Rockwell Automation 1403-NDNET DeviceNet Communications Card Installation Instructions - Manual (Page 24)

Publication 1403-IN054A-EN-P - August 2001
1-18 Product Description
Every Scan Polled I/O Messaging
The optimal polling rate for the Every Scan message type is 28 ms. An
Interscan Delay smaller than 28 ms causes the Powermonitor II to
delay the update of its metering information.
Background Polled I/O Messaging
Background Polled I/O Messaging occurs after the specified number
scans by setting the Foreground to Background Poll Ratio. As long as
the total scan time is greater than 28 ms, the Powermonitor II
communicates at its optimal speed.
EXAMPLE
The Interscan Delay is set to 5 ms, and the Foreground to
Background Poll Ratio is set to 5. Therefore, the total scan
time is:
Foreground (5ms + 5ms + 5ms + 5ms + 5ms) +
Background (5ms) - 30ms.