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Functions
7.4 Function Group Measuring Functions
SITRANS F M TRANSMAG 2
Operating Instructions, 11/2009, A5E00102775-07
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7.4 Function Group Measuring Functions
Flow (Menu item 3.1)
You have the following setting options in this menu:
● Engineering unit, menu item 3.1.1
This function offers you the possibility of choosing between units of volume flow (volume
unit per time unit) or mass flow (mass unit per time). If a unit of mass is selected, it is
mandatory to enter the density of the medium in menu item 3.1.4.
● Flow Upper Range Value (URV), menu item 3.1.2
The full scale value is set depending on the nominal width of the sensor and the valid
speed range (0.25 - 12 m/s). The start of scale value is always 0 (zero).
Note
Devices with PROFIBUS PA
Although the profile parameter for the start of scale value (0%) can always be written by
acyclic communication, values not equal to 0 are rejected.
The output scale does not appear in the local operating unit. It is always automatically set
to be identical with measuring scale, i.e. the profile parameters start / end of the output
scale are automatically set to 0 or "URV". Other values are rejected in acyclic PROFIBUS
communication.
The set URV only has an influence on the percentage defined values such as "flow in %",
hysteresis and the digital output 1.
Measured values outside this range are also reported by PROFIBUS as valid measured
values providing they are within the sensor limits. The sensor limits for flow depend on
the nominal width and correspond to a flow velocity range of about -13m/s to +13m/s.
Measured values outside the sensor limits are displayed but are no longer within the
specified range; "uncertain, nonspecific, low limited" or "uncertain, nonspecific, high
limited" is then reported as a measured value status.