Siemens SIMATIC ET 200SP Manual page 91

Structure of the HART-specific settings
Figure B-1
* When the number of HART preamble bytes = 0, the number of preamble bytes requested by
the connected field device are used (at least 5).
When the number of HART preamble bytes = 255, 20 preamble bytes are used for operation.
Input/output module AI-DI 16/DQ16x24VDC HART HA (6DL1133-6EW00-0PH1)
Manual, 05/2017, A5E39294170-AA
Settings
HART operating data records
B.6 HART-specific settings
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