I/O
updates.
Increasing the ISD time causes a longer network scan, which adversely affects
overall input-to-output performance. However, the increase allows lower
priority messages to get more network access. These lower priority messages
include those used to do network browsing and configuration
upload/download functions. So, if these network functions are sluggish on
your system, increase the ISD time.