Setting Zero Head
Many PMDs start flowing higher than the traditional empty distance of the application.
You can account for the flow in one of two ways:
2.15.3.5. Zero Head Offset
1.
Use
value. Possible head =
2.15.3.3. Maximum Head
Note:
High Calibration Point
Make sure you set
Zero Head Offset
max. head
material surface
head
zero head
2.2.5. Far Range
2.
Use
above the bottom of the channel. It should be used if the surface monitored can fall
2.2.1. Low Calibration Point
past the
LOE. The value is added to
range of the transducer.
The examples on the following pages show both methods.
A5E33329501
to have OCM calculations ignore levels below that
2.2.1. Low Calibration Point
is preset to
and is not updated when
2. 1 5.3.3. Maximum Head
. (Refer to PMD supplier documentation for Maximum Head.)
where the empty level is set to the bottom of the weir, and
2.2.1. Low Calibration Point
SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS
2.2.2. High Calibration Point
minus
2.2. 1 . Low Calibration Point
2.15.3.5. Zero Head Offset
to the correct value when using
level in normal operation without reporting an
and can be greater than the
2.2.2.
minus
is used.
2.15.3.5.
.
sensor ref. point
high cal. point
low cal. point
far
range
Page 99
.