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PRESYS
|
Instruments
DIRECT - enables a user-configurable scale for the pressure sensor. When
YES is selected, the indication scale on display is the own scale of the pressure
sensor (for instance: 0 to 5.000 psi; 0 to 250.0 psi, etc.). In case the NO option is
selected to the direct mode, it takes the scale configured by the user, by means of
the Lim Low, Lim High, Eng Low and Eng High mnemonics. For example, in a
process where pressure varies from 3 to 15 psi and one requires the indication to
show 0 to 100.0%; it is necessary to configure: Lim Low = 20.0%, Lim High = 100.0%
Eng Low = 0.0% and Eng High = 100.0%. Note that Lim Low and Lim High are
expressed as % of the sensor full scale (which is 15 psi in this example). The NO
option belongs both to pressure sensors and linear ones.
UNIT - is the option which allows automatic conversion between several
pressure units available (psi, atm, inH
mbar, kPa and mmH
°F for temperature indication.
The UNIT option is only effective when the DIRECT mode is selected (YES)
for pressure. In the scale mode for pressure indication (NO is atributed to the
DIRECT mnemonic), the UNIT option has no effect on the indication on display.
The adjustable parameter span shown on figure 14 is given below.
Mnemonic
LIM LOW
LIM HIGH
ENG LOW
ENG HIGH
CUT-OFF
OFF SET
FILTER
(*) EU - Engineering Units
When selecting a linear input or pressure sensor, one must configure its scale
(SCALE option). Define two points P1(Lim Low, Eng Low) and P2(Lim High, Eng
High), as illustrated in figure 15. Lim Low represents the value of the electrical signal
DCY - 2057 Pressure Controller
O) to mesure the input signal as pressure. It also selects °C or
2
Parameter
input signal associated
to Eng Low
input signal associated
to Eng High
display indication
associated to Lim Low
display indication
associated to Lim High
minimum square root
value
constant added to
display indication
time constant of first
order digital filter
2
O, kgf/cm
, mH
O, inHg, mmHg, cmHg, bar,
2
2
Adjustable
0.0 to 100.0
0.0 to 100.0
-999 to 9999
-999 to 9999
0 to 5
-999 to 9999
0.0 to 25.0
Factory
Units
Value
0.0
%
100.0
%
0.0
EU*
100.0
EU
0
%
0
EU
0.0
seconds
Operation
Page 28
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