Endress+Hauser Silometer FMC 672 Z, Инструкция по установке и эксплуатации

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5 Linearization
For tanks in which volume is not directly proportional to level, e.g. for horizontal cylinders
or tanks with conical outlets, the linearization converts the level measurement into a
measurement of capacity.
Parameters for linearization are selected at fields V2H0
…
V2H8 for channel 1 and
V6H0
…
V6H8 for channel 2. In addition the field V3H0/V7H0 determines whether the
associated calibration is to be performed in level or volume units (0 = level, default, 1 =
volume). For simplicity, the fields for channel 1 only are used in the procedures. The
following linearization modes can be entered at V2H0/V6H0:
0 = linear, default value
1 = horizontal cylinder
2 = factory set
3 = manual entry
4 = cancel current setting
The most frequently used modes, horizontal cylinder and manual entry are described
in Sections 5.1. and 5.2, all others in Section 5.3.
Two important rules must be observed when performing a linearization:
•
All level (or volume) entries must be made in the units you have chosen
during calibration
•
The levels for calibration and linearization must be referenced to the same
datum point.
After linearization After linearization:
•
The volume of liquid currently in the tank can be read from V0H0/V4H0.
•
The level before linearization can be read from V0H9/V4H9.
•
The 0/4
…
20 mA signal range must be set in the volume units entered.
•
The relay switch points must be set in the volume units entered.
BA064E38
Datum level for
calibration and
linearization must be
the same
Last level entry must
correspond to 100% full
0/4
…
20 mA signal
follows volume
Level (or volume) in
units used for
calibration
100%
0%
0 50 100 200 270 m
3
Units of volume
Fig. 5.1:
Linearization for a vessel with a
conical outlet
Silometer FMC 672 Z/677 Z Chapter 5: Linearization
27