Control Data Systems Versa Router 950, User Manual

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Ref.no.: 003274/Revision 2.4 @2019 Control Data Systems Page 110 | 201
1. in an empty edit box, type the parameters in the order and format indicated in the Help form:
start address, word count, EUI64, TSAPID, object ID, attribute ID, index1, index2, method ID, and
status byte type;
2. click Save to add the new register line in the Registers list.
Notes :
1. When mapping the Modbus registers on the ISA100.11a data entities, you must consider the size
of the ISA100.11a attribute and allocate a contiguous chunk of Modbus 16-bit registers in the
Modbus addressing space to hold the entire data entity (plus an additional Modbus register to
hold the auto-generated status, if applicable). When the chunk is bigger than the size of the data
entity, it will be filled with the actual data from the lowest addressed register to the highest, and
from the MSB of each register to the LSB. If the data entity does not entirely fill the last register,
the register will have the data on the MSB, and the LSB will be set to zero.
2. The status byte type for the mapped register can have one of the following three values:
•
0 or missing – if the attribute does not have a status byte; in this case, the ISA100.11a entity
is mapped onto the registers, starting at the address <start_address>.
Example:
169,2,6202030405060C04,2,1,66,0,0,0, 0
In the above holding register line, DEVICE_ATTRIBUTE is 4 bytes data, no data status
byte. When mapping to Modbus registers, it can have the Modbus status byte type set
to 0; 2 words will be needed, as follows:
o
First word: DEVICE_ATTRIBUTE (upper);
o
Second word: DEVICE_ATTRIBUTE (lower).
•
1 – only for standard ISA100.11a data types 65 (process value and status for analog value)
and 66 (process value and status for binary value). In this case, the first byte in the
ISA100.11a attribute is a status byte, so it must be expanded to one Modbus word (the first
one), at the address <start_address>; the rest of the ISA100.11a reading bytes will be
mapped to registers starting from the address <start_address>+1. After the expansion, the
first Modbus word will have 0x00 as the MSB, and the status byte as the LSB.
Example:
140,3,620203040506FC09,2,130,1,0,0,0, 1
In the above input register line, the analog process value is 1 byte data 4 bytes
data. When mapping to Modbus registers, three words will be needed, as follows:
o
First word: 0x00 + data status in PV;
o
Second word: data in PV (upper);