Emerson Rosemount 936, Reference Manual

Page: 20 / 76

• Low voltage fault (1 mA output)
In this situation, detection is disabled due to low voltage being supplied to the
detector. The detector returns to proper operation only when proper voltage level is
restored.
• Fault 2 (1 mA output)
In this situation, the detection is disabled due to an electrical/software operational
failure or a central device (memory or processor) fault. Such a fault causes the detector
to cease operation. If there is a fault in the 0-20 mA loop, the output is 0 mA.
3.1.4 Zero calibration mode (1 mA output)
This mode zeroes the base level from which the detector reads gas.
Only do this when:
• No gases are present.
• There is a clear path between the source and the detector.
• Weather conditions are clear.
Use the Field Communicator of host software on your personal computer (PC) to zero
calibrate after installation, re-alignment, and window cleaning. In parallel, while the
detector is connected to the Field Communicator, the magnetic mode selector can be
used for zero calibration.
Related information
Zero calibrate
3.2 Visual indicators
One three color light-emitting diode (LED) indicator is located in the back side of the
detector/source and can be seen through the back cover window.
See Figure 2-1 and Figure 2-2 .
The detector statuses are listed in Table 3-1 .
Table 3-1: Detector LED indications
Detector status LED color LED mode
Fault Yellow 4 Hz - flashing
Alignment / Standby Yellow 1 Hz - flashing
Zero calibration Yellow Constant
Normal Green 1 Hz - flashing
Warning Red 2 Hz - flashing
Alarm Red Constant
The source statuses are listed in Table 3-2 .
Operating modes Reference Manual
October 2021 00809-0100-4036
20 Emerson.com/Rosemount