Fluidwell E126-P-EG, User Manual

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E126-P-EG User Manual
FW_E126-P-EG_M_v0301-01_EN Page 29
5.5.7 MENU 6: PRESSURE
A “fixed” line pressure value can be used for the calculations:
Enter the fixed line pressure for offset (
6.3: PRESSURE > OFFSET
) and set the span to zero
(
6.2: PRESSURE > SPAN
).
When no pressure sensor is connected, manually calibrate the low input value at
6.5: PRESSURE >
CALIB-LOW
to remove the range error alarm.
6 PRESSURE
6.1 UNIT Programs the displayed unit of measurement for pressure. This setting
does not influence the actual calculations.
6.2 SPAN Determines the measurement range of the (0)4-20 mA pressure sensor
according to the selected measurement unit.
Example : Calculating the span for pressure.
The sensor generates:
●
the minimum signal (4 mA) at a pressure of 2.5 bar.
●
the maximum signal (20 mA) at a pressure of 50 bar.
Therefore, the span should be set at (50 - 2.5 =) 47.5 bar.
6.3 OFFSET
Calculations are based on absolute pressures.
The flow computer must know the measured pressure at minimum signal. In
the above example 2.500 bar must be entered.
When using a gauge type pressure indicator, enter an offset to compensate
for environmental pressure (for example, air pressure, 1.013 bar).
6.4 FILTER Stabilizes the pressure reading.
This digital filter setting produces a more stable but less actual reading.
The filter principal is based on three input values: the filter level (01-99), the
last calculated pressure, and the last average value. The higher the filter
level, the longer the response time of a changed value. Use trial and error
to find the best setting for your application.
RESPONSE TIME ON STEP CHANGE OF INPUT VALUE (IN % OF END VALUE)
Filter value 50% 75% 90% 99%
01 filter disabled filter disabled filter disabled filter disabled
10 7 sec 14 sec 22 sec 44 sec
20 14 sec 28 sec 45 sec 90 sec
30 21 sec 41 sec 68 sec 136 sec
50 35 sec 69 sec 114 sec 228 sec
75 52 sec 104 sec 172 sec 344 sec
99 69 sec 137 sec 227 sec 454 sec
6.5 CALIB-LOW Calibrates the input value for (0)4 mA. This setting is used because the
signal from the pressure sensor might not be exactly 4.0 mA (or 0.0 mA) at
minimum pressure. This function measures the real output value at
minimum pressure.
Make sure the offered signal is correct before calibration takes place
as this has a major effect on the accuracy of the system.
After pressing PROG, three settings can be selected:
●
CALIB: Calibrates the input with the actual (0)4 mA value. After pressing
enter, CAL SET is displayed as soon as calibration is completed. From
that moment, the analog value must be more than the calibrated value
before the signal will be processed.
●
DEFAULT: Reinstalls the manufacture’s values.
●
CAL SET: Selects the last calibrated value.