7 ND90 71 en
31
5.7.3 Viewing of latest event
You may view the latest event by pressing the
=
and
-
keys simultaneously in the measurement monitoring view.
The message is scrolled on the top row of the display twice.
You may stop the scrolling by pressing the
?
key. By
pressing the
=
key, the message will disappear.
For the list of events see Chapter 7.
5.7.4 Fail-safe active
When the ND detects serious device failure (setpoint, valve
position and control signals) it enters fail-safe mode, which
drives the control valve into the position defined in the
parameter controller fail action (
PFA
). Fail-safe mode is indi-
cated by the display as seen in Fig. 30. The error message is
displayed until the cause of error is eliminated and the ND
unit is restarted, i.e. the power is momentarily discon-
nected.
5.7.5 Reduced performance
When the ND detects spool valve measurement failure, it
enters reduced performance mode. This is indicated by the
blinking
&
in the display, see Fig. 31.
In reduced performance mode valve control can not be
optimized. To correct the problem replace the spool valve
assembly and perform auto calibration.
5.8
Write protection
HART write protection, ND9000H and ND7000H
The ND9000H and ND7000H are delivered from the factory
with the default set as HART write protection OFF. Reading
and changing parameters is allowed. HART protection may
be enabled with a switch (DIP1) located on the communica-
tion circuit board under the Local User Interface module.
Changes that may influence the valve position cannot be
made using the FieldCare software or HART hand held
when switch no. 1 (on the left-hand side of the switch
block) is ON, Fig. 33.
Write protection, ND9000F, ND9000P
The ND9000F/ND9000P is delivered from the factory with
HW write protection OFF as the default setting. Reading
and changing parameters is thus allowed.
Write protection can be enabled with the switch (DIP1)
located on the circuit board, Fig. 34.
The simulation can be enabled with the switch (DIP2)
located on the circuit board, Fig. 34.
Write protection protects all write access to all writeable
parameters of the device. Changing the parameters from
the LUI or fieldbus configurator is thus not allowed.
The simulation switch is OFF as the default setting. A0 block
simulation is thus disabled. The simulation can be enabled
with the switch (DIP2) located on the circuit board, Fig. 34.
Fig. 30
Example of failsafe display
Fig. 31
Reduced performance display
scrolling text
Fig. 32
HART write protection, ND9000H and ND7000H
Fig. 33
Write protection, ND9000F and ND9000P
12
ON
12
ON
