Hart Variables - Siemens SIMATIC ET 200SP HA Manual

HART function

6.3 HART variables

6.3 HART variables
Introduction
Numerous HART field devices make available additional measured quantities (e.g. sensor
temperature).
A maximum of four HART variables supported by the connected field device are read cyclically
for each channel with enabled HART functionality. The HART variables are read automatically
via the HART command 3 (for field devices with HART Rev. 5 and 6) or via command 9 (for
field devices with HART Rev. 7 or later).
These four HART variables per channel are always stored in HART variable data record 121
and can be read at any time.
In addition, you can optionally configure the following:
● You can map a maximum of 8 HART variables to the input address space of the I/O module.
The HART variables are assigned to a channel in the properties dialog of the I/O module.
This allows you to easily process measured values directly from the field device as input
data in the automation device.
● You can configure a multiHART area in the input/output address space of the I/O module.
You can read all HART variables available in the I/O module with each of these multiHART
areas. You specify the multiHART area in the properties dialog for the I/O module.
Address assignment
Each HART variable occupies 5 bytes of input data. As soon as you configure (map) at least
one HART variable in the input address space, the addresses for all 8 tags are assigned (40
bytes).
When the multiHART area is used, an additional 6 bytes of input address space and 1 byte of
output address space are assigned.
Configuration of HART variables
You can configure up to 8 HART variables in the properties dialog of the I/O module. You select
these from the four HART variables provided by each channel:
● PV (Primary Variable)
● SV (Secondary Variable)
● TV (Tertiary Variable)
● QV (Quaternary Variable)
When HART mode is enabled, the I/O module cyclically reads the variables provided by the
connected field devices itself and makes them available in the configured input address space.
Configuring of a multiHART area
You can use a multiHART area for the AI 16xI 2-wire HART HA I/O module. You select whether
or not to use a multiHART area in the properties dialog of the I/O module.
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Analog Input Module AI 16xI 2-wire HART HA ( 6DL1134-6TH00-0PH1)
Manual, 11/2017, A5E39408968-AB