Hart Variables - Siemens SIMATIC ET 200SP 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) or via command 9 (for field
devices with HART Rev. 6 or later).
These four HART variables for each channel are always saved in HART variable data record
121 and can be read at any time.
With I/O module AI-DI 16/DQ16x24VDC HART HA, you can also choose from the following
options:
● 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 module. This
makes it easy to process measured values from the field device as input data in the
automation device.
● You can configure 1 or 4 multiHART ranges 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. The multiHART ranges are specified in the properties dialog of 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 you use the multiHART ranges, the input and output address space are also occupied
as follows:
● An additional 6 bytes of input address space and 1 byte of output address space is occupied
for one multiHART range
● An additional 24 bytes of input address space and 4 bytes of output address space is
occupied for four multiHART ranges
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)
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Input/output module AI-DI 16/DQ16x24VDC HART HA (6DL1133-6EW00-0PH1)
Manual, 05/2017, A5E39294170-AA