Emerson Process Management OXYMITTER 4000 instruction manual Calibration

Hazardous Area Oxymitter 4000

Instruction Manual

IB-106-340C Rev. 4.1 July 2004

3-3 RECOMMENDED CONFIGURATION a. 4-20 mA Signal Upon Critical Alarm

Rosemount recommends that the factory default be utilized. The 4-20 mA signal will go to the 3.5 mA level upon any critical alarm which will cause the O2 reading to be unusable. Customer can also select 21.6 mA as the failure setting if normal opera- tions cause O2 readings to go below the zero % O2 (3.5 mA) level.

If the O2 measurement is being utilized as part of an automatic control loop, the loop should be placed into manual upon this failure event or other appropriate action should be taken.

b. Calibration

Rosemount recommends utilizing an auto- calibration system, actuated by the “calibra- tion recommended” diagnostic. New O2 cells may operate for more than a year, but older cells may require recalibration every few weeks as they near the end of their life. This strategy ensures that the O2 reading is always accurate, and eliminates many unnecessary calibrations based on calendar days or weeks since previous calibration. When utilizing the SPS 4000 or IMPS 4000, consider wiring some or all associated alarm contacts.

1.CALIBRATION INITIATE. Contact from the control room to an SPS 4000 or IMPS 4000 (one per probe) provides the ability to manually initiate a calibra- tion at any time from the control room.

Note that calibrations can also be initiated from a HART handheld com- municator, from Asset Management Solutions software, or from the keypad on the Hazardos Area Oxymitter 4000.

2.IN CALIBRATION. One contact per probe provides notification to the con-

trol room that the “calibration recom- mended” diagnostic has initiated an

automatic calibration through the SPS 3 4000 or IMPS 4000. If the O2 signal is

being utilized in an automatic control loop, this contact should be utilized to place the control loop into manual during calibration.

3.CALIBRATION FAILED. One contact per probe from an SPS 4000 or IMPS 4000 to the control room for notification that the calibration procedure failed. Grouped with this alarm is an output from a pressure switch which indicates when the calibration gas bottles are empty.

4.4-20 mA SIGNAL DURING CALIBRATION. The 4-20 mA signal can be configured to respond normally during any calibration, or it can be con- figured to hold the last O2 value upon the initiation of calibration. The factory default is for the 4-20 mA signal to track (operate normally) throughout calibration. Holding the last O2 value may be useful if several probes are being averaged for the purpose of automatic control. Unless several probes are being averaged, always place control loops that are using the O2 signal into the manual mode prior to starting the calibration.

Rosemount Analytical Inc. A Division of Emerson Process Management Configuration with Keypad 3-5