Command Classification In The Hart - Endress+Hauser iTEMP HART TMT162 Bedienungsanleitung

TMT162
Endress+Hauser
5.3.4

Command classification in the HART

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The HART protocol makes it possible for configuration and diagnostic purposes to transmit
measured and device data between the HART
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HART masters such as the handheld module or PC-based operating programs (e.g. FieldCare)
require so-called device description files (DD = device descriptions, DTM), these make it possible
to access all information in a HART
using "commands".
There are three command classifications:
• Universal commands
Universal commands are supported and used by all HART
the following functionality:
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– Recognizing HART devices
– Readout of digital measured values
• Common practice commands:
These general commands offer functions that are supported or used by some but not all field
devices.
• Device specific commands
These commands enable access to device specific functions that are not HART
Such commands access, among other things, individual field device information.
Chapter 6.4.2 contains a list of all HART
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master and the respective field device.
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device. Transmission of such information is done exclusively
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devices. Combined are for example
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commands supported.
Operation
protocol
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standardized.
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