Damping Adjustment; Correction For High Line Pressure (Rosemount 1154Dh And 1154Hh Only) - Emerson Rosemount 1154DH Reference Manual

Rosemount 1154 Series H
Figure 3-4. Linearity and

Damping Adjustment.

Damping Adjustment
Correction For High Line
Pressure (Rosemount
1154DH and 1154HH
only)
3-6
Electronics Side of Transmitter
Housing (cover removed)
Damping electronics are available as an option. Transmitters with standard
electronics can be retrofitted with the adjustable damping feature by changing
out both the amplifier board (RMT P/N 01154-0021-0004) and the calibration
board (RMT P/N 01154-0023-0002).
The damping adjustment permits damping of rapid pressure variations by
adjusting the single-turn trim potentiometer located on the upper right-hand
side of the amplifier board (see Figure 3-4). The available settings, when
adjusted to the maximum position, provide time-constant values of at least 1.2
seconds for Range Code 4 and 0.8 seconds for Range Codes 5–9.
Transmitters with the electronic damping option are calibrated and shipped
with the adjustment set at the counterclockwise stop, which gives the
minimum time-constant.
To adjust the damping, turn the damping adjustment potentiometer until the
desired time-constant is obtained. It is best to set the damping to the shortest
possible time-constant. Since transmitter calibration is not affected by the
damping setting, you may adjust the damping with the transmitter installed on
the process.
The damping adjustment potentiometer has positive stops at both ends. Forcing the
potentiometer beyond the stops may cause permanent damage.
NOTE
If you remove either cover during the above procedures, replace the
O-ring and torque the cover per the instructions given in Section 5:
Maintenance and Troubleshooting of this manual. Spare cover
O-rings are supplied with each transmitter.
If a differential transmitter is calibrated with the low side at ambient pressure
but will be used at high line pressure, correct the span adjustment to
compensate for the effect of static pressure on the unit. If zero is elevated or
suppressed, also correct the zero adjustment. Correction factors, expressed
in percent of differential pressure input at end points per 1,000 psi static
pressure, are:
Reference Manual
00809-0100-4631, Rev BA
April 2007
Damping
Adjustment
(optional)
Linearity
Adjustment