Configuration and Calibration Guide HD0679 Rev 1.2.0 49
Chapter 6
Frequently Asked Questions
Q:
Hydro-Com doesn’t detect any sensors
A:
If there is more than one sensor connected on the RS485 network, ensure that each sensor
has a different address. 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 material source is used. However it is a good idea to take samples (see Introduction to
Material Calibration on Page 29) 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. Copy 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 Introduction to
Material Calibration on Page 29, 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:
For sand only (HP04 only)
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, you must 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 Analogue Output Setup on page 15 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 32 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.
Summary of Contents for Hydro-Mix
Page 4: ...4 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 6: ...6 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 8: ...8 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 10: ...10 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 14: ...Chapter 1 Introduction 14 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 28: ...Chapter 2 Configuration 28 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 42: ...Chapter 4 Best Practices 42 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 48: ...Chapter 5 Sensor Diagnostics 48 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
Page 52: ...Appendix A Document Cross Reference 52 Configuration and Calibration Guide HD0679 Rev 1 2 0 ...
