Rockwell Automation 1758-RTU202 DataSite Software User Manual FRN 1.2 - Manual (Page 105)

Publication 1758-UM002D-EN-P - October 2010
DataSite Configuration Settings Utility (DS Settings) 105
Value in Registers State
The values in the DI, DO, AI, AO, and PI registers are not saved when the
DataSite controller powers down. When the DataSite controller powers up, the
DI, AI, and PI registers will receive actual values from the input signals, DI,
AI, and PI but the values in the DO, AO, and PI registers will be cleared to
zero.
If you configure some scan blocks or HART blocks, the values in the Master
Registers of all the blocks will remain at the last saved values before
communication failed. So you need to use the relevant function block to check
the communication status to determine whether the value is valid. You can
write a program in DataSite Workbench to read the current communication
status, and then save the status into a Modbus register as an indicator to be
used by other programs.
For the list of function blocks you can use, refer to DataSite Customized
Function Blocks Reference Manual, publication
1758-RM001 .