Siemens SIMATIC ET 200iSP Operating Instructions Manual page 307

HART signal
The following schematic shows the analog signal with the HART signal superimposed on it
(FSK technique). The signal is composed of sine waves of 1200 Hz and 2200 Hz having an
average value of zero. It can be filtered out using an input filter so that the original analog signal
is available again.
Figure 13-8
HART commands and parameters
You can use SIMATIC PDM to set the parameters of the HART field devices via HART
commands and read these out via HART responses. The HART commands and their
parameters are divided into three groups with the following properties:
● universal
● generally usable
● device specific
Universal command must be supported by all manufacturers of HART field devices; it is
recommended that generally useable commands be supported. In addition there are device-
specific commands, which only apply for the specific field device.
ET 200iSP
Operating Instructions, 11/2017, A5E00247483-07
The HART signal
Analog electronic modules
13.10 Basics of HART
307