Troubleshooting / FAQs
8.3 Step 2: Performing a zero point adjustment
SITRANS F C MC2
32
Operating Instructions, 10/2009, A5E02154544-02
Resolving step 1 problems
1.
Make sure that the serial numbers on the sensor and the SENSORPROM® unit are
identical.
2.
Make sure that the sensor is installed as described in the installation chapter (Page 15) of
the sensor manual.
3.
Flush the pipe systems and the sensor for several minutes at maximum flow rate to
remove any air bubbles which may be present.
8.3
Step 2: Performing a zero point adjustment
The second step in the troubleshooting procedure is to zero point adjust the device. For
further information on zero point adjustment, see the commissioning chapter.
See also
Zero point adjustment (Page 25)
8.4
Step 3: Calculating the measurement error
Calculating the measurement error
The result of the zero point adjustment will show you whether the zero point was set under
good and stable conditions. The lower the value of ZERO SIGMA, the lower the measuring
error achievable.
For a well-installed flow meter, the ZERO SIGMA value is approximately the same order of
magnitude as the specified zero point error for the sensor size. The specified zero point
errors are indicated below
Table 8- 1
MC2 zero point error
Sensor size
Zero point error/ ZERO SIGMA value.
DN 20
0.6 kg/h
DN 25
0.96 kg/h
DN 40
2.85 kg/h
DN50
5.5 kg/h
DN65
11.4 kg/h
DN80
14,8 kg/h
DN100
25 kg/h
DN150
66 kg/h
Given the ZERO SIGMA value reading, it is possible to calculate the error which can be
expected for different flow rates, without performing time-consuming measurements. So
using this formula, one can assess if the application can be used as–is, or whether to use
more time improving the installation.