Siemens SIMATIC ET 200SP HA Equipment Manual page 70

Parameters, diagnostics messages and address space
A.7 Address space
Output range
In the configuration with a multiHART area, there is one byte in the output area.
QB x
Evaluating HART variables
If you have configured (mapped) HART variables for the I/O module, then 4 HART variables with
5 bytes each are stored in the input address space.
Each HART variable consists of a 4-byte real value and a 1-byte quality code. The quality code
describes the validity of the value.
The assigned HART variables are automatically updated by the module and can be used directly
in the user program.
Evaluating the multiHART area
You can select the multiHART area in the parameter assignment dialog.
The multiHART range occupies 1 byte in the output range (command) and 6 bytes in the input
range (1 byte acknowledgment + 5 bytes HART variable).
You can read all HART variables available in the module using the multiHART area. To do so, you
must use the command byte in the output area to request a HART variable from the module.
The command byte identifies the requested HART variable (HART variable reference):
HART variable reference
Bit 0...3:
Variable identifier
1 = Primary
2 = Secondary
3 = Tertiary
4 = Quaternary
The command is acknowledged via the acknowledgment byte in the input range. As soon as the
HART variable reference requested using the command can be read, the requested HART
variable can be evaluated.
If you leave the command byte of the multiHART range unchanged, the module will
continuously update the corresponding HART variable.
If an invalid HART variable reference is requested, this is also acknowledged accordingly. The
value of the corresponding HART variable is then zero and the quality code is signaled with 0x37
(initialization value of the analog module).
Example:
The primary variable of channel 4 is to be read.
70
Command multiHART range
Bit 4...7:
Channel number 0...3
AI 4xI 2-/4-wire HART ISOL HA
Equipment Manual, 07/2022, A5E50101523-AB
H