Maximum And Minimum Value - ABB COMMANDER 1900 Series User Manual

• Maths
5 ADVANCED CONFIGURATION LEVEL...
5.1.4 Maximum and Minimum Value – Fig. 5.1
If the High Value function is selected the maths result holds the value measured on an input variable. If the Low Value
maximum
function is selected the maths result holds the value measured on an input variable. The maths result can be reset to its
minimum
current value by an internal or external digital signal.
Fig. 5.1 shows the process variable from a flow meter which is continually varying with time. The maximum and minimum values
are the highest and the lowest samples taken since an external reset last occurred. The external reset can be independent of the
average reset signal.
5.1.5 Real Time Average
The real time average function averages a continually varying input over a set time scale, between 1 and 1440 minutes
(24 hours). Any process variable, remote set point or other maths block result can be averaged. The maths result can be reset to
its current value by an internal or external signal.
Fig. 5.1 shows the process variable from a flow meter which is continually varying with time. At 0 minutes an external digital input
signal resets the average to the current value measured. The process variable is then sampled for 10 minutes. The average
function result is the average value of the process variable over the 10 minutes sampled.
Maximum Value
Average Time (10 Minutes)
PV
(Flow Rate)
Average
Minimum Value
0 10
Time (Minutes)
External Reset Signal
Fig. 5.1 Example of Average, Maximum and Minimum Functions
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