Emerson 1154 manual Damping Adjustment, Rosemount, Reference Manual, Maximum Allowable Span

Reference Manual

00809-0100-4514, Rev BA January 2008

Rosemount 1154

Figure 3-4. Linearity and Damping Adjustment.

Damping Adjustment

1.Apply mid-range pressure and note the error between theoretical and actual output signal.

2.Apply full-scale pressure. Multiply the error noted in step 1 by six and by the rangedown factor:

Maximum Allowable Span

Rangedown Factor = --------------------------------------------------------------------

Calibrated Span

3.Add the result to the full-scale output for negative errors, or subtract the result from the full-scale output for positive errors by adjusting the linearity trimmer (see Figure 3-4). Example: At

4-to-1 rangedown the midscale point is low by 0.05 mA. Therefore, adjust the “Linearity” trimmer until full-scale output increases by (0.05 mA ￿ 6 ￿ 4) = 1.2 mA.

4.Readjust zero and span.

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. Spare cover O-rings are supplied with each transmitter.

Damping

Adjustment

(Optional)

Linearity

Adjustment

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).

3-5