ControlLogix I/O config (RSL5000)

Hi
In the 'properties' dialog for a 16 way input module, there's a tab where you can enable change of state on->off and off->on for each point.
What does this do? Does it override the RPI? Or does it send data on a change of state AND at the RPI too?
Thanks

What ware the default values, on or off ?

The module will send data to the controller upon the change of state of an enabled point, or when the RPI interval ends, whichever is first.

The defaults are all ON, and on most systems it doesn't really matter because you can set an RPI that's very low (the default is 5 ms for discrete modules) and still not overwhelm the backplane's bandwidth.

If you have an application where you have to cut down on I/O bandwidth, Change-of-State is useful to maintain responsiveness while not transferring all the module data all the time. I think the status data is transferred only at the RPI.

When you're using input timestamping, you usually enable only one point on the card for COS, so that it's change is certain to give you an accurate timestamp. If several points are set to COS and you're using timestamping, the last point to change will overwrite the timestamp value from the module, making it difficult to compare the input times of points on the same module.

I have to ask, what is 'RPI' ? I have presumption, but I like to be sure.

RPI stands for "Requested Packet Interval".

In Rockwell producer/consumer systems like ControlNet, EtherNet/IP, and the Logix backplane, this is the maximum amount of time between productions of data from one device to another.

If you set up an input module for 10 milliseconds RPI, it will report it's data to the controller at least every 10 milliseconds. The "change of state" option available in the Logix backplane allows the module to report it's data whenever an input point changes, but it will still report at the RPI rate too.

RPI-
Requested Packet Interval

YA beat me....

I need to remember to do a refresh before posting.......

Thanks Ken, that was exhaustive explanation !