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HART function
8.1 Use
8.1.2
HART
Definition
"HART" stands for "Highway Addressable Remote Transducer" and enables the digital
communication of several field devices (sensor or transmitter or actuator) via a common data
bus.
The HART functionality also enables you to use the I/O module to exchange data with the
connected field devices. The HART protocol is generally accepted as a standard protocol for
communication with intelligent field devices: HART is a registered trademark of the HART
Communication Foundation (HCF), which owns all the rights to the HART protocol. You can find
detailed information about HART in the HART specification.
8.1.3
HART protocol
Definition
The HART protocol describes the physical form of the transfer: transfer procedures, message
structure, data formats and commands.
Special properties of the HART protocol
The HART protocol is not safety-related!
(FAIW-014)
Description
Each HART message frame sent from the analog module to the connected field device (request
frame) and each HART message frame received from the field device (response frame) has the
following basic structure:
PREAMBLE
PREAMBLE:
STRT:
ADDR:
COM:
BCNT:
STATUS:
76
WARNING
STRT
ADDR
Bytes (0xFF) for synchronizing.
5 bytes
Start character (start delimiter)
Address of the field device (1-byte; short address or 5-byte; long address)
HART command number
Byte count, number of bytes to follow without checksum
HART device status (1st and 2nd status byte). Only present for a response frame.
HART device status (Page 81)
COM
BCNT
STATUS
Equipment Manual, 09/2021, A5E50557845-AA
DATA
CHK
F-AI 8xI 2-/4-wire HART HA
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