Rockwell Automation 1758-RTU202 DataSite Hardware User Manual - Manual (Page 51)

Publication 1758-UM001D-EN-P - June 2011
Operating the Controller 51
Real-Time Clock
The real-time clock of the DataSite controller provides the time and date
independently for the operating system. The time and date remain correct
during power off. The calendar automatically manages leap years.
Real time clock can be saved into register by reading through the DataSite
function block, [CLOCK_GET]. The values for the data and time date are
stored in single registers as two-digit values.
For example the date and time, 17:32:23, 2004-07-13, would be stored as:
For example the date and time, 00:00:01, 2000-01-01, would be stored as:
Application programs that use the date and time data must ensure that the
rollover from year 99 to year 00 is accounted for in the program.
Modbus Register
Assignment
There are four internal registers in the DataSite controller:
• Coil_Register,
• State_Register,
• Input_Register,
• Hold_Register.
Coil_Register and State_Register are bit registers, every register address of
which is accorded with a binary bit.
Input_Register and Hold_Register are 16-bit registers.
The following table shows the Modbus address range of the controller.
Hour Minute Second Year Month Day
17 32 23 04 7 13
Hour Minute Second Year Month Day
00 00 01 00 01 01
Register name Modbus address Features
Coil_Register 00001-04096 1-bit
State_Register 10001-14096 1-bit
Input_Register 30001-31024 16-bit
Hold_Register 40001-49999 16-bit