Write Protection Activation Via Dip Switch; Correcting The Lower Range Value / Zero Shift; Set Lower Range Value; Correct The Zero Shift - ABB 266 HART Series Operating Instruction

Figure 44: Write-protection pushbutton

7.4.2 Write protection activation via dip switch

Standard instruments do not feature the external, non intrusive
Zero, Span and Write Protection push buttons. To activate this
function it is necessary to proceed as detailed below:
— Remove instrument cover and the integrated digital LCD
display (if installed).
— On the connection board, place dip switch 4 in "up"
position.

7.5 Correcting the lower range value / zero shift

During installation of the transmitter, transmitter, zero shifts
caused by mounting (e.g., a slightly oblique mounting position
due to a remote seal, etc.) may occur; these must be corrected.
Important. The transmitter must have reached its operating
temperature (approx. 5 min. after startup, if the transmitter has
already reached the ambient temperature) in order to perform zero
shift correction. The correction must be made at dp (or p) = 0.
Important. The button unit must be available for this purpose
(option R1). In case external push buttons are not available, act on
the connection board directly by depressing with a screwdriver the
dedicated internal push buttons. Operating the buttons using a
magnetic screwdriver is not permitted because it may generate
some interferences with the magnetic pickup system.

7.6 Set lower range value

— Apply the lower range value pressure (4 mA) from the
process or from a pressure transducer. The pressure
must be stable and applied with a high level of accuracy
<< 0.05 % (observing the set damping value).
— Press the "Z" button (external pushbutton - option R1) or
the "Zero" command on the connection board of the
pressure transmitter for few seconds. The output signal
will be is set to 4 mA. The span will remain unchanged.
Important. Setting the lower range value by using the push buttons
is possible if the write protection is not enabled.

7.7 Correct the zero shift

The zero shift caused by the installation may be cancelled in
different ways:
— Pressing the "Z" button (under the identification plate on the
top of the transmitter, if present) or the "Zero" internal button
(on the connection board) for few seconds will cause the
output to go at 4 mA.
— It is also possible to align the digital PV value to zero.
To accomplish it raise the dip sw. 3 on the communication
board to the up (1) position and press the zero button.This
functionality will align the PV digital value to 0 and if the
calibrated span it is zero based, the output will go at 4 mA.
— Using the optional LCD with keypad ("Configuration of
the pressure transmitter using the integral LCD HMI" for
further information).
Important. The procedure described above does not affect the
physical pressure shown; it only corrects the analog output signal.
For this reason, the analog output signal may differ from the
physical pressure (PV Value) shown on the digital display or the
communication tool. To avoid this discrepancy, correct the zero
position shift (zero shift) via the PV-BIAS/OFF-SET functionality.
7.8 Installing/Removing the external push buttons
(option R1)
— Loosen the screws that fix the nameplate plate and slide
the plate to gain access to the local adjustments.
— Loosen the push buttons assembly screws (1) holding
down the plastic element which is spring loaded.
— Remove the gasket (3) which is positioned below the
pushbutton plastic cover (2).
— The three push buttons (4) and the relevant springs (5)
can now be removed from their seat.
Figure 45: External pushbutton assembly components
Important. In case of electronics upgrade from Standard to Advanced
HART (refer to chapter 10.6), external, non-intrusive push buttons can
be installed (if not selected with the option R1) by ordering the
commercial code DR1014. Please refer to local ABB representative.
2600T Series Pressure transmitters | OI/266/HART-EN Rev. M 33
7 Commissioning