Data Mapping Principles; Default Data Organization; Data In Monitoring Direction; One-Bit Data Mapping - ABB Relion 620 Series Protocol Manual

1MRS757645 B
3.4.3
3.4.3.1
3.4.3.2
3.4.3.3
620 series
Communication Protocol Manual
• The Modbus fault record gives a summary of the captured max-min values and
protection stages starting and possibly tripping during a fault.
• The addressing of the application data in the documentation and tools follows the
so-called Modbus-PLC addressing principle, where the base address 1 is used.
The application data addressing in this IED spans between 1 and 9999.
• The Modbus memory-mapped data in the monitoring direction can additionally
be reassembled into user-definable registers or bits in a specific UDR memory
area. The data can then be scanned also from this area.

Data mapping principles

Modbus data is organized sequentially. This is the most efficient organization method
since the master normally scans the Modbus data in blocks.

Default data organization

The available Modbus data in the IED can be mapped to a Modbus location. Whether
the available data is mapped or not, the data can be taken into use in the Modbus user-
definable area.
A Modbus point that has no premapping does not cause any burden on the IED until
it is taken into use. The Modbus points that are premapped are constantly cached from
the IED application by the stack, regardless of whether the data is read or not.

Data in monitoring direction

All data in the monitoring direction is available through the 3X and 4X memory
areas.This includes the digital indication data which is also readable in the 1X and 0X
areas.
All register structures are located in the 4X area. The address locations of register
structures are similar in all IEDs in this product series.
The Modbus data may contain empty bits or registers within the sequential data areas.
These bits and registers are intended for possible future expansion. Reading this data
does not result in any Mobdus exception response. The value in these bits or registers
is always zero.

One-bit data mapping

All one-bit data in the IED is readable either from the 0X or 1X memory area. The
Modbus bit point addresses are similar regardless of the memory area. In addition, the
same one-bit data can also be read either from the 3X or the 4X area. In this case, the
bit values are packed into 16-bit 3X and 4X registers. The bit locations follow a pattern
similar to the 0X and 1X locations.
If a one-bit value is located in the 0X or 1X bit address 2893, the same bit value can
also be found in the 3X or 4X register 180 (2893 DIV 16) at bit 13 (2893 MOD 16).
Vendor-specific implementation
Section 3
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