Emerson 3000 manual World Class, Appendix A Rev. 3.6 July

Instruction Manual

Appendix A Rev. 3.6 July 1998

World Class 3000

terminal strip could act as additional ther- mocouple junctions. This could produce a voltage that would affect the thermocouple output signal.

Do not bend wires closer than 1/4 inch (6.4 mm) from end of ceramic rod. Dress wires so they do not touch sides of probe junction box.

l.Slide assembled probe junction box and in- ner probe assembly into probe tube. To align calibration gas tube with correspond- ing hole in backplate (A, B, Figure A-1), in- sert scriber through hole in backplate and into calibration gas tube. Secure with screws. Reinstall hoses and probe junction box cover.

m.Power up system. Monitor thermocouple output. It should stabilize at set point mV ±0.2 mV. Recalibrate probe per Instruction Bulletin applicable to your electronics package.

A-14 REPLACEMENT OF HEATER, V-STRUT AND BACKPLATE ASSEMBLY (INNER PROBE ASSEMBLY; INCLUDES CONTACT AND THERMOCOUPLE ASSEMBLY)

Use heat resistant gloves and clothing when removing probe junction box and inner probe assembly. Do not at- tempt to work on these components until they have cooled to room tem- perature. Probe components can be as hot as 800° (427°C). This can cause severe burns.

Disconnect and lock out power before working on any electrical components. There is voltage up to 115 Vac.

NOTE

This replacement may be done without removing the probe from the duct.

a.Disconnect and lock out power to electron- ics. Using heat resistant gloves and cloth- ing, remove probe cover. Squeezing tabs on hose clamps and remove hoses from probe junction box, Figure A-19.Remove four screws and lockwashers (7, 10, Figure A-22)that hold probe junction box and inner probe assembly to probe tube. Pull probe junction box and inner probe assembly free from probe tube. Set on bench and allow to cool to room temperature.

b.Disconnect cell extension wire (orange), thermocouple wire (red alumel), and ther- mocouple wire (yellow chromel) by cutting bomb tail connections from the terminal strip, Figure A-16.

c.Remove two screws, lockwashers, and flat washers that connect probe junction box to inner probe assembly. Remove and discard inner probe assembly (heater, V-strut, and backplate assembly). Replace with new in- ner probe assembly. Reinstall screws, lock- washers and flat washers.

d.Connect color coded wires to proper termi- nals as shown in Figure A-16.Rosemount recommends connecting the thermocouple wires directly to the terminal strip. This is because the junction of different metals at the wires and lugs and at the lugs and the terminal strip could act as additional ther- mocouple junctions. This could produce a voltage that would affect the thermocouple output signal.

Do not bend wires closer than 1/4 inch (6.4 mm) from end of ceramic rod. Dress wires so they do not touch sides of probe junction box.

A-22 Appendices Rosemount Analytical Inc. A Division of Emerson Process Management