| Un Medidor de Microondas para la Determinación Rápida del Contenido de Humedad en Arena y Otros Agregados de Granos Finos y Gruesos.
Instructions
GENERAL OVERVIEW
The James Instruments Trident™ is a revolutionary digital moisture meter for granular
materials. It allows the user to measure the complex dielectric constant of the mixture of
water and material under investigation. As it has been shown in many studies that the
complex dielectric constant is directly related to the amount of water present, the built in
microprocessor can convert this value directly into the percentage of moisture. The
Trident™ consist of a 100 MHZ probe and logging unit that can processes the data from the
unit and can store it for later retrieval.
The Trident™ probe has 5 stainless steel prongs to insert in the material to get a moisture
content reading. Each prong is 3.5 inches in length with a diameter of 0.125 inches.
They should be inserted so that the entire prong is covered by the material under
investigation. The volume tested is that enclosed by the four outer prongs of the sensor
unit. The robust prongs have been designed to be inserted into various materials. Most
commonly used materials are sand, aggregate, and gravel.
Proper cleaning and maintenance of probes is required for accurate readings. Any
contaminating material attached to the probes can influence subsequent readings.
Stainless steel probes should be cleaned before and after testing has been completed. The
Trident™ prongs cover a surface depth of about 5 inches. For accurate readings, it is
recommended to remove the top layer of the material to be tested as this is generally the
driest region. Keep in mind that moisture always flows to the bottom of these materials.
The more moisture suspected in the material, the deeper the depth you want your testing
to be. A note of caution is in order; it has been found that the moisture content of sand
and aggregates, etc. can vary by as much as 5 percent through a rather small volume.
The unit comes from the factory with a variety of modes to assist the user in determining
moisture content. The unit comes pre-programmed to analyze sand, gravel, and crushed
stone. There is also a mode to read the output of the sensor directly. The Trident™ can
also be programmed with up to ten different user programs. These are correlation factors
that pertain to the direct material the user is dealing with and should be used for the most
accurate readings. There are also the capabilities to upload the data stored in the unit to a
P.C. for later analysis, as well as a clock to help synchronize and differentiate the data.
Finally, the unit comes with our P.C. software which simplifies uploading of data to a
windows compatible P.C. and analyzing the data for later programming of the unit.
When required, the software will automatically monitor the serial communication port
specified by the user. Once transmission of data from the Trident™ unit has occurred, this
information will appear in the edit window in the software. This data can then be
analyzed by the built in software of the program or with a common spread sheet. The
built in software will take the user step by step through each record and allow the user to
enter the moisture percentage associated with each reading. Once all the readings have
an associated moisture percentage, the data can be graphically displayed and the optimal
correlation relationship determined. Coefficients representing this relationship are
displayed for subsequent loading into the Trident™ unit.
The Trident™ is an easy and accurate way of testing moisture in a controlled or
uncontrolled environment. Every effort has been made in providing a user friendly
robust and accurate system for the measurement of moisture in granular materials. A
robust sensor which responds to water content has been created. This feeds into the main
microprocessor unit of the Trident™ allowing the user an instantaneous direct reading of
the moisture under test.
GENERAL NOTES ON THE USER PROGRAM
For best results with the James Instruments’ Trident™, user programs should be created for
the different materials that the equipment will be used with. These are precise
correlations that account for material differences inherent in local conditions. A simple
least squares linear correlation between the output of the probe and the moisture content
of the material is all that is required.
This can be obtained via a simple test method. Please follow the points below describing
the test procedure.
- First a two to three kilogram sample should be collected.
- The material under investigation should be baked at a relatively low temperature
(50° C to 60° C) until the sample no longer loses any weight. The loss in weight
should be below 1% of the total mass of the sample.
- Approximately five to ten readings from the sample should then be taken with the
Trident™ in Direct Mode and the moisture as well as the corresponding reading
should be recorded. The reading can be recorded either digitally or manually.
The moisture content should be recorded manually.
- Water should be added and the sample mixed thoroughly. Enough water should
be added to increase the water content by 1 – 3% increments. The increment
depends upon the number of sets of data the end user wishes to use. From five to
ten sets of data are normally adequate to produce accurate and reliable results.
- Continue adding water and taking data readings. This procedure should be
repeated until the sample reaches saturation, at this point the reading from the
meter will become constant. For sand this point will be between 20 – 30%. For
aggregate, this point will be between 7 – 15%. Constant data points from the
instrument should not be used for correlation.
After the data has been collected, a correlation relationship needs to be established. This
is a linear relationship of the form
% Moisture = Gain * Direct Reading + Offset
Where:
% Moisture – Final Value
Gain – Multiplier obtained from the Data
Direct Reading – Value obtained from the meter
Offset – additive factor from gathered data
From the data generated above a best fit line through data can be generated. This can be
accomplished either with a spreadsheet or with the accompanying software. In inserting
the percentage moisture with the software, the time, and date stamp field can be used to
identify which tests were associated with which moisture percentages. The Gain and
Offset parameters are the two values that need to be programmed into the Trident™ in order
to define the User program (see Ch. User prog).
Trident™ LOGGING UNIT
Menu Items
- UNIT OPERATION
The Trident™ was designed for simple operation. Upon start up, the unit should show a
brief (five second) display of our company name and software version. The unit will then
proceed directly to the menu item it was last on before it was turned off. The menu
structure is as follows:
Sand
Gravel
Crushed Stone
Direct
User 1-10
Ch. User Mat.
Upload Data
Change Date
You can scroll through the menu by pressing an arrow key. Either arrow key will allow
you to scroll through the memory. The Sand, Gravel, Crushed Stone, Direct, and User
menu items will each simply show the instantaneous reading of the sensor, menu item
selected, and the date/time. Pressing the Enter key while in any of these modes will
record the reading, menu item selected, and date/time that the reading was taken in the
main memory for later upload to a personal computer. The memory is non–volatile and
will not be erased by turning off the power.
- SAND
The Trident™’s reading of moisture in sand is superior to other techniques. Moisture
contents of beyond 20 percent by weight can be rapidly and accurately determined by the
Trident™. The reading obtained in this mode is generally within 2 – 3% of the actual
moisture level. More accurate readings can be obtained by pre-calibrating the unit to the
specific sand being tested.
- GRAVEL
This is the general category for the smaller aggregates with rounded edges that is
commonly used in construction. The Trident™ will generally read moisture levels to the
12 percent range by wet weight.
- CRUSHED STONE
Crushed stone refers to rock building material that has sharper corners and packs less
densely than the gravel. Maximum size of the pieces is determined by the prongs on the
probe and is approximately 3/8 to ½ inch square. The maximum percentage of moisture
detected depends heavily on the size of the stones. Small finely crushed stones have a
moisture percentage detection of up to 10 percent. Bigger crushed stones have a
maximum percentage range of up to 8 percent.
- DIRECT
This mode is used when calibrating the unit directly to a user material. This shows the
raw reading coming to the A-D converter of the unit from the sensor. By recording the
value for a range of moisture and correlating this value, the unit will then be calibrated
for the specific material being monitored by the Trident™.
- USER PROGRAM
The Trident™ can be programmed with up to ten different user materials for subsequent
testing. These are labeled on the unit 0 – 9 and are displayed in sequential order. Their
programming is performed in the Ch. User Mat. section. The final value from the user
generated calibration function will be displayed instantaneously with different outputs
from the probe.
- CHANGE USER PROGRAM
To change the user program please follow these steps:
- Use the plus and minus keys to select the menu item Ch. User Mat.?
(Enter for Yes)
- Pressing enter will bring up the following message:
User Pog.? X
(0-9)
where X is the user program that you wish to change ranging from 0 to 9.
- Use the plus and minus keys to change the value of X until you have reached the
user program you are interested in.
- Pressing enter brings the message
OFFSET
sXX.XX
Where:
s is the sign either + or –
X is the value
- Pressing the plus or minus keys will increment this value. Pressing and holding
the plus or minus key will rapidly increment this value.
- Once the proper value has been reached, press the enter key. The unit will display
the following:
GAIN
x.xxx where:
x is the value to be entered.
- Again pressing the plus or minus keys will increment this value. Pressing and
holding the plus or minus key will rapidly increment this value.
- Finally pressing the enter key enters these values into memory and sets up the
user program for subsequent use.
For further information regarding the meaning of the OFFSET and GAIN parameters,
please refer to the General Notes on the User Program.
- UPLOAD DATA
Please follow the bottom steps in order to upload the data stored in the unit to a P.C.
- Connect the unit to the correct serial port of the P.C. using the supplied serial
cable.
- Use the plus or minus keys until the following message is displayed:
Upload Data
(Enter for Yes)
- Pressing enter will display the following message:
Erase Data?
+ for Y – for N
- Pressing either button will commence the upload process and display the
message:
Data Upload in Process
Once the process is complete the following message will be displayed:
Upload Complete! for a few seconds and then the Upload Data message from
above will appear.
For more information regarding uploading the data to a personal computer please refer to
Tools.
- CHANGE DATE
To change date and time please follow these steps:
- Press the + or – arrow key until you get to
Change Date?
(Enter for Yes)
- Pressing enter will display the date and time in the following format:
hh:mm
MM/DD/YY
Where:
hh – hour range 0 – 24
mm – minute range 1 – 60
MM – month range 1 – 12
DD – day range 1 – 31
YY – Year range 00 – 99
The cursor should be blinking over the two hour digits
- Pressing the plus or minus keys will increment the digits at the cursor. Holding
the plus or minus key will increment the value rapidly.
- Pressing the enter Key will store the value selected and move the cursor to the
next proper position.
- Pressing the enter key at the year position will bring the user to the “Change
Date” menu screen describe above.

- Power Key – Momentarily push this key to turn on the unit. Pressing it again
turns off the unit. The unit will power up displaying the same menu selection as
when it was powered down.
- Average Key – Depressing this key holds the current value and an “A” appears
next to this value on the display. This then displays a running average of readings
entered by pressing this key.
- Enter Key – This key can be used to store data points in the units. Depressing
this will display an “S” next to the value being read for a few seconds. The
reading will then be stored in the unit along with the type of material being used
and the date and time. This can subsequently uploaded to the P.C. for later
retrieval. It is also used in various ancillary functions such as changing the date
and the time, uploading the data to a P.C. and programming the unit for user
materials.
- Plus Key – This key is used to scroll through various settings.
- Minus Key – This key is used to scroll through various settings.

- X – Menu item currently being used
- n – Current moisture reading
- A – auxiliary character used to show data being stored and held
- hh – Current hour
- mm – Current time
- MM – Current month
- DD – Current day
P.C. SOFTWARE
FILE
- Open (Ctrl + O)
Opens previously saved files containing data.
- Close
Closes currently open files
- Save
- Saves As
Saves uploaded data. Files are saved as *.TXT for later analysis via spreadsheet or
insertion in your favorite word processor.
- Exit
Terminates the program and returns to your operating system.
TOOLS
Upload (Ctrl + U)
This command is used to upload data from module to the CPU.
For proper upload of data to a P.C. please follow these steps:
- Open Trident™ software (title of screen should read Trident™ Regression Analysis)
on the P.C.
- Connect P.C. and Trident™ by the RS-232 serial port
- On the Trident™ use the + or – arrow keys until the “Upload Data screen appears on
the display.
- Press Enter.
Go to the Trident™ software (needs to be installed on P.C.) click on the upload icon
or press CTRL + U
- Trident™ software will ask you to “Please start upload.”
- At this moment press the + arrow to erase data or the – arrow to save data after
upload (Trident™ software waits 10 seconds for the upload information). If no data
is received after 10 seconds, a “No data received” sub screen will appear.
- Data will appear on the screen after the + or – arrow key selection was made.
- Save data in desired folder.
Analyze (Ctrl + A)
Allows the user to view individual record, graph data, and determine the correct
coefficients for the user program. This key should only be used when data is uploaded
from the unit that was saved in direct mode. It is then used to analyze the data and
generate a user program. This feature is not enabled until a data file has been brought up
on the screen.

This shows the record number, date the record was taken, time the record was taken,
value of the direct readout, and a corresponding percentage moisture that needs to be
completed by the user in order to generate a correlation curve.
Pressing the OK button updates the data in the file and brings up the next record in the
file. Pressing the cancel button cancels the entire operation.
Once the last data point has been entered the Finish button can be pressed in order to
generate a correlation curve.

This will produce a display of the correlated data and the appropriate OFFSET and GAIN
parameters to be entered in the Trident™.
- Ports
This command allows setting the correct (RS – 232) Com port. It can be Com 1
through Com 4. The default setting is Com 1.
LEAST SQUARES ANALYSIS
OF A STRAIGHT LINE FIT
For this method, we assume that there exists a linear relationship between the output of
the probe and the amount of moisture in the material to be tested.
This relationship takes the form:
% Moisture = Gain * Direct Reading + Offset or
y = a*x + b
What need to be determined are the parameters Gain or Mand Offset or b from a given set
of points determined by testing.
We can then define:

Where x¡ and y¡ are individual pairs of values for x and y defining each of the pairs of
points to be plotted. The quantity n is the number of points.
The Gain of the line, a is now simply: a = Sxy/Sxx
The Offset, b can be calculated as: b = y¡/n – ax¡/n
This is performed automatically by the accompanying software and is also available in
most spread sheet programs.
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