E018-P
User Manual
FW_E018-P_M_v0301-01_EN
Page 27
6
LINEARIZATION
6.G LINEARIZATION
This setting is used to easily enable or disable the linearization function.
When linearization is disabled, the K-factor set at
1.3: TOTAL > K-FACTOR
and
2.4: FLOWRATE > K-FACTOR
will be used for the calculation of total and flowrate.
When linearization is enabled, the K-factor set at
1.3: TOTAL > K-FACTOR
and
2.4: FLOWRATE > K-FACTOR
will be used as
KF0
in the linearized calculations for
total and flowrate.
6.H DECIMALS
FREQUENCY
Determines the number of decimals for the frequency entered.
5.5.7
MENU 7: ANALOG OUTPUT
An analog 4-20 mA signal is generated according to the flowrate with a 12 bits resolution. The
settings for Flowrate influence the analog output directly and should be configured first. The
relationship between rate and analog output is set with the following functions.
Rate Min and Rate Max correspond with the HART variables PV URV and PV LRV and determine
the range of the analog output.
The number of decimals displayed for Rate Min and Rate Max depend on
2.3: FLOWRATE > DECIMALS
.
However, if a value was entered that does not fit on the display (for example, via the HART
interface), the number of decimals displayed are rounded off.
The measuring units (for example, L/min) and the time depend on the settings in
2.1: FLOWRATE > UNIT
and
2.2: FLOWRATE > TIME
are displayed during editing.
Example
: Calculating the actual output current
Suppose Rate-Min (PV-URV) is set at 1600 l/sec and Rate Max (PV-LRV) at 0 l/sec.
What will be the value of the analog output when the actual flowrate is 1000 l/sec?
● Analog output current = 1000/1600 * (20 mA-4 mA) + 4 mA = 14 mA
7
ANALOG OUTPUT
7.1 RATE MIN (4MA)
Primary Variable Lower Range Value (PV-LRV)
Enter the flowrate at which the output should generate the minimum signal
(4 mA) – in most applications at flowrate “0”.
If required, you can program the analog output 'up-side-down'. The 4 mA
then represents the maximum flowrate.
For example, enter 800 L/min.
7.2 RATE MAX (20MA)
Primary Variable Upper Range Value (PV-URV)
Enter the flowrate at which the output should generate the maximum signal
(20 mA) – in most applications at maximum flow.
If required, you can program the analog output 'up-side-down'. The 20 mA
then represents the minimum flowrate.
For example, enter 0 L/min.
7.3 TUNE MIN (4MA)
Use this setting to precisely tune the minimum analog output value (initial
value is 4 mA). This value can differ slightly due to ambient influences such
as temperature.
Before tuning the signal, make sure the analog signal is not being
used for any application.
After pressing PROG, the current will be about 4 mA. The current can be
increased / decreased with the arrow-keys and is directly active. Press
PROG to store the new value.
7.4 TUNE MAX (20MA)
Use this setting to precisely tune the maximum analog output value (initial
value is 20 mA). This value can differ slightly due to ambient influences
such as temperature.
Before tuning the signal, make sure the analog signal is not being
used for any application.
After pressing PROG, the current will be about 20 mA. The current can be
increased / decreased with the arrow-keys and is directly active. Press
PROG to store the new value.