ABB 266 DDS, Manual

Page: 21 / 60

2 6 6 DDS H A RT |
P R E SSU R E T R A N SM I T T ER S | O I/ 2 6 6 D DS - EN R E V. B 21
6 Commissioning
General remarks
Once the pressure transmitter has been installed, it is put into
operation by switching on the operating voltage.
Check the following before switching on the operating voltage:
• Process connections
• Electrical connection
• The impulse line/s and the measuring chamber of the
measuring equipment must be completely filled with the
measuring medium.
The transmitter can then be put into operation.
To do this, the shut-off valves must be actuated in the following
order (in the default setting, all valves are closed):
1 Open the shut-off valve on the pressure tap connection.
2 Open the positive shut-off valve.
To put the transmitter out of operation, carry out the steps in
reverse order.
If, when using “intrinsically safe” transmitters, an ammeter is
connected to the output circuit or a modem is connected in
parallel while there is a risk of explosion, the sums of the
capacitances and inductances of all circuits, including the
transmitter (see EC-typeexamination certificate) must be
equal to or less than the permissible capacitances and
inductances of the intrinsically safe signal circuit (see EC-
type-examination certificate for the supply unit).
Only passive or explosion-proof devices or indicators may be
connected. If the output signal stabilizes only slowly, it is
likely that a large damping time constant has been set on the
transmitter.
Analog and HART Communication models
If the pressure applied falls within the values indicated on the
name plate, the output current will be between 4 and 20 mA. If
the pressure applied falls outside the set range, the output
current will be between 3.5 mA and 4 mA if the range is
undershot or between 20 mA and 22.5 mA if the range is
overshot (depending on the respective configuration).
Standard setting for normal operation
3 .8 mA / 20 .5 mA
A current that is < 4 mA or > 20 mA may also indicate that the
microprocessor has detected an internal error. In this case the
alarm output can be configured both via the local LCD with
keypad, via an external Hart hand held terminal or via a DD/FDI
based configuration tool (FIM).
Standard setting for error detection (alarm)
3 .6 mA / 21 mA
The graphical user interface (DD/FDI) or the LCD integral
display (if installed) can be used to diagnose the error.
A brief interruption in the power supply results in
initialization of the electronics (program restarts).
• Lower limit: 3.6 mA (configurable from 3.6 to 4 mA)
• Upper limit: 21 mA (configurable from 20 to 23 mA
Factory setting: high alarm current (21.0 mA)
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 (DD/FDI) or another, similar communication tool. The
control unit may be leaded if required.
Write protection activation via external push button
When the instrument features the external non-intrusive
push buttons, the write protection function can be
performed as follows:
• Remove the identification plate (see figure 3 at chapter 3)
by releasing the holding screw lying on the bottom left
corner.
• Use a suitable screwdriver to press the switch down fully.
• Then turn the switch clockwise by 90°.
IMPORTANT
To deactivate the switch, push it down slightly and then turn
counterclockwise by 90°.
Figure 17 - Write-protection pushbutton
IMPORTANT
IMPORTANT
IMPORTANT - ALARM CURRENT