Emerson Rosemount Oxymitter 4000, Reference Manual, Page: 81 / 198

WARNING
Typically, the probe's sensing cell, in direct contact with the process gases, is
heated to approximately 1357 °F (736 °C).
The external temperature of the probe body may exceed 842 °F (450 °C). If
operating conditions also contain high oxygen levels and combustible gases, the
transmitter may self-ignite.
3. Position 3 determines the output at start-up or at an alarm. The settings are 3.5 mA
or 21.6 mA. The factory setting is 3.5 mA. At start-up, the analog output is 3.5 mA
or 21.6 mA.
4. You can use position 4 to set the heater for 115 or 220 Vac operation. This switch is
functional only when the software is set for manual voltage selection (Auto Tune =
No). Otherwise, the internal electronics auto detect the input line voltage and set
the heater voltage accordingly (Auto Tune = Yes).
4.4.3 Read O
2
concentration
Once the cell is up to operating the temperature, you can read the O
2
percentage.
Procedure
1. To access TP5 and TP6 under the LOI module ( Figure 4-2 ), power down the
transmitter and remove the LOI module.
2. Attach alligator leads from a multimeter across TP5 and TP6.
3. Install the LOI module and power up the transmitter. Allow time for the cell to reach
operating temperature.
You can now monitor the calibration and process gases. When you have initiated a
calibration, the value at TP5 and TP6 is the % O
2
seen by the cell. Oxygen levels, as seen on
the multimeter, are:
• 8.0% O
2
= 8.0 Vdc
• 0.4% O
2
= 0.4 Vdc
You can also read the O
2
concentration on:
• HART
®
/AMS
WARNING
The HART option is not protected by energy limiting barriers.
Do not interface with the HART option from within the hazardous area.
Route the 4-20 mA cables and make the connections outside the hazardous area.
This is the case even when using the intrinsically safe version of the handheld
communicator.
• Rosemount
™
751, loop-driven LCD display
Reference Manual Configure transmitter with LOI
00809-0100-4340 October 2019
Rosemount Oxymitter 4000 81