Visual Indicators - Emerson Rosemount 935 Reference Manual

Open path combustible gas detector

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Reference manual (56 pages)

Quick start manual (40 pages)

Quick start manual (40 pages)

Table Of Contents

Table of Contents

Operating modes

May 2022

If this occurs, it is due to blockage, very low signal, partial obscuration, or full beam

block. In this situation, detection is no longer possible. The detector's proper operation

can be restored (auto reset) during operation if the condition causing the problem is

removed or resolved. This mode occurs after a delay of 60 seconds from the moment

of the fault. This delay is important to eliminate momentary obscuration due to

passing through the beam.

•

Fault 2 (1 mA output) - critical

In this case, the detector is disabled due to electrical/software operational failure,

central device (memory or processor) fault, or low voltage. This 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 a field communicator or host software on your personal computer (PC) to zero

calibrate after installation, re-alignment, and window cleaning. While the device is

connected to the field communicator, you can also use the magnetic mode selector for

zero calibration.

Related information

Zero calibrate

3.2