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DNP 3.0 and MODBUS Data Structures
the slave, the “command,” the data, and a check sum (LRC or CRC). It is traditionally implemented
using RS232, RS422, or RS485 over a variety of media, but also is available as Modbus TCP/IP.
Modbus can be transmitted via two modes: ASCII and RTU. With ASCII, each twelve-bit byte in
a message is sent as 2 ASCII characters, and with RTU, each twelve-bit byte is sent as two four-bit
hexadecimal characters.
13.2.3
32-Bit Numbers & Little Endian
Indices in boldface represent 32-bit values, 2 16-bit values each. Little endian means that the lower-
indexed value contains the lower half (16 least-significant bits) of the 32-bit quantity. Example:
to find the A Active Energy Delivered 32-bit value, use: 65536 * DNP[729] + DNP[728]. 32-bit
register values are scaled according to the values of Kp set separately using PSCSV configuration.
13.2.4
Scale Factors
The scale factors Vmax (maximum rms voltage, volts), Imax (maximum rms current, amperes),
Pmax (maximum per-element power, watts) and Ptmax (maximum total power, watts) are set
using PSCSV configuration. These values are stored internally in the Model 1133A, and are used
as shown on the following pages to scale the various integer results in the DNP/Modbus integer
data structure.
To set up DNP scale factors, see Section 7.6, and Figures 7.6 and 7.7
Содержание 1133A
Страница 4: ...iv ...
Страница 20: ...xx LIST OF TABLES C 1 IRIG B Code Designations 157 E 1 Vorne 34 Output Time Deviation Values 164 ...
Страница 98: ...78 Configuring the Model 1133A Figure 7 30 Upload Configuration Window ...
Страница 110: ...90 Working with Triggers and Downloading Event Records Figure 8 10 List of Event Records ...