Emerson Rosemount 935, Reference Manual

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5.6 Functional check
Emerson calibrated the system at the factory for your specific gas or vapor detection
requirements. Use the check filters included in the commissioning kit according to the
corresponding calibrating gas to validate correct installation.
The functional check filter is a convenient operational check used to confirm that the
response has not changed from previous readings. The filter is not used for calibration,
which is unnecessary, nor does it equate to a particular quantity of gas.
Prerequisites
Note
This functional verification procedure is for a standard 0-20 mA output.
Prior to starting the functional check, verify that the power to the detector is on and that
the current of the 0-20 mA channel is stable. Record the reading.
Procedure
1. Position the functional check filter in front of the detector. Center the functional
check filter's window over the viewing window of the detector.
The check filters are provided in the commissioning kit.
Figure 5-5: Detector with functional check filter installed
2. Wait twenty seconds.
3. Read the 0-20 mA current. Determine the difference between the reading taken
with and without the functional check filter.
The difference is the 0-20 mA current variance.
4. Record the 0-20 mA current variance in the maintenance log book.
Postrequisites
If the variance is more than a 30 percent change when compared to the previous check
(see delivery form), repeat the alignment.
Reference Manual Operation
00809-0100-4035 May 2022
Rosemount 935 45