82
Safety Manual
00809-0200-5100, Rev GB
Dry-run Configuration
February 2017
Dry-run Configuration
4. Specify and configure the SIL Low Alarm Limit.
5. Disable the SIL High Alarm Limit:
SIL High Alarm Limit= Disabled (Type 0).
Warning! Ensure that appropriate measures are taken
to prevent overfill when the SIL High Alarm is disabled.
6. Set the SIL Amplitude Threshold = 2000 mV.
7. Adjust the SIL Calibration Distance as described in
Safety alarm setup / Step 2: Calibration of surface
on page 35.
Note! The product surface should be slightly below the
SIL Low Alarm Limit in the Tank. There are two reasons
for this:
a) calibration should be performed at this point in the
Tank to ensure highest accuracy at the SIL Low Alarm
Limit
b) to make sure that appropriate SIL Amplitude
Thresholds will be set based on the signal strength at
this point
8. Open the Tank Scan window to get an overview of
how much noise that exists in the Near Zone region,
i.e. the region below the SIL Used Hold Off Distance.
Tip! To open Tank Scan: right-click the 5900 icon
and choose Properties>Advanced
Configuration>Tank Scan.
9. Find the distance at which the amplitude is less than
200 mV in the region below the SIL Used Hold Off
Distance.
10. Add about one meter to the found distance and
enter this value as the SIL Near Zone Distance.
In case the amplitude is not above 200 mV
anywhere below the Hold Off region, add one
meter to the SIL Used Hold Off Distance and set this
distance as the SIL Near Zone Distance.
11. Configure the SIL Amplitude Threshold (Near
Zone) to at least 4 times the highest amplitude in
the Near Zone below the SIL Used Hold Off
Distance. It is recommended to set the SIL
Amplitude Threshold (Near Zone) to 2000 mV or
more even if 4 times the highest near zone
amplitude is less than that.
Note! It is important to convert distance values
presented in the Tank Scan window to the correct SIL
Distance values. This may be applicable for tanks with a
hand dip nozzle. Then the tank geometry configuration
may include a G Distance, i.e. the Tank Reference Point
and Gauge Reference Point are located at different
positions.
SIL Amplitude Threshold = 2000 mV
1. SIL Low Alarm Limit
2. Echo from product surface
3. 2. SIL Used Hold Off Distance
Distance
Amplitude
1
2
3
200 mV
+ 1 m
1. SIL Near Zone Distance
2. SIL Used Hold Off Distance
3. SIL Amplitude Threshold (Near Zone)
Distance
Amplitude
3
1
2
2000 mV
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