Hydro-Probe XT User Guide HD0538 Rev: 1.6.0 61
Chapter 9
Frequently asked questions
Q:
Hydro-Com doesn’t detect any sensor when I press search.
A:
If there is more than one sensor connected on the RS485 network, ensure that each sensor is
addressed differently. Ensure the sensor is correctly connected, that it is powered from a
suitable 15-30Vdc source and the RS485 wires are connected through a suitable RS232-485
or USB-RS485 converter to the PC. On Hydro-Com ensure the correct COM port is selected.
Q:
How often should I calibrate the sensor?
A:
Recalibration is not necessary unless the gradation of the material changes significantly or a
new source is used. However it is a good idea to take samples (see Calibration procedure on
Page 47) regularly on site to confirm the calibration is still valid and accurate. Put this data in
a list and compare them with the results of the sensor. If the points lie near to or on the
calibration line then the calibration is still good. If there is a continuous difference you have to
recalibrate.
Q:
If I have to replace the sensor do I have to calibrate my new sensor?
A:
Normally no, assuming the sensor is mounted in exactly the same position. Write the
calibration data for the material to the new sensor and the moisture readings will be the same.
It would be wise to verify the calibration by taking a sample as shown in Calibration procedure
on Page 47, and checking this calibration point. If it lies near to or on the line then the
calibration is still good.
Q:
What should I do if there is little variation of moisture in my material on the day I calibrate?
A:
If you have dried different samples and there is little variation in moisture (1-2%), then settle
for one good calibration point by averaging the Unscaled readings and oven dried moistures.
Hydro-Com will allow you to produce a valid calibration until further points can be made.
When the moisture changes by at least 2% then sample again and enhance the calibration by
adding more points. .
Q:
If I change the type of material I am using, do I need to recalibrate?
A:
Yes, it is advisable to calibrate to each type of material.
Q:
Which output variable should I use?
A:
This depends on whether the calibration is stored in the sensor or the batch controller, and if
the digital input is used for batch averaging. Refer to Figure 32 for more information.
Q:
There seems to be a scatter in the points I have made in my calibration, is this a problem and
is there something I can do to improve the calibration result?
A:
If you have a scattering of points through which you are trying to fit a line, then there is a
problem with your sampling technique. Ensure the sensor is mounted properly in the flow. If
the sensor position is correct and the sampling is done as explained on Page 47 then this
should not happen. Use an ‘Average Unscaled’ value for your calibration. The averaging
period can be set either with the ‘Average/Hold’ input, or using ‘Remote Averaging’. See
Hydro-Com User Guide (HD0682) for more information.
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Страница 14: ...Chapter 1 Introduction 14 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 42: ...Chapter 4 Configuration 42 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 52: ...Chapter 6 Optimising Sensor and Process Performance 52 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 58: ...Chapter 7 Sensor diagnostics 58 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 60: ...Chapter 8 Technical specification 60 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 66: ...Appendix B Document Cross Reference 66 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
