ICP DAS USA HRT-710, Руководство пользователя

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HRT-710 User Manual (Version 1.24, June/2015) PAGE: 103
Appendix B: Command Format
The HART data format of MB address is divided into the
―Normal‖ and
―Simple‖ format.
1. Normal format :
When read / write HART data by Modbus, the MB data format is HART
standard command format.
2. Simple format :
When read / write HART data by Modbus, the MB data format is simple
format (omit the
―Response Code‖ and ―Unit‖ data).
In this mode, the HMI
or SCADA software can read or write HART data easily. Now, it only
supports HART command number 1, 2 and 3.
The simple format of HART command is shown as below
:
(1) Command 1: (Read Primary Variable)
Request data bytes : none
Response data bytes : 4
[Index Format Description]
Byte 0~3 : float Primary Variable
(2) Command 2: (Read P.V. Current and Percentage of Range)
Request data bytes : none
Response data bytes : 8
[Index Format Description]
Byte 0~3: float Primary Variable Current
Byte 4~7: float Primary Variable Percentage of Range
(3) Command 3: (Read Dynamic Variables and P.V. Current)
Request data bytes : none
Response data bytes : 20
[Index Format Description]
Byte 0~3: float Primary Variable Current
Byte 4~7: float Primary Variable
Byte 8~11: float Secondary Variable
Byte 12~15: float Tertiary Variable
Byte 16~19: float 4th Variable