Emerson Rosemount Oxymitter 4000, Reference Manual, Page: 115 / 198

8 Troubleshoot
8.1 Overview
While the transmitter electronics provides a significant number of diagnostic alarms to
assist in troubleshooting potential problems, it is important to place these alarms in
perspective with respect to the instrument's operating principles.
When the zirconium oxide sensing cell is heated to its setpoint (1357 °F [736 °C]), the cell
will generate a voltage that represents the difference between the process O
2
percentage
and the reference O
2
percentage inside the probe (20.95 percent O
2
ambient air).
Test points ( Figure 8-1 ) are provided to read the raw millivolt value generated by the
thermocouple that controls both the cell temperature and the raw cell signal.
Figure 8-1: O
2
Sensor mV Readings vs. Percent O
2
at 1357 °F (736 °C) (Reference Air,
20.95 Percent O
2
)
Table 8-1: Logic I/O Configuration (as Set at HART/AMS or LOI)
O
2
% EMF (mV)
100 -34
20 1.0
15 7.25
10 16.1
Reference Manual Troubleshoot
00809-0100-4340 October 2019
Rosemount Oxymitter 4000 115