Hydronix Hydro-Probe Use and care manual

Hydronix Moisture Sensor
Configuration and Calibration
Guide
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Revision:
Revision date:
HD0679
1.2.0
October 2015

2Configuration and Calibration Guide HD0679 Rev 1.2.0
Copyright
Neither the whole or any part of the information contained in nor the product described in this documentation may
be adapted or reproduced in any material form except with the prior written approval of Hydronix Limited,
hereinafter referred to as Hydronix.
© 2015
Hydronix Limited
7 Riverside Business Centre
Walnut Tree Close
Guildford
Surrey GU1 4UG
United Kingdom
All rights reserved
CUSTOMER RESPONSIBILITY
The customer in applying the product described in this documentation accepts that the product is a
programmable electronic system which is inherently complex and which may not be completely free of errors. In
doing so the customer therefore undertakes responsibility to ensure that the product is properly installed
commissioned operated and maintained by competent and suitably trained persons and in accordance with any
instructions or safety precautions made available or good engineering practice and to thoroughly verify the use of
the product in the particular application.
ERRORS IN DOCUMENTATION
The product described in this documentation is subject to continuous development and improvement. All
information of a technical nature and particulars of the product and its use including the information and
particulars contained in this documentation are given by Hydronix in good faith.
Hydronix welcomes comments and suggestions relating to the product and this documentation
ACKNOWLEDGEMENTS
Hydronix, Hydro-Probe, Hydro-Mix, Hydro-Skid, Hydro-View and Hydro-Control are Registered Trade Marks of
Hydronix Limited

Configuration and Calibration Guide HD0679 Rev 1.2.0 3
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Guildford
Surrey
GU1 4UG
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Fax: [phone]
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4Configuration and Calibration Guide HD0679 Rev 1.2.0

Configuration and Calibration Guide HD0679 Rev 1.2.0 5
Revision history
Revision No
Date
Description of Change
1.0.0
Feb 2015
First Release
1.1.0
July 2015
Multi-Mode Calibration Section Added
1.2.0
October
2015
Process for calibrating a sensor in a mixer added

6Configuration and Calibration Guide HD0679 Rev 1.2.0

Configuration and Calibration Guide HD0679 Rev 1.2.0 7
Table of Contents
Chapter 1 Introduction...........................................................................................................................11
1Introduction.................................................................................................................................11
Chapter 2 Configuration........................................................................................................................15
1Configuring the Sensor...............................................................................................................15
2Analogue Output Setup..............................................................................................................15
3Digital Inputs/Output Setup ........................................................................................................17
4Averaging Parameters................................................................................................................19
5Filtering.......................................................................................................................................20
6Typical Moisture Trace from a Hydronix Moisture Sensor in Flowing Material..........................21
7Filtering the Signal When Used in a Mixer Application..............................................................22
9Outputting the Sensor Data........................................................................................................26
Chapter 3 Sensor Integration and Material Calibration.........................................................................29
1Sensor Integration......................................................................................................................29
2Introduction to Material Calibration ............................................................................................29
3SSD Coefficient and SSD Moisture Content..............................................................................31
4Storing Calibration Data.............................................................................................................31
5Calibration Procedure for Flowing Material (Linear) ..................................................................32
6Good/Bad Calibration.................................................................................................................34
7Quadratic Calibration..................................................................................................................35
8Calibrating a sensor in a mixer...................................................................................................36
9Brix Calibration...........................................................................................................................38
Chapter 4 Best Practices ......................................................................................................................41
1General to all Applications .........................................................................................................41
Chapter 5 Sensor Diagnostics ..............................................................................................................43
1Sensor Diagnostics ....................................................................................................................43
Chapter 6 Frequently Asked Questions................................................................................................49
Appendix A Document Cross Reference..............................................................................................51
1Document Cross Reference.......................................................................................................51

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Configuration and Calibration Guide HD0679 Rev 1.2.0 9
Table of Figures
Figure 1: Connecting the Sensor (Overview)........................................................................................13
Figure 2: Guidance for Setting Output Variable....................................................................................15
Figure 3: Raw and Filter Include Sensor Output...................................................................................21
Figure 4: Raw Unscaled Moisture Trace in Flowing Material ...............................................................21
Figure 5: Graph showing the Filtered Signal.........................................................................................21
Figure 6: Typical Moisture Curve..........................................................................................................22
Figure 7: Graph showing Raw Signal during Mix Cycle........................................................................22
Figure 8: Filtering the RAW Unscaled Signal (1)..................................................................................23
Figure 9: Filtering the RAW Signal (2)..................................................................................................23
Figure 10: Relationship of Unscaled Values to Moisture......................................................................25
Figure 11: Data arrangement in the sensor..........................................................................................26
Figure 12: None specified Output Selection .........................................................................................27
Figure 13: Legacy Output Selection......................................................................................................27
Figure 14: Calibrations for 3 Different Materials ...................................................................................29
Figure 15: Typical Calibration Results ..................................................................................................30
Figure 16: Calibration inside the Sensor...............................................................................................31
Figure 17 - Calibration inside the Control System ................................................................................32
Figure 18 - Example of Good Material Calibration................................................................................34
Figure 19 - Examples of Poor Material Calibration Points....................................................................35
Figure 20: Example of a Good Quadratic Calibration...........................................................................36
Figure 21: Example of a Bad Quadratic Calibration .............................................................................36
Figure 22: Example of a Good Brix Calibration.....................................................................................39
Figure 23: Example of a Bad Brix Calibration.......................................................................................39

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Configuration and Calibration Guide HD0679 Rev 1.2.0 11
Chapter 1 Introduction
1 Introduction
This Configuration and Calibration Guide is valid for the following Hydronix sensors only:
Hydro-Probe (Model number HP04 onwards)
Hydro-Probe XT (Model number XT02 onwards)
Hydro-Probe Orbiter (Model number ORB3 onwards)
Hydro-Probe SE (Model number SE03 onwards)
Hydro-Mix (Model number HM08 onwards)
User guides for other model numbers are available from www.hydronix.com
Hydro-Probe / XT Hydro-Mix
Hydro-Probe Orbiter
Hydro-Probe SE

Chapter 1 Introduction
12 Configuration and Calibration Guide HD0679 Rev 1.2.0
Hydronix Microwave Moisture sensors use high speed digital signal processing filters and
advanced measurement techniques. This gives a signal which is linear with the change in
moisture in the material being measured. The sensor must be installed into a material flow and
will then give an online output of the moisture change in the material.
Typical applications include moisture measurement in Sand, Aggregates, Concrete, Biomass
materials, Grain, Animal feed and Agricultural materials.
The sensors are designed to operate in various applications and have been created to allow the
material to flow past the sensor. The following are examples of typical applications.
•Bins / Hoppers / Silos
•Conveyors
•Vibratory Feeders
•Mixers
The sensor has two analogue outputs which are fully configurable and can be internally
calibrated to give a direct moisture output which is compatible with any control system.
Two digital inputs are available which can control the internal averaging function. This allows the
sensor measurement, which is taken at 25 times per second, to enable rapid detection of any
changes in moisture content to be averaged. This facilitates easier use in the control system.
One of the digital inputs can be configured to provide a digital output which can provide an alarm
signal in the event of a low or high reading. This can be used to signal a high moisture alarm or
alternatively to signal an operator that a storage bin needs to be refilled.
Hydronix sensors are specially designed using suitable materials to provide many years of
reliable service even in the most arduous conditions. However, as with other sensitive electronic
devices, care should be taken not to subject the sensor to unnecessary impact damage.
Particular care should be paid to the ceramic faceplate which, whilst being extremely resistant to
abrasion, is brittle and may be damaged if hit directly.
CAUTION – NEVER HIT THE CERAMIC
Care should be taken to ensure that the sensor has been correctly installed
and in such a manner to ensure representative sampling of the material
concerned. It is essential that the sensor is installed in a location where the
ceramic faceplate is fully inserted into the main flow of the material. It must not
be installed in motionless material nor where material can build-up on the
sensor.
All Hydronix sensors are pre-calibrated in the factory so that they read 0 when in air and 100
when submerged in water. This is called the ‘Unscaled Reading’ and is the base value used
when calibrating a sensor to the material being measured. This standardises each sensor, so if
a sensor is changed then there is no need to redo the material calibration.
After installation the sensor should be calibrated to the material (see Chapter 3 for more details).
The sensor can be setup in two ways:
•Calibration inside sensor: Sensor is calibrated internally and outputs true moisture.
•Calibration inside control system: Sensor outputs an unscaled reading which is
proportional to moisture. Calibration data inside the control system converts this to true
moisture

Introduction Chapter 1
Configuration and Calibration Guide HD0679 Rev 1.2.0 13
2 Measuring Techniques
The sensor uses the unique Hydronix digital microwave technique that provides a more sensitive
measurement compared to analogue techniques. This technique facilitates a choice of
measurement modes (not available in all sensors, see relevant sensors installation guide for
technical specifications). The default mode is F Mode which is suitable for all material but
particularly sand and aggregates. For more information about which mode to select please
contact Hydronix: [e-mail]
3 Sensor Connection and Configuration
The moisture sensor may be remotely configured using a digital serial connection and a PC
running Hydro-Com sensor configuration and calibration software. For communication with a PC,
Hydronix supply RS232-485 converters or a USB Sensor Interface Module (See User Guide
HD0303)
Note: All references to Hydro-Com in this user guide refer to software version 2.0.0 and
higher. The sensor can be configured using older versions of Hydro-Com however
some features will not be available. See the relevant Hydro-Com user guide for more
details.
There are two basic configurations for connecting the sensor to a batch control system:
•Analogue output – A DC output is configurable to:
•4-20 mA
•0-20 mA
•0-10 V output can be achieved using the 500 Ohm resistor supplied with the sensor
cable.
•Digital – an RS485 serial interface permits direct exchange of data and control
information between the sensor and the plant control computer. USB and Ethernet
adapter options are also available
The sensor can be configured to output a linear value of between 0-100 unscaled units with the
material calibration being performed in the control system. Alternatively it is also possible to
internally calibrate the sensor to output a real moisture value.
Power supply
+15V-
30 Vdc, 1A min.
2 x Analogue output
0-20mA, 4-20mA, 0-10V
Digital inputs/Output
RS485 serial
communications
Sensor
Figure 1: Connecting the Sensor (Overview)

Chapter 1 Introduction
14 Configuration and Calibration Guide HD0679 Rev 1.2.0

Configuration and Calibration Guide HD0679 Rev 1.2.0 15
Chapter 2 Configuration
1 Configuring the Sensor
The Hydronix microwave moisture sensor has a number of internal parameters which can be
used to optimise the sensor for a given application. These settings are available to view and
change using the Hydro-Com software. Information for all settings can be found in the Hydro-
Com User Guide (Hydro-Com User Guide HD0682).
Both the Hydro-Com software and the Hydro-Com user guide can be downloaded free of charge
from www.hydronix.com.
All Hydronix sensors operate in the same way and use the same configuration parameters.
However, not all the functions are used in every sensor application. (Averaging parameters, for
example, are typically used for batch processes).
2 Analogue Output Setup
The working range of the two current loop outputs can be configured for the equipment it is
connected to, for example a PLC may require 4 – 20 mA or 0 – 10V DC etc. The outputs can
also be configured to represent different readings generated by the sensor e.g. moisture or
temperature.
Figure 2 may be used to assist in selecting the correct analogue output variable for a given
system.
Figure 2: Guidance for Setting Output Variable
2.1 Output Type
This defines the type of the analogue outputs and has three options:
•0 – 20mA: This is the factory default. The addition of an external 500 Ohm precision
resistor converts the 0-20mA to 0 – 10V DC.
•4 – 20mA.

Chapter 2 Configuration
16 Configuration and Calibration Guide HD0679 Rev 1.2.0
2.2 Output Variable 1 and 2
These define which sensor readings the analogue output will represent and has 10 options.
2.2.1 Raw Unscaled
This is the raw unfiltered unscaled variable. A Raw Unscaled value of 0 is the reading in
air and 100 would relate to a reading in water. As no filtering is applied to this variable it
should not be used for process control. This output can be used for logging during initial
sensor installation.
2.2.2 Raw Unscaled 2
If set this will output the alternative measurement mode as configured for the sensor (see
Chapter 2 Section 8 for more information about alternative measurement modes). No
filtering will be applied.
Note: This mode is not available in all sensors please see the technical
specification in the relevant installation guide for more details.
2.2.3 Filtered Unscaled
Filtered Unscaled represents a reading which is proportional to moisture and ranges from
0 – 100. An unscaled value of 0 is the reading in air and 100 would relate to a reading in
water.
2.2.4 Filtered Unscaled 2
The Filtered Unscaled uses the second measurement mode configured in the sensor.
Note: This mode is not available in all sensors. Please see the technical
specification in the relevant installation guide for more details.
2.2.5 Average Unscaled
This is the ‘Raw Unscaled’ variable processed for batch averaging using the averaging
parameters. To obtain an average reading, the digital input must be configured to
‘Average/Hold’. When this digital input is activated, the Raw Unscaled readings are
averaged. When the digital input is low, this average value is held constant.
2.2.6 Filtered Moisture %
The Filtered Moisture % is scaled using the Filtered Unscaled value using the A, B, C and
SSD coefficients.
Filtered Moisture %= A x (F.U/S)² + B x (F.U/S) + C – SSD
These coefficients are derived solely from a material calibration and so the accuracy of the
moisture output is dependent upon the accuracy of the calibration.
The SSD coefficient is the Saturated Surface Dry offset (Water Adsorption Value) for the
material in use and allows the displayed percentage moisture reading to be expressed in
surface (free) moisture only.
2.2.7 Raw Moisture %
This is the Raw Moisture % variable before any filtering or averaging. As Filtering has not
been applied it is not recommended to use this variable for process control.

Configuration Chapter 2
Configuration and Calibration Guide HD0679 Rev 1.2.0 17
2.2.8 Average Moisture %
This is the ‘Raw Moisture %’ variable processed for batch averaging using the averaging
parameters. To obtain an average reading, the digital input must be configured to
‘Average/Hold’. When the digital input is switched high the Raw Moisture readings are
averaged. When the digital input is low the average value is held constant.
2.2.9 Brix
This is the value that may be calibrated to be proportional to the Brix content of a material.
In such cases the sensor will require calibrating to the given material. The calibration
requires the relationship between the Unscaled readings of the sensor and the associated
Brix value of the material to be defined.
Note: This output is not available in all sensors. Please see the technical
specification in the relevant installation guide for more details.
2.2.10 Temperature
Temperature scaling on the analogue output is fixed – zero scale (0 or 4mA) corresponds
to 0°C and full scale (20mA) to 100°C
2.3 Low % and High%
These two values set the moisture range when the output variable is set to ‘Filtered Moisture
%’ or ‘Average Moisture %’. The default values are 0% and 20% where:
0 - 20mA 0mA represents 0% and 20mA represents 20%
4 - 20mA 4mA represents 0% and 20mA represents 20%
These limits are set for the working range of the moisture and must be matched to the mA to
moisture conversion in the batch controller.
3 Digital Inputs/Output Setup
3.1 Inputs/Output Options
The sensor has two digital inputs. The second of these can also be configured as an output.
For connection details refer to the Electrical Installation Guide HD0678
The first digital input can be set to the following:
Unused: The status of the input is ignored
Average/Hold This is used to control the start and stop period for batch
averaging. When the input signal is activated, and after the delay
period set by the ‘Average/Hold delay’ parameter, the ‘RAW’ or
‘Unscaled’ values (see Averaging Mode section 4.3) start to
average. When the input is then deactivated, averaging is stopped
and the average value is held constant so that it can be read by the
batch controller PLC. When the input signal is activated once
again, the average value is reset and averaging recommences.

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18 Configuration and Calibration Guide HD0679 Rev 1.2.0
Moisture/Temperature: Allows the user to switch the analogue output between the
measurements of Unscaled or Moisture (whichever is set) and
temperature. This is used when the temperature output is required
whilst still using only one analogue output. With the input inactive,
the analogue output will indicate the appropriate moisture variable
(Unscaled or moisture). When the input is activated, the analogue
output will indicate the material temperature (in degrees
centigrade).
Temperature scaling on the analogue output is fixed – zero scale
(0 or 4mA) corresponds to 0°C and full scale (20mA) to 100°C.
Mixer Sync: A new synchronised measurement cycle is started when the input
goes active.
The second digital input/output can be set as an input for Moisture/Temperature but can also
be set to the following outputs:
Bin Empty: This output is activated if the Unscaled or Moisture values go
below the Low Limits defined in the Averaging section. This can be
used to signal to an operator when the sensor is in air (as the
sensor’s value goes to zero in air) and can indicate a vessel empty
state.
Data out of range: The output will be active if the moisture reading is above or below
the moisture include limits or the Unscaled is above or below the
Unscaled include limits
Sensor OK: This output will be active if:
•The frequency reading is between the defined air and water
calibration points +/-3%
•The amplitude reading is between the defined air and water
calibration points +/-3%
•The temperature of the internal electronics is below the safe
operating limit
•The temperature of the RF resonator is above it’s safe
operating limit
•The internal supply voltage is in range
Material Temp alarm: The alarm will be active if the material temperature is outside the
configured high/low limits
Calibration out of range:The output will be active if the Unscaled reading, for any of the
measurement modes, is more than 3 points above or below the
range of Unscaled values used in the calibration. This can be used to
indicate that another calibration point could/ should be made.
Auto-Track Stable: Auto-Track Stable indicates if the sensor reading is stable. The
stability is defined as the deviation of a set amount of data points.
Both the deviation value and the amount of data used, in seconds,
are configurable in the sensor. The output will be active if the Auto-
Track Deviation is below the Auto-Track Deviation threshold

Configuration Chapter 2
Configuration and Calibration Guide HD0679 Rev 1.2.0 19
3.2 Inputs/Output Configuration Settings
3.2.1 High Limit and Low Limit (Alarms)
The High Limit and Low Limit may be set for both the moisture % and the sensor Unscaled
value. The two parameters operate independently. The Bin Empty output will activate
when the reading is below the Low Limit. The Data Invalid output will activate when the
reading is above the High Limit or below the Low Limit.
3.2.2 Material Temperature High and Low limits (Alarm)
The Material High and Low Limits are used to configure the Material Temperature alarm. If
Digital Input/Output 2 is set to Material Temperature Alarm the output will become active if
the material temperature sensor is above the high limit or below the low limit.
3.2.3 Auto-Track Deviation Threshold
The Auto-Track Deviation Threshold is used to configure the Auto-Track Stable alarm. The
output if configured will become active if the deviation of the Filtered Unscaled reading is
below this limit.
3.2.4 Auto-Track Time
The Auto-Track Time sets the amount of data, in seconds, that is averaged to calculate the
Auto-Track deviation.
4 Averaging Parameters
During averaging the sensor uses the Raw or Filtered Unscaled value (user configured) in its
calculations. The following parameters determine how the data is processed for batch averaging
when using the digital input or remote averaging. They are not normally used for continuous
processes.
4.1 High Limit and Low Limit
The High Limit and Low Limit may be set for both the moisture % and the Unscaled value.
The two parameters operate independently. If the sensor reading falls outside of these limits
during sensor averaging the data will be excluded from the average calculation.
This is configured using the High / Low limits in the Input/Output configuration (section
3.2.1).
4.2 Average/Hold Delay
When using the sensor to measure the moisture content of a material as it is discharged from
a bin or silo, there is frequently a short delay between the control signal issued to begin the
batch and the material beginning to flow over the sensor. Moisture readings during this time
should be excluded from the batch average value as they are likely to be unrepresentative
static measurements. The ‘Average/Hold’ delay value sets the duration of this initial exclusion
period. For most applications 0.5 seconds will be adequate but it may be desirable to
increase this value. Options are: 0, 0.5, 1, 1.5, 2 and 5 seconds.
4.3 Averaging Mode
Sets the averaging mode used when calculating the average. The modes available are, ‘Raw’
(Unscaled/Moisture) and ‘Filtered’ (Unscaled/Moisture). For applications where mechanical
apparatus, such as mixer paddles or screws, pass over the sensor and affect the reading the
use of the ‘Filtered’ value will remove the peaks and troughs in the signal. If the material flow

Chapter 2 Configuration
20 Configuration and Calibration Guide HD0679 Rev 1.2.0
is stable, for example, when measuring at the output from a silo, the averaging should be set
to ‘Raw’.
5 Filtering
Default filtering settings can be found in the relevant sensor default settings
engineering note, see Appendix A Document Cross Reference for details.
The Raw Unscaled reading is measured 25 times per second and may contain a high level of
‘noise’ due to irregularities in the signal as the material flows. As a result, this signal requires a
certain amount of filtering to make it usable for moisture control.
The default filtering settings are suitable for most applications, however they can be customised
if required to suit the application.
It is not possible to have default filtering settings that are ideally suited to all applications because
each will have different characteristics. The ideal filter is one that provides a smooth output with a
rapid response.
The Raw Moisture % and Raw Unscaled settings should not be used for control purposes.
The Raw Unscaled reading is processed by the filters in the following order; first the Slew Rate
Filters limit any step changes in the signal, then the Digital Signal Processing Filters remove any
high frequency noise from the signal and finally the smoothing filter (set using the Filtering Time
function) smoothes the whole frequency range.
Each filter is described in detail below.
5.1 Slew Rate Filters
The Slew Rate Filters are useful for clipping large peaks or troughs in the sensor reading
caused by mechanical interference in a process.
The filters set rate limits for large positive and negative changes in the raw signal. It is
possible to set limits for positive and negative changes separately. Options are: None, Light,
Medium and Heavy. The heavier the settings the more the signal will be ‘clipped’ and the
slower the signal response.
5.2 Digital Signal Processing
The Digital Signal Processing Filters (DSP) remove excessive noise from the signal using an
advanced algorithm. The filter reduces high frequency noise. The advantage of this filter is
that the DSP filter will treat all signals within a meaningful frequency range as valid. The result
is a smooth signal that responds rapidly to changes in moisture.
DSP filters are particularly useful in high noise applications such as a mixing environment.
They are less appropriate for low noise environments.
Options are: None, Very Light, Light, Medium, Heavy and Very Heavy.
5.3 Filtering Time (Smoothing Time)
The Filtering Time smoothes the signal after it has first passed through the Slew Rate filters
and then the DSP filters. This filter smoothes the whole signal and will therefore slow the
signal response. The Filtering Time is defined in seconds
Options are: 0, 1, 2.5, 5, 7.5, 10 and a custom time of up to 100 seconds.