Emerson Process Management IM-106-340 instruction manual Recommended Configuration

Oxymitter 4000

Instruction Manual

IM-106-340, Rev. 4.0 May 2006

Recommended	Recommended Configuration
Configuration	4-20 mA Signal
	The 4-20 mA signal is linear, and can be ranged by the user for O2 range from
	0-40% O2. It should be noted that the 4-20 mA signal will go to one of several
	default values under certain conditions:
	Condition	Default	Option
	In calibration	4-20 mA signal responds	4-20 mA signal holds last value during
		normally to cal gas	cal. (recommended only if several O2
			probes are being averaged together)
	O2 over preset	4-20 mA signal defaults to	none
	range	20.5 mA
	Critical alarm	4-20 mA signal defaults to	4-20 mA signal dfaults to 21.1 mA
		3.5 mA
	Dead Instrument	4-20 mA signal goes to	none
		zero mA

It is very important that the control system be configured to recognize these various signal levels, and operators be briefed as to their meaning.

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 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.

4-6