CiDRA SONARtrac HD VF-100 - Manual (Page 85)

Copyright © 2006 CiDRA Corporation Page 10-10
20638-02 Rev 01
consecutive readings, the filter will be reset and the calculated value
will be displayed.
‘State’ – used to ‘Enable’ or ‘Disable’ the Spike Filter.
‘Length’ – defines the number of consecutive measured points that
must be within the reading-to-reading variation range defined by the
‘Percent’ parameter in the filter setup.
‘Percent’ – defines the reading-to-reading variation limit. This is in
units of percent of transmitter operating range.
Therefore, Reading-to-Reading Variation (RV) is the device Maximum
Measurable Value (MaxMV) in ft/sec minus the device Minimum
Measurable Value (MinMV) in ft/sec times the percent of the
Measurable Range ‘Percent’ (MR) input by the user to be used for the
filter; or:
RV = [(MaxMV – MinMV) * MR]
For example, in a device with a velocity MaxMV of 30 fps and velocity
MinMV of 3 fps and a %MR of 10%, reading variations greater than
2.7 fps will be rejected.
RV = [(30 – 3) * 0.10] = 2.7 fps
Therefore, measured points that have measurement variations greater
than 2.7 fps will not be displayed or outputted until the number of
consecutive readings that do not vary by more than RV is greater than
that set by ‘Length’.
10.1.3 Input Config
The Input Config menu is used when optional external sensors (for
example a pressure or temperature transducer) are powered by and
input to the transmitter. The transmitter does not have the capability
to display or transmit these sensor values. Note: These sensor inputs
are not used for VF-100 meter operation.
•
Sensor 1 & 2
- ‘Units’ allows for setting the sensor units to ‘None’ (not used) ‘F’
(temperature degrees F), ‘C’ (temperature degrees C), ‘Barg’
(pressure in Bars gauge), ‘kPag’ (pressure in kilo Pascals gauge),
‘PSIg’ (pressure in pounds per square inch gauge).
- ‘Scale’ allows for setting the range of the input in units of measure
(‘Units’) per mA.
- ‘Offset’ allows for inputting an offset in mA due to a non-zero
milliamp sensor output range. The offset is calculated by the equation
y=mx+b where: y is a value within the transducer range, m is the
transducer range divided by the milliamp output range, x is the
milliamp output at the ‘y’ value, and b is the offset.