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Instruction Manual

Appendix AX Rev. 2.1

February 1998

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

World Class 3000

TERMINAL

STRIP

REFERENCE

GAS FITTING

P00006A

CALIBRATION

GAS FITTING

VENT

Figure A-6. Junction Box

A-4 JUNCTION BOX

The junction box, Figure A-6, is positioned at

the external end of the probe and contains a

terminal strip for electrical connections and fit-

tings for reference and calibration gases. Fit-

tings are for 0.250 inch stainless steel tubing.

The calibration fitting has a seal cap which must

remain in place except during calibration. A

tubing fitting is also supplied to be used with the

calibration gas supply during calibration.

If the calibration gas bottles will be permanently

hooked up to the probe, an optional check valve

is recommended to prevent condensation of flue

gas in the calibration lines.

During operation and calibration, reference gas

is supplied through the reference gas fitting to

the reference side of the cell. This gives the

system a known quantity of oxygen with which

to compare the oxygen level in the process gas.

Unlike the non-CENELEC World Class 3000

Probe, reference air must be used in conjunc-

tion with the CENELEC World Class 3000

probe.

During calibration, two gases of different known

oxygen concentrations are injected one at a

time through the calibration gas fitting. Stainless

steel tubing delivers this gas to the process side

of the cell. In a healthy cell, the difference in

oxygen pressure from the process side to the

reference side of the cell will cause a millivolt

output proportional to the difference in oxygen

levels. The electronics unit can use the two

millivolt outputs caused by the two calibration

gases for either automatic or semi-automatic

calibration.

Do not attempt to remove a process

gas sample through either gas fitting.

Hot gases from the process would

damage gas hoses in the probe head.

A-5 CABLE ASSEMBLY

Cable used to interconnect apparatus must

conform to the applicable codes of practice in

the country of installation (example: BS4345 in

Great Britain). Rosemount can supply a cable

(P/N 1U03066) which is fitted with EExd IIC

barrier glands. The installer should note that on

some earlier versions of the cable, the glands,

although EExd IIC approved, are not of the bar-

rier gland variety. These glands should not be

used. Rosemount can supply a gland kit for the

corresponding barrier gland (P/N 1U03066G07).

Each kit contains one pair of glands. The

Rosemount supplied cable is a 7 conductor

cable to connect the probe to the HPS 3000,

and to connect the HPS 3000 to the electronics

package. Standard length for this cable is 6 m

(20 ft), but lengths up to 45 m (150 ft) are avail-

able. The 7 conductors include 1 shielded pair

of wires for the cell millivolt signal, 1 shielded

pair of type K wires for the thermocouple, and 3

individual 16-gauge wires for the heater and for

ground. All metal shields are isolated at the

probe end and connect by drain wires to ground

at the electronics. The cable is suitable for use

in ambient temperatures up to 90°C (194°F).

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