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2 6 6 H S H MODBUS TR A N S M IT TE R |
P R E SSU R E/ T EM P ER AT U R E M U LT I VA R I A B L E | O I/ 2 6 6 H SH M T- EN R E V. A
6.8 Write Protection
Write protection prevents the configuration data from
being overwritten by unauthorized users.
If write protection is enabled, the “Z” and “S” buttons
(both internal or external) are disabled. However, it is still
possible to read out the configuration data using the
graphical user interface (DTM) or another, similar
communication tool. The control unit may be leaded if
required.
7.3.1 Write protection activation via external push button
When the instrument features the external non-intrusive
push buttons (digit R1 within instrument code), the write
protection function can be performed as follows:
— Remove the identification plate (see figure 17) by
releasing the holding screw lying on the bottom left
corner.
— Use a suitable screwdriver to press the switch down
fully. (see figure 14)
— Then turn the switch clockwise by 90°.
Important. To deactivate the switch, push it down slightly and then
turn counterclockwise by 90°.
6.8.1 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.
6.9
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.
Set Lower Range Value
— Apply the lower range value pressure from the process or
from a pressure transducr. 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)
6.10 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. In case of electronics change to Standard to Advanced HART
(refer to chapter 9.6), 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.
Figure 15: External pushbutton assembly components
Figure 14: Pushbutton functionalities
