Hardware User Manual Manual

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

Coil_Register 00001-04096 1-bit

State_Register 10001-14096 1-bit

Input_Register 30001-31024 16-bit

Hold_Register 40001-49999 16-bit