Siemens 7MF4033 series, Руководство пользователя

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UMSITRPDS3-1 On-Line Operation
November 2010
6-21
Refer to the Online Configuration Map in Appendix A; the display of active data is indicated by a plus
sign (+) following the menu text.
6.4.2 Setting Zero and Full Scale
Zero and full scale can be set or adjusted from the HART Communicator. Following are the steps to set
zero and full scale. To adjust zero and full scale locally, refer to Section 6.2.2.
Zero and full scale can also be set or adjusted in the Detailed Setup menu. See the Online Configuration
Map in Appendix A for the path.
1. Apply a reference pressure that represents zero.
2. In the Online menu, press 3 Device Setup.
3. In the Device Setup menu, press 3 Basic Setup.
4. Press 4 in the Basic Setup menu and type a value for zero. Press the ENTER softkey to enter the zero
value and return to the Basic Setup menu or press ESC to return to the Basic Setup menu without
changing the zero value.
5. Apply a reference pressure representing full scale.
6. Press 5 in the Basic Setup menu and type a value for full scale. Press the ENTER softkey to enter the
full scale value and return to the Basic Setup menu or press ESC to return to the Basic Setup menu
without changing the zero value.
6.4.3 Blind Setting of Zero and Full Scale
Zero and full scale can be set without applying a reference pressure. Both values are freely selectable,
within sensor limits, as described above. The maximum turn down is 100:1, depending upon the
transmitter series and measuring range. Section 6.2.4 contains a discussion of the theoretical relationships
and an example.
6.4.4 Zero Adjustment for Position Correction
The zero error resulting from a non-vertical installation position (electrical enclosure directly over the
sensor) can be easily corrected. This procedure can be performed locally using the magnetic pushbuttons
or remotely using the HART Communicator. This procedure should be performed after transmitter
installation. If necessary, it can be performed on the test bench if the transmitter is exactly oriented as it
will be when installed.
IMPORTANT
To zero an absolute pressure transmitter, a vacuum must be applied! The zero
adjustment of a ventilated absolute pressure transmitter will cause an erroneous
zero to be set.
Note
The useful measuring range is reduced by the pre-pressure. For example, at a pre-
pressure of 40 inH
2
O (1.45 psi), the useful measuring range of a 14.5 psi
transmitter is reduced to 0 to 13.05 psi.