Siemens Multi Panel MP270 SIMATIC HMI, Руководство по эксплуатации оборудования

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Operating Special Screen Objects
5-11
MP270 Equipment Manual
Release 01/99
5.3 Trend Graphics
Purpose
Trend graphics on the MP270 provide an especially clear visualization of
continuous process data values. In the case of processes which change very
slowly, it is possible to visualize trends of previous events, thus enabling estimation
of future trends within a process. On the other hand, the output of data concerning
processes which run extremely quickly enables large quantities of data to be
evaluated by simple means.
Configurable properties
The MP270 can depict several different trends in the trend graphic at the same
time. The following properties are among those which can be configured for a trend
graphic:
Representation
Different trends can appear in different colors, as lines, dots or bars.
Types of trend
– Real-time trend
The MP270 reads just one trend value from the PLC per pulse or trigger and
inserts it in the trend displayed.
– Pattern trend
By setting a trigger bit, the MP270 reads all the trend values from the PLC
simultaneously and displays them as a trend.
Trigger
The type of trigger determines how the MP270 reads the trend data:
–
Pulse triggering
The MP270 reads the data from the PLC within a defined time matrix.
–
Bit triggering
The MP270 reads the data, triggered by an event. The event is triggered by
the PLC through setting a defined bit.
Limit values
The MP270 implements color changes to visually indicate that configured limit
values have been reached or exceeded.