Environment Shield - Emerson Rosemount 625IR Manual

Manual
MS-00809-0100-3625
1.5.2 Performing loop test
The Rosemount 625IR can perform a loop test through the HART
The loop test allows you to manually set the analog signal output to a selected value for a
limited time.
1.6

Environment shield

Dirt, dust, snow, and liquids gathered on the lens and mirror will reduce the amount of
infrared (IR) light used for detecting gas.
A clean detector should have about 100 percent signal strength. Over time, the optics
will get dirty and the signal strength will drop. If the signal goes below 70 percent, the
detector gives an
optics. If the optics are not cleaned, more dirt will accumulate on the optics. If signal
strength drops below 55 percent, the detector will go into
dirt accumulates on the optics depends on how dirty the environment is.
Water splash, such as from fire extinguishing systems, can also block the optics. Also, in
some cases insects and other objects can block the optics. To reduce the likelihood of
water or insects getting into the optical path, use an environment shield. The environment
shield can also extend the time before dirt and similar substances accumulate on
the optics, which can increase the cleaning intervals.
environment shield offered.
Table 1-4: Environment shield
Type
Environment shield
For the fastest response time, use the 625IR without the environment shield. In most
cases, Emerson recommends using the environment shield, since it makes the detector
more robust against water and dirt. Even with the environment shield, the detector has a
very fast response time.
The environment shield for the 625IR consists of one compact unit fitting into the gas
sensing section as illustrated in
for optimum performance of the detector.
slots into the sensing section of the 625IR. Before inserting the environment shield, visually
inspect the detector to verify that it is free from dirt and blocking substances. Ensure that
the shield is inserted all the way.
Rosemount 625IR
EARLY CLEAN OPTICS
Application examples
The standard environment shield
comes with the Rosemount 625IR. It
gives good protection from ingress of
water and other contaminants.
Figure 1-15. Emerson has designed the environment shield
or Modbus
®
warning. If you see this warning, clean the
BEAM BLOCK FAULT
Table 1-4 is an overview of the
Performance effect
Gas response time is specified with the
environment shield in place. Without
the environment shield, the response
time is slightly faster.
Figure 1-14 shows how the environment shield
Installation
January 2024
interface.
®
. How fast
19