Allen-Bradley 1794-IE8H, Руководство пользователя, Страница: 71 / 146

Publication 1794-UM063A-EN-P - March 2006
Calibrate Your Module 5-3
1794-IE8H Calibration
Command Structure
Calibration of the HART I/O module is performed using data structures and
MSG Ladder-logic instructions. The MSG instruction sends the data structure
to a dedicated attribute in the FLEX HART I/O module and the associated
response is read from the same attribute. The data structure contains
commands and its associated parameters. Depending on the command, they
are either writable or readable. Only one access, either read or write, is
executable at a time.
The Calibration data structure has four members: Command, Item, Data1, and
Data2.
Table 5.2 Calibration Data Structure
Attribute Field Size Implementation Description Value (Hex) Access
67
hex
4 byte struct { Conditional Read or write
USINT Command; Calibration command;
USINT Item; Additional command
information;
USINT Data1; Data according to command;
USINT Data2; Data according to command
} Calibration;