Emerson Process Management IM-106-340 Recommended Configuration, Calibration Handshake Signal

Oxymitter 4000

Instruction Manual

IM-106-340, Rev. 4.0 May 2006

Calibration Handshake Signal

Recommended Configuration

If using an optional IMPS 4000 or SPS 4001B, the logic I/O must be configured for calibration handshaking. Of the ten modes in Table 3-1,only modes 8 and 9 are configured for calibration handshaking. For an Oxymitter 4000 with an IMPS 4000 or an SPS 4001B, the factory sets the default to mode 8. In this mode, the logic I/O will be used to communicate between the Oxymitter 4000 and sequencer and to signal the sequencer when a CALIBRATION RECOMMENDATION indication occurs.

4-20 mA Signal Upon Critical Alarm

Rosemount Analytical 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 operations 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.

Calibration

Rosemount Analytical recommends utilizing an autocalibration system, actuated by the "calibration 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 4001B or IMPS 4000, consider wiring some or all associated alarm contacts.

1.CALIBRATION INITIATE. Contact from the control room to an SPS 4001B or IMPS 4000 (one per probe) provides the ability to manually initiate a calibration at any time from the control room. Note that calibrations can also be initiated from a HART handheld communicator, from Asset Management Solutions software, or from the keypad on the Oxymitter 4000.

2.IN CALIBRATION. One contact per probe provides notification to the control room that the "calibration recommended" diagnostic has initiated an automatic calibration through the SPS 4001B 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 4001B 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 configured to hold the last O2 value upon the initiation of calibration. The factory default is for the 4-20 mA signal to 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.

3-6