4-7
Device Software Functions
LRV (Lower Range Value)
Reset the lower range value (LRV), or analog output zero, to change the
size of the range (or span) between the URV and LRV. Under normal
circumstances, the LRV should be set to a value near the minimum
expected flow rate to maximize resolution. The LRV must be between
–30 ft/s to 30 ft/s.
NOTE
The LRV can be set to a value greater than the URV, which will cause
the analog output to operate in reverse. In this mode, the analog output
will increase with lower (more negative) flow rates.
Example
If the URV is greater than the LRV, the analog output becomes 3.9 mA
when the flow rate falls below the selected 4 mA point.
The minimum allowable span between the URV and LRV is 1 ft/s. Do
not set the LRV within 1 ft/s of the 20 mA point. For example, if the
URV is set to 15.67 ft/s and if the desired URV is greater than the LRV,
then the highest allowable analog zero setting would be 14.67 ft/s. If the
desired URV is less than the LRV, then the lowest allowable LRV would
be 16.67 ft/s.
Line Size
The line size (tube size) must be set to match the actual flowtube
connected to the transmitter. The size must be specified in inches
according to the available sizes listed below. If a value is entered from a
control system or HART Communicator that does not match one of
these figures, the value will be rounded to match the nearest option.
The line size (inches) options are as follows:
NOTE
The second line on the LOI screen, MAX FLOW, is strictly for
informational purposes. The MAX FLOW value is identified as URV on
the HART Communicator and most control systems.
HART Fast Keys 1, 3, 4
LOI Key Aux. Function
HART Fast Keys 1, 3, 5
LOI Key Tube Size
0.1, 0.15, 0.25, 0.30, 0.50, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 14, 16,
18, 20, 24, 28, 30, 32, 36, 40, 42, 48, 54, 56, 60, 64, 72, 80
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