Siemens SITRANS FEC920, Руководство пользователя

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FEC920: USER GUIDE
Page 84 September 18
Figure 76 shows a typical totalizer configuration page.
Figure 76 Typical totalizer configuration menu
Descriptor Allows the user to enter a descriptor (20 characters max.) for the totalizer.
Type Select: Math, Counter or Totalizer.
Operation Allows the user to enable (‘On’) or disable (‘Off’) the totalizer.
PV Read-only. This is the dynamic output value of the totalizer.
Status Read-only. Shows the status of the totalizer.
Resolution The Resolution parameter allows the number of decimal places (up to six) to be set for the
totalized value as displayed on the instrument panel. It does not affect the resolution of
the totalization process. Up to six decimal places may be set for the totalized value.
Units Allows a units string of up to five characters to be entered for the totalized value.
Units Scaler Allows a units scaler to be selected. Typically this will be used to scale between unit types
rather than to influence time period.
One example of this would be when an input is measured in Litres/Minute, and Period has
been set to 1Minute. If UnitsScaler is set to 1 then the total volume will be measured in
Litres. If the volume is required in Cubic Metres then conversion of the total will be needed.
There are 1000 Litres in a Cubic Metre so the UnitsScaler should be set to 1000. This
produces an additional division of 1000 and results in a total output in Cubic Metres.
Another example would be a requirement for the output in Gallons rather than litres, still
with an input being measured in Litres/Minute. There are 4.54609 litres in an imperial
gallon so the UnitsScaler would be set to 4.54609. (For a US Gallon the figure would be
3.78541.)
Low Cut Off Used to restrict the input operating range of the totalizer. Minimum value = -100 000
High Cut Off Used to restrict the input operating range of the totalizer. Maximum value = 100 000
Low Cut Off and High Cut Off are particularly important as they directly affect the
totalization process. Together these two parameters define the range of valid inputs to the
totalization process. If Input1 value lies between them, then the input is considered valid
Figure 75 Using cascaded counters to expand
the totalization range.
Totalizer
Counter 1
Counter 2
Input 1
Input 1
Input 1
Rollover
Rollover
Rollover
1 to 10
6
10
6
to 10
12
10
12
to 10
18
VirtualChan1
Totaliser
On
180.3625 units
Good
4
units
Descriptor
Type
Operation
PV
Status
Resolution
Units
Virtual Channel.1.Main
Units Scaler
Low Cut Off
High Cut Off
Input1
Period
Preset
Preset Value
Rollover
Rollover Value
Disable
1
0
100000
327.1
1 sec
No
0
No
1000000
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