Emerson 3000 Calibration, World Class, Instruction Manual, 4-1ANALOG OUTPUT CALIBRATION

World Class 3000

Instruction Manual

IB-106-300NH Rev. 4.3 May 2005

SECTION 4 CALIBRATION

4-1 ANALOG OUTPUT CALIBRATION

For the analog output to perform within the pub- lished specifications, it must be manually cali- brated. The only equipment needed to perform the calibration is a voltage or current meter, de- pending on which mode of operation is to be calibrated. Prior to manual calibration, remove the IFT from any control loops it may be in.

Prior to manual calibration, the IFT should be removed from any auto- matic control loops. Failure to remove the IFT from control loops prior to calibration may result in faulty equip- ment performance.

Once initiated from the Setup - Analog Outputs menu, the calibration procedure is self guiding.

4-2 SYSTEM CALIBRATION

a.Overview

The primary purpose of an oxygen analyzer is to give an accurate representation of the percentage of O2 in the gas stream. The system should be calibrated periodically to maintain an accuracy which may otherwise be reduced over time due to cell aging. A calibration record sheet is provided at the end of this section to track cell performance.

A requirement for calibration is a set of two accurate calibration gases spanning the oxygen range of most interest. For example, 0.4% and 8% for a 0-10% oxygen range.

Under normal conditions the probe should not need frequent calibration. Because cali- bration is necessary, the system can be equipped with the optional MPS 3000 Multi- probe Calibration Gas Sequencer for fully automatic calibration at regular intervals. Without an MPS, the probes must be cali- brated manually (semiautomatically).

b.Probe Calibration

1.Previous Calibration Constants Functionality

There are three sets of registers used to store calibration constants. These are: Latest Calibration, Previous Cali- bration, and Calculation. Only the val- ues in the Calculation register are used to calculate the oxygen value for dis- play and representation on the analog output signal. These values may be changed in two ways.

(a)The operator may change the val- ues through the SETUP menu. The operator may adjust the slope and constant individually, or reset both to the values calculated during the last good calibration. To reset the values, move the cursor to RESET SLOPE & CONST and push

ENTER.

(b)The IFT will automatically change the values after each calibration as follows:

The values in the Latest Calibra- tion registers are updated after every complete calibration, even if the calibration is not successful. If the calibration is successful, the values in the Latest Calibration registers are copied into the Previ- ous Calibration registers. This is accomplished prior to the update of the Latest Calibration registers. The new slope and constant are copied into the Calculation register.

If the calibration fails, the Previous Calibration registers retain their existing values, while the Latest Calibration registers record the values of the failed calibration. The Calculation register is not updated when the calibration fails.

Rosemount Analytical Inc. A Division of Emerson Process Management Calibration 4-1