Configure process measurement
Result:
• Under conditions of zero flow, the mA output is 12 mA.
• Under conditions of forward flow, for flow rates between 0 and +100 g/s, the mA output varies
between 12 mA and 20 mA in proportion to (the absolute value of) the flow rate.
• Under conditions of forward flow, if (the absolute value of) the flow rate equals or exceeds 100 g/s,
the mA output is proportional to the flow rate up to 20.5 mA, and will be level at 20.5 mA at higher
flow rates.
• Under conditions of reverse flow, for flow rates between 0 and −100 g/s, the mA output varies
between 4 mA and 12 mA in inverse proportion to the absolute value of the flow rate.
• Under conditions of reverse flow, if the absolute value of the flow rate equals or exceeds 100
g/s, the mA output is inversely proportional to the flow rate down to 3.8 mA, and will be level at
3.8 mA at higher absolute values.
t
Example:
Flow Direction
=
Reverse
Configuration:
•
Flow Direction
=
Reverse
•
Lower Range Value
= 0 g/s
•
Upper Range Value
= 100 g/s
Result:
• Under conditions of forward flow or zero flow, the mA output is 4 mA.
• Under conditions of reverse flow, for flow rates between 0 and −100 g/s, the mA output level varies
between 4 mA and 20 mA in proportion to the absolute value of the flow rate.
• Under conditions of reverse flow, if the absolute value of the flow rate equals or exceeds 100 g/s,
the mA output will be proportional to the absolute value of the flow rate up to 20.5 mA, and will
be level at 20.5 mA at higher absolute values.
Flow Direction
and frequency outputs
Frequency outputs are affected by
Flow Direction
only if
Frequency Output Process Variable
is set to a flow
variable. Frequency output levels for different combinations of
Flow Direction
and actual flow direction
are shown in Table 5-5 .
Table 5-5
Effect of the
Flow Direction
parameter and actual flow direction on frequency outputs
Actual flow direction
Flow Direction
setting
Forward
Zero flow
Reverse
Forward
Hz > 0
0 Hz
0 Hz
Reverse
0 Hz
0 Hz
Hz > 0
Bidirectional
Hz > 0
0 Hz
Hz > 0
Absolute Value
Hz > 0
0 Hz
Hz > 0
Negate Forward
Zero
(1)
0 Hz
Hz > 0
Negate Bidirectional
Hz > 0
0 Hz
Hz > 0
(1) Refer to the digital communications status bits for an indication of whether flow is positive or negative.
82
Micro Motion 9739 MVD Transmitters