Endress+Hauser Prosonic Flow 90, Руководство по эксплуатации

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5 Operation Proline Prosonic Flow 90
48 Hauser
5.5 Communication (HART)
In addition to local operation, the measuring device can also be configured and measured values
obtained by means of the HART protocol. Digital communication takes place using the 4...20 mA
current output HART (see Page 39).
The HART protocol allows the transfer of measuring and device data between the HART master and
the field devices for configuration and diagnostics purposes. The HART master, such as a handheld
terminal or PC-based operating programs (such as “ToF Tool - Fieldtool Package”), require device
description (DD) files. They are used to access all the information in a HART device. Information is
exclusively transferred using so-called “commands”. There are three different command groups:
Universal commands:
All HART device support and use universal commands. The following functionalities are linked
to them:
• Recognizing HART devices
• Reading digital measured values (volume flow, totalizer, etc.)
Common practice commands:
Common practice commands offer functions which are supported and can be executed by most but
not all field devices.
Device-specific commands:
These commands allow access to device-specific functions which are not HART standard. Such
commands access individual field device information, amongst other things, such as empty/full pipe
calibration values, low flow cut off settings etc.
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Note!
The measuring device has access to all three command classes. On Page 52, you will find a list with
all the supported “Universal Commands” and “Common Practice Commands”.