Issue
Input alarms in a 7797-15
Environment
I/NET Seven Site
Cause
If a 7797-15 running revisions 1.01 of the binary file has alarming configured on an input point the alarm text will be sent to the message window in AMT every time the point is scanned. This can cause an enormous load on your controller LAN as well as flood your message window making it unusable depending on the number of input points being used.
Resolution
If a 7797-15 running revisions 1.01 of the binary file has alarming configured on an input point the alarm text will be sent to the message window in AMT every time the point is scanned. This can cause an enormous load on your controller LAN as well as flood your message window making it unusable depending on the number of input points being used.
The only current work around is to turn off the message masking and alarm priority for the input point that has the Modbus address associated with it. Then create a secondary point that has the alarming configured and use a P0 calculation to transfer the value. Any event definitions, trend sampling, or other controller functions can still operate on the original input point.
These steps are not necessary for output points since they can be set as internal points and still communicate their values to the Modbus network while the inputs must be external to function.