Emerson Process Management OXYMITTER 4000 Hazardous Area Oxymitter, Imps, Remote Mounted, Sps

Hazardous Area Oxymitter 4000

Instruction Manual

IB-106-340C Rev. 4.1

July 2004

1

When the cell is at operating temperature and there are unequal oxygen concentra- tions across the cell, oxygen ions will travel from the high oxygen partial pressure side to the low oxygen partial pressure side of the cell. The resulting logarithmic output voltage is approximately 50 mV per decade. The output is proportional to the inverse logarithm of the oxygen concentration. Therefore, the output signal increases as the oxygen concentration of the sample gas decreases. This characteristic enables the Hazardous Area Oxymitter 4000 to provide exceptional sensitivity at low oxygen concentrations.

The Hazardous Area Oxymitter 4000 meas- ures net oxygen concentration in the pres- ence of all the products of combustion, including water vapor. Therefore, it may be considered an analysis on a “wet” basis. In comparison with older methods, such as the portable apparatus, which provides an analysis on a “dry” gas basis, the “wet” analysis will, in general, indicate a lower percentage of oxygen. The difference will be proportional to the water content of the sampled gas stream.

HAZARDOUS AREA

OXYMITTER 4000

IMPS 4000
(1 TO 4 PROBES)
(MUST BE INSTALLED	REMOTE MOUNTED
IN A SAFE AREA	SPS 4000
OR BE X- OR Z-PURGED	(1 PROBE)
BY THE CUSTOMER)
	(MUST BE INSTALLED
	IN A SAFE AREA)

26310002

c.System Configuration

Hazardous Area Oxymitter 4000 units are available in three length options, giving the user the flexibility to use an in situ penetra- tion appropriate to the size of the stack or duct. The options on length are 457 mm (18 in.), 0.91 m (3 ft), and 1.83 m (6 ft).

The electronics control probe temperatures and provide an isolated output, 4-20 mA, that is proportional to the measured oxygen concentration. The power supply can accept voltages of 90-250 VAC and 48/62 Hz; no setup procedures are required. The oxygen sensing cell is maintained at a constant temperature by modulating the duty cycle of the probe heater portion of the electronics. The electronics accepts millivolt signals generated by the sensing cell and produces the outputs to be used by remotely con- nected devices. The output is an isolated 4-20 mA linearized current.

Figure 1-2. Hazardous Area Oxymitter 4000

Autocalibration System Options

The Oxymitter 4000 transmitter is available with an integral or remote electronics pack- age. Two calibration gas sequencers are available to the Hazardous Area Oxymitter 4000, but they must be installed in a non- hazardous, explosive-free environment: the IMPS 4000 and the SPS 4000 (Figure 1-2).

Systems with multiprobe applications may employ an optional IMPS 4000 Intelligent Multiprobe Test Gas Sequencer. The IMPS 4000 provides automatic calibration gas sequencing for up to four Hazardous Area Oxymitter 4000 units and accommodates autocalibrations based on the CALIBRA- TION RECOMMENDED signal from the Hazardous Area Oxymitter 4000, a timed interval set up in HART or the IMPS 4000, or whenever a calibration request is initiated.

Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 1-3