Check Reaction Time - Emerson Rosemount 625IR Manual

Operation
January 2024
4. Apply the gas from the gas cylinder with a gas flow between 0.5 and 1.0 liters/
5. Allow for gas reading to stabilize for at least one minute.
6. Start the data logger and perform logging for two minutes.
7. Calculate average gas value and standard deviation from the data logger and
3.3

Check reaction time

The gas detector response time is about 1 second, but in practical applications it takes
longer since the gas has to completely replace all the air filling the volume between the
lens and mirror.
To obtain a T90 response of less than 1.3 seconds, use the gas test kit or gas sample kit to
inject gas straight into the detector with a high gas flow (> 3 lpm).
If using a lower gas flow of about 1 lpm with the gas test kit, expect a T90 response time
of less than 4 seconds. For instructions on how to use the gas test kit or gas sample kit,
refer to
gas cylinder and detector so the time for the gas to flow through the tubes is not adding
significantly to the response time.
Procedure
1. Insert the gas sample kit.
2. Connect the tube from the gas cylinder to one of the nozzles on the gas sample kit.
3. Insert and lock the gas sample kit in place as illustrated in
4. Apply the gas from the cylinder with a flow between 0.5 and 1.1 liters/minute.
5. Allow the gas reading to stabilize for at least one minute.
6. Start the data logger and log for two minutes.
7. Calculate the average gas value and standard deviation from the data logger and
32
minute.
compare with the specifications of the detector for accuracy.
Perform a function check with the gas test kit
Figure 3-4: Insert gas sample kit
The time for the reading to stabilize depends on the gas flow and the length of the
tube.
compare it with the detector's accuracy specifications.
MS-00809-0100-3625
and use a short tube between the
Figure 3-4.
Manual
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