EN.IO.APC.APR.ALW
Revision 02.A.005/2020.06
31
9.3. Correction of impact of transmitter mounting position on site
– pressure reset
Once the transmitter is mounted in a target location, it must be reset. This operation will eliminate the
possible influence of the mounting position on the indication of pressure/differential pressure. In order
to do so:
−
in case of relative pressure transmitter without pressure supplied (vented), perform the pres-
sure reset operation using the local MENU or HART communication;
−
in the case of a differential pressure transmitter, at compensated pressures on the L and
H supply, perform the pressure reset operation by means of local MENU or HART communi-
cation;
−
in case of absolute pressure transmitter the resetting is only possible with an absolute pres-
sure calibration device. Otherwise an attempt to reset the transmitter will display an error.
9.4. Correction of impact of spacing of distance separators on site
In pressure/differential pressure transmitters with distance separator(s), it is required to make an ad-
justment depending on the impact of the separator position. The adjustment is made after the trans-
mitter has been installed on site, before filling the plant. To do t
his, select “SETLRV” and “BYPRES” in
the transmitter menu. Up
on acknowledgement (“DONE”), a 4 mA signal, including the impact of the
separator positions, is set in the transmitter. The
20 mA signal is set by selecting “SETURV”. For level
measurements, fill the tank to a level corresponding to 2
0 mA, select “BYPRES” and confirm. If it is
not possible to fill the tank/plant to the value corresponding to the 20 mA signal, the URV value may
be set by selecting “BYVALU” function and entering the value. The value (in pressure units) is calcu-
lated by adding the planned measurement span value to the pressure value (PV) obtained after set-
ting the LRV signal (4 mA).
Once the transmitter parameters have been entered and it has been reset at the workstation,
it is required to:
−
secure the device against the possibility of making changes in the local setpoint
change MENU;
−
set your own password different from defaul
t password of “00000000”. The new pass-
word may consist of any combination of 8 hexadecimal characters 0...9,
A…F. Store the
password in a safe place. If the password is lost, its restoration or resetting to factory
settings may only be performed by the manufacturer;
−
activate the setpoint change lock to secure the transmitter against accidental, uninten-
tional change of parameters.
Pressure reset can be done via local setpoint change MENU or HART communication. The remaining
operations described in this section may only be performed using HART communication.
For Exd or Exi/Exd type transmitters, opening the housing cover in the hazardous zone in
order to use the local setpoint change MENU is forbidden.
9.5. Flow measurements
Differential pressure transmitter APR-2000ALW can be used for venturi flow measurements. Flow
measurements often require setting of pressure-processing characteristics for output current setpoints
other than linear. In APR-2000ALW transmitter the following characteristics are available for the user:
−
linear characteristics;
−
second-stage root characteristics with relay characteristics and 0,2% hysteresis in the dead-
band
−
manufacturer’s dual linear characteristics No.1+ second-stage root characteristics for constant
deadband = 0,6% of setpoints;
−
manufact
urer’s single linear characteristics No.2+second-stage root characteristics and 0,2%
hysteresis in the deadband;
−
square characteristics;
−
special characteristics based on user-modified table.
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