Emerson Rosemount 1152 Alphaline, Reference Manual

Page: 22 / 68

Reference Manual
00809-0100-4235, Rev BA
April 2007
Rosemount 1152
3-2
Span Adjustment (A and
D Output)
The span on any Rosemount 1152 Transmitter is continuously adjustable to
allow calibration anywhere between maximum span and
1 /
6
of maximum span.
For example, the span on a Range Code 4 transmitter can be continuously
adjusted between 0–25 and 0–150 inH
2
O.
Zero Adjustment (A and
D Output)
Zero adjustments are limited as follows:
Rosemount 1152DP, Ranges 3, 4, and 5: 150 percent of calibrated span
suppression or elevation.
Rosemount 1152DP, Ranges 6, 7, and 8: 50 percent of calibrated span
suppression or elevation.
Rosemount 1152HP, Ranges 4 and 5: 150 percent of calibrated span
suppression or elevation.
Rosemount 1152HP, Ranges 6 and 7: 50 percent of calibrated span
suppression or elevation.
Rosemount 1152GP, all ranges: 100 percent of calibrated span suppression;
to 0.5 psia elevation for compound ranges.
Rosemount 1152AP, all ranges: 100 percent of calibrated span suppression.
The transmitter may be calibrated to cross zero (e.g., –25 to 25 inH
2
O), but
this may result in a slight loss of linearity. A further limitation on zero
adjustment is that the top of the span may not exceed the upper range limit.
Calibration Procedure—
Zero and Span
Adjustment (A and D
Output)
NOTE
The Rosemount 1152 Pressure Transmitter contains electronic circuit boards
which may be static sensitive.
NOTE
Covers need not be removed for zero and span adjustment.
The zero adjustment has very little effect on the span. Span adjustment may
have a slight effect on zero and has a noticeable effect when zero is elevated
or suppressed because the span is rotated about a point on the zero
differential. The following example for a Rosemount 1152DP, Range 4, shows
the proper sequence for changing a 25 to 125 inH
2
O range (suppressed zero
of 25 inH
2
O, span of 100 inH
2
O) to a range of –75 to
–25 inH
2
O (elevated zero of 75 inH
2
O, span of 50 inH
2
O).
1. Turn the zero adjustment to bring the range from 25–125 inH
2
O to 0–
100 inH
2
O.
2. Turn the span adjustment to bring the range from 0–100 inH
2
O to 0–
50 inH
2
O.
3. Turn the zero adjustment to bring the range from 0–50 inH
2
O to
–75 to –25 inH
2
O.
4. Recheck full scale and zero and adjust if necessary.
NOTE
There is some mechanical backlash in the zero and span adjustments, so
there will be a dead band when direction of adjustment is changed. The
simplest correction, if the desired setting is overshot, is purposely
overshooting a larger amount before reversing the direction of adjustment.