EECI ADC-4DU8 Use and care manual

TABLE OF CONTENTS
Specifications.......................................... page 1
Connection Diagram and Warranty......... page 2
Technical Support................................... page 2
Terminal Block Connections.................... page 2
Set-Up and Testing................................. page 3 & 4
Device Manager...................................... page 4
Trouble-Shooting..................................... page 5
Input & Relay Expansion Ports............... page 5
The ADC-4DU8 User Interface......... page 6
Auto Start-Up.......................................... page 6
The ADC-4DU8 Data Logger.................. page 7
Programming Examples......................... page 7
Voltage Reference for the analog inputs. page 8
Single Ended Analog Inputs.................... page 8
Differential Analog Inputs........................ page 9
Input Amplification and Conditioning..... page 9
Voltage Inputs and Sensor Interfacing.....page 10 & 11
Mounting..................................................page 11
SPECIFICATIONS
Power Supply....................... Powered from USB port (5 volts DC)
Operating Temp. Range...... -40° C to +85° C
Serial Data Protocol............. 75 to 6,000,000 baud - auto detect (defaults to 115,200 baud)
Full duplex operation (data bits, parity, stop bits will auto detect)
Maximum Sampling Rate...... 100 samples per second or better
Analog Inputs....................... 4 single-ended inputs (8 bit resolution)
or 2 fully differential inputs (8 bit resolution)
or 2 single ended and 1 fully differential input (8 bit resolution)
or 3 common negative differential inputs (8 bit resolution)
(8 bit resolution will divide your measurement range into 256 different increments)
Analog Voltage Input Range. 0 to 5 volt (default range)
0 to 3.3 volt (selectable with on board shunt)
user supplied in the range of 1.6 volts to 5 volts (to on board header)
Analog Outputs.................... 1 analog output (8 bit - 256 analog increments) 0 to 5 volt default
Expansion Capability............ up to 16 relays (with up to (2) EX-8M expansion cards) or relay/input combinations
up to 16 status inputs (with up to (2) EX-8M expansion cards)
up to 144 relays/inputs using EXM-16 or EXM-32 expansion modules
Software Compatibility......... Windows XP, Vista, Windows Server, Windows 7, Windows 8.1 and Windows 10
Weight................................. .5 ounce
Size...................................... 1.875 inches by 2.5 inches
Page 1
TECHNICAL REFERENCE
ADC-4DU8
ANALOG TO DIGITAL
CONVERTER
Click for more info: www.eeci.com/adc-4du8p.htm
[phone]
[phone]
[phone]
[email protected]
PHONE...................
ORDERS................
TECH SUPPORT...
E-mail.....................
www.eeci.com

CONNECTION DIAGRAM
A D C - 4 D U 8
A N A L O G TO D I G I T A L C O N V E R T E R
DESCRIPTION
The ADC-4DU8 series Analog to Digital converters connect to any available USB port on your desktop or laptop PC
(including some tablets and phones). Four analog inputs channels are provided for conversion to 8 bit digital format.
The converters may be set to two channel fully differential mode if required. A fifth channel is provided for an 8 bit
analog output. Three optional expansion ports are available for connection of up to 144 relays, 144 status inputs or
combinations of relays and inputs.
24 HOUR TECHNICAL SUPPORT
Technical support for our products is available by calling [phone]. If a technical adviser is not available, please
leave your name, phone number and a time that you can be reached. Your call will be returned as soon as possible
and within 8 hours. Calls received during normal business hours are usually returned within minutes.
WARRANTY AND CARE OF THE ADC-4DU8
The ADC-4DU8 series Analog to Digital Converters are warranted against factory defects for a period of 90 days from
the date of purchase. The ADC-4DU8 has proven to be extremely reliable in actual operation during field tests. We
recommend that the ADC-4DU8 and associated hardware be installed in a suitable enclosure (4 mounting holes are
provided on the circuit board) and that reasonable precautions be taken to protect the circuit from static discharge.
Page 2
USB
Expansion Port B
Expansion Port A
AUX Header
analog input #1
analog input #2
analog ground
analog input #3
analog input #4
digital to analog output
Single-ended Analog
Connections
(see page 9 for
differential connections)
REF+
GND
3.3V 5V
Reference
Select
SET-UP AND TESTING
Upon receiving your ADC-4DU8, you should connect and test the operation of the hardware to verify proper operation.
Please set-up and test the ADC-4DU8 as follows (Windows XP*, Vista, Windows Server 2008, 2012, Windows 7, 8.1
or Windows 10 & later) *service pack 3
(Step 1) Connect to the Internet. This permits any security or software updates to occur during installation. If you do
not have an Internet connection, you may skip this step.
(Step 2) Connect your ADC-4DU8 Analog to Digital Converter to any available USB port on your computer using a
CC-USBB cable (1 to 15 foot). A high percentage of systems will be up to date and you will not see any activity or a
pop-up message (allow up to 30 seconds for any system message). If your USB Com driver is out of date, you may
receive a message that your system is being updated or a new driver is being installed. Allow the update to occur
before you move to the next step. If you do not see activity or receive a system message, proceed to step 3.
(Step 3) Insert the installation CD or USB flash drive and wait for the security message (with a USB flash drive, you
may need to browse to the drive icon from your My Computer link). OK or click the startup.exe file to start the installer
dialog.
(Step 4) Check your USB Com driver by clicking on the "Open Device Manager" button in the installer dialog window
and expanding the "Ports (COM & LPT)" category (expand the category by clicking on the + or arrow, see Device
Manager on page 5 or go directly to Device Manager from Control Panel). If you see a "Prolific USB-to-Serial Comm
Port" entry, this is your USB Com
driver* and the com port assigned
is to the right of the entry. Right
click on the entry and select
"Properties"and click the "Driver"
tab. Your USB Com driver must be
Prolific version 3.4.62.293 or
higher (dated 10/17/2013 or later).
If your USB Com driver is not up
to date, right click on the entry and
select "Update Driver Software". If
your USB Com driver is up to date
then please note the Com port
number assigned and jump to step
5.
*verify that this is the com port
assigned to the ADC-4DU8 by
unplugging the ADC-4DU8 from
your USB port and watching the
entry in device manager. The entry
should disappear and then
reappear when you plug the ADC-
4DU8 back in.
If you do not have an Internet
connection or are having problems with the USB Com driver installation, disconnect the ADC-4DU8 USB cable from
your computer and install the USB Com driver from your CD by clicking on the "Install USB Com Driver" button. Please
note that you may have to remove any out of date Prolific Com drivers on your system before the current driver will
install correctly. It is important that you use the remove feature on your CD (not the remove feature in Device
Manager). The remove feature is shown after clicking the "Install USB Com Driver" button from the installer dialog
window (allow up to 30 seconds for the installer to load and appear).
Page 3

You may install the ADC-4DU8 device driver permanently by checking the "Driver Only" check box under Setup in the
ADC-4DU8 User Interface. You will then always see the ADC-4DU8 system icon in your system tray along with the
other system devices (such as your speaker, printer or display adapter).
If operation of the analog inputs are normal, then testing is now complete and your ADC-4DU8 may be placed in
service. If problems are encountered during testing, proceed to the trouble-shooting procedures shown below.
HOW TO OPEN DEVICE MANAGER
Windows XP, VISTA or Windows 7: Click the Start Button (lower left of screen), then Control Panel (right side). With
the view set to classic view, small or large icons, click (or double click) the Device Manager icon. With Windows XP
you will need to click the System icon (in Control Panel) then the Hardware Tab then the Device Manager button. You
may also use the supplied CD to open Device Manager by clicking the "Open Device Manager" button when the CD
auto starts.
Windows 8.1, 10 and Windows Server: Move your mouse cursor to the lower right side of your screen and
click on Settings. Click on Control Panel near the top and click on the Device Manager icon.
TROUBLE-SHOOTING THE ADC-4DU8
(1) Verify that your USB com driver is installed by going to Device Manager and checking for the Prolific USB to
Serial Comm Port entry. Right click on the entry, then Properties, select the Driver tab and verify that the driver is
dated 8/15/2014 or later. If the driver is out of date, connect to the Internet and click the Update Driver button. Please
note that an out of date driver may allow the ADC-4DU8 to partially function and/or with erratic operation.
(2) Verify that the Prolific USB to Serial Comm Port entry is the com port used by your ADC-4DU8. You may do this
by watching the entry in Device Manager and unplugging your ADC-4DU8 from your computer USB port. The entry
should disappear and then re-appear when you plug the ADC-4DU8 back in to your computer USB port.
(3) Verify that the ADC-4DU8 Device Driver is correctly installed and running. Click the blue 4 icon in your system tray
(bottom right) and check for the correct com port setting (should show the correct com port open). If the window
below the COM indicator shows "COM Not Found!" then a com port issue is the problem (check for another program
that may be using the com port). You may right click the taskbar at the bottom of your screen, then Task Manager to
view running applications.
.
(4) Remove the ADC-4DU8 USB cable from your computer, wait 10 seconds and plug back in. Open the ADC-4DU8
User Interface by clicking on the blue icon in your system tray and double click on the blue EECI logo to reset
the com port. You should see a reset message followed by a COM open indication. Click Setup and uncheck "Allow
External Commands". If this corrects the issue that you are experiencing then an external application is the problem.
(5) If erratic operation is experienced, check for loose connections at the terminal block (tug on each wire going into
the terminal block), check for short circuits caused by metal contact to the ADC circuit areas or other connected
hardware. Try replacing the USB cable and/or using a different USB port.
(6) The input voltage to any of the analog inputs must not exceed the reference voltage (nor should the input go
negative with respect to the reference when not in differential mode) or erratic data may be generated on one or more
of the analog channels. When an external reference is used, the reference voltage must not exceed 5 volts.
Please contact EECI Support at [phone] if you require additional assistance or have questions.
EXPANSION PORTS
The ADC-4DU8 provides three expansion ports for additional I/O operations using the same COM port. The
expansion ports may used to connect up to 144 relays or to connect up to 144 inputs (or combinations of relays and
inputs) using EX-8M, EXM-16 or EXM-32 expansion modules. A variety of relay cards with various contact
configurations are available for connection to the expansion modules. A partial list of relay cards includes the RD-8,
RG-8, RH-8, RI-8, RJ-8, RL-8, RN-8, RP-8 and RJ-8. The RYD-8 relay driver card may be used to control larger
power relays, contactors, solenoids, valves or other devices.
Page 5
(Step 5) After you have verified or installed the up to date USB Com driver, reconnect (if not already connected*) your
ADC-4DU8 Analog to Digital Converter to the same USB port and install the ADC-4DU8 device driver** by clicking the
"Install EECI Device Driver" button from the installer dialog window (if you have auto start disabled, you may browse to
the Windows Driver folder and double click on setup.exe). A desktop icon for the ADC-4DU8 will be created. When
installing the ADC-4DU8 device driver on a Windows XP or Vista computer, double click on setup.exe in the XP-Vista
folder. *if you reconnect your ADC-4DU8 to a different USB port, a different com port may be assigned.
**Please note that the Microsoft .Net Framework must be installed on your system. The .Net Framework is already
installed if you have Windows 7 or higher. If the .Net Framework is not installed on your computer, the installation
program will attempt to download and install the .Net Framework from the Microsoft Update website through your
internet connection. This may take 5 minutes or longer. In order for the .Net Framework to install correctly, your
computer must be up to date with Windows Update. This is especially important with Windows XP* and Vista. You may
update your computer by clicking on the start button, All Programs, Windows Update and clicking on "Check for
updates". *for XP, Service Pack 3 must be installed.
(Step 6) After the ADC-4DU8 device driver is installed, the ADC-4DU8 com port should be detected and a pop-up
will prompt you for the com port to be used with your ADC-4DU8 A to D Converter (correct com port should be
shown).You may edit the com port if incorrect. The ADC-4DU8 User Interface will now open and the label just under the
COM port indicator should show that Com port open. Please Note: When the ADC-4DU8 inputs are floating (no
connection) the inputs may show random or changing values from noise picked up by the high impedance inputs. Click
the "Install Help Files" button to install important trouble-shooting and reference information before you close the
installer.
(Step 7) Test your analog inputs by applying a test voltage to each input (between the GND (-) terminal and the
analog input terminal (+). The test voltage must be within the selected reference voltage and of the correct polarity (the
default reference voltage is 5 volts, providing a voltage input range of 0 to 5 volts DC). You may use the analog test
circuit shown below to provide the test voltage. When using a 9 volt smoke detector battery, use a multimeter to check
for the correct voltage since the voltage can go well over the reference voltage if the potentiometer is turned beyond
10K. The input in the ADC-4DU8 User Interface should increment by one (in 256 increments for 8 bit inputs) as the
potentiometer is slowly adjusted from 0 to 5 volts. Test the analog out channel with a number 0 to 255 (click D-A).
Differential inputs may be tested using the same analog test circuit (below) except you will connect the test voltage to
inputs 1 and 2 (differential channel 1) or inputs 3 and 4 (differential channel 2). When the ADC-4DU8 is set to differential
mode, the ADC-4DU8 will display a range of (-128 to +127) as the input voltage swings from 5 volts to +5 volts. The
negative side of the signal is generated by reversing the polarity of the test signal (or reversing the battery polarity). The
inputs are changed to differential mode by going to the setup window in the ADC-4DU8 User Interface.
After testing is complete, you may label your analog inputs, set scale and offsets, set precision and add a suffix (such as
°, PSI, mA, etc) by going to the setup window in the ADC-4DU8 User Interface and clicking the Analog Setup button.
The ADC-4DU8 Data Logger may be started by checking the Enable box. The data log entry interval may be set to
minutes or seconds (click the M or S button) and entering the desired time interval. The settings will not go into effect
until the Apply button is clicked.
Click the "Tray" button to place the User Interface in "driver only" mode. You will see a blue 4 icon in your system tray by
the clock (bottom right of screen as shown below).
Click the blue 4 icon to re-open the ADC-4DU8 User
Interface. Click the "Unload Device Driver" to remove the
ADC-4DU8 device driver.
Please note that by default, the ADC-4DU8 device driver
is only loaded on demand to conserve system resources.
To re-start the ADC-4DU8 device driver, double click the
red and blue ADC-4DU8 desktop icon or under Applications.
Page 4
(Reference +)
(Reference -)
To Analog Input
10K Ohm
typical
(20 turn)
Analog Input
Test Circuit
using
potentiometer
To Analog Ground
9 Volt
Battery
(+) (-)

THE ADC-4DU8 DATA LOGGER
The ADC-4DU8 User Interface provides a data logger function that will save analog input readings to a file at preset
time intervals. Scale and offset values may be factored into the recorded data event along with an input label by
entering the desired values at the setup screen by clicking the Analog Setup button. The ADC-4DU8 data logger may
be used stand alone if an external application is not used. The file output format may be set to plain text, CSV or text
delimited formats and may be imported into database or spreadsheet applications if required. The data log interval
may be set to seconds or minutes by clicking the button to the right of the setting. A suffix may be added to the
logged value (such as PSI, Volts, °, etc.). Extended ASCII characters may be added by holding down the alt key and
entering the ASCII code on your keyboard keypad. Example: to display a degree symbol, hold down the alt key and
enter 248 on your keypad. The precision setting allows you to log your data in integer only, tenth, hundredth,
thousandth or auto select.
PROGRAMMING EXAMPLES
VISUAL BASIC EXAMPLE (Microsoft Visual Studio)
'To use these example, copy the code module (supplied on your CD) to a sub called readInputs(). From the toolbox,
drag (4) labels and a timer control to your form. Insert the following code into the timer sub. The (4) ADC-4DU8
analog inputs are displayed in labels 1 through 4.
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
readInputs() 'collect analog inputs
For W = 1 To 4
MyLabelArray(W).Text = inputByte(W)
Next W
End Sub
VISUAL C# EXAMPLE (Microsoft Visual Studio)
private void timer1_Tick(object sender, EventArgs e)
{
ReadInputs();
for (int i = 1; i < 5; i ++)
{
MyLabelArray[i].Text = inputByte[i].ToString();
}
}
Source code is also provided on your installation CD that will allow you to set the analog out channel from your
program. The entire source code program examples and the complete project code are provided on your installation
CD along with additional source code examples in other programming languages. The programs are intended to
demonstrate the fundamentals needed for development of your own software. The program examples may be copied
to your program and used as a subroutine if desired.
These examples will run in all versions of Visual Studio including Visual Studio Express. The installation CD will have
examples in all the programming languages used with Microsoft Visual Studio including Visual Basic, Visual C# and
ASP .Net. Additional source code examples are available in several other variations which may be more suitable for
alternate programming languages. Please contact EECI technical support for more information.
Page 7
THE ADC-4DU8 USER INTERFACE
The ADC-4DU8 User Interface allows you to set all
of the basic operating characteristics of the
hardware and permits the ADC-4DU8 to send and
receive data from other Windows applications or
programs that you create.
When the device driver is started for the first time,
you are prompted for the com port that is to be
used with the ADC-4DU8. This com port number is
saved in the settings file "adc4du8-set.ini" which is
created in the folder c:\eeci\adc-4du8. The user
interface will then open using the com port
assigned. The com port indicator should have a
"COM Open" message as shown to the left with
the correct com port shown. The com port may be
changed by clicking the Setup button and
changing the com number in the Com Port window
and clicking Apply. Entering a value (0 to 255) into
the textbox below and clicking the D-A button
allows you to manually set the analog output level.
Clicking the Setup button allows you to label the
analog inputs for each of the 4 channels. The com
port, baud rate and sampling rate settings are
changed below. Checking the box for differential
input will allow differential inputs to be connected
to the terminal block on the ADC-4DU8 (display
will change to two channel mode). Un-checking
the Allow External Commands box will prevent
other Windows applications from sending or receiving data from the ADC-4DU8. The data logger may be enabled by
checking the box in the data logger section and entering the desired time interval and file type information.
The ADC-4DU8 may be started in Driver Only mode by checking the Start Minimized box. Any changes made to
Setup will not take effect until you click the Apply button. Clicking the Apply button saves the new settings to the
adc4du8-set.ini file so that if the device driver is unloaded, it will restart with all the new settings. Click the Tray button
to close the User Interface after the ADC-4DU8 is set-up for your application. A blue 4 icon will appear in your system
tray (click to re-open the user interface). The ADC-4DU8 User Interface may be left open when used as a stand alone
data logger or if an external application is not used. The ADC-4DU8 device driver may be unloaded by clicking
"Unload Device Driver". Once shut down, you will need to double click the ADC-4DU8 desktop icon to re-start the
ADC-4DU8 Device Driver (or clicking the ADC-4DU8 icon under All Programs in the EECI folder).The Help button will
provide additional assistance if you installed the Help files from the ADC-4DU8 installation CD.
AUTO START-UP FOR THE ADC-4DU8 DEVICE DRIVER
By default, the ADC-4DU8 device driver is only loaded on demand to conserve system resources. If your ADC-4DU8
is always connected, you may install the ADC-4DU8 device driver permanently by checking the "Driver Only" check
box under Setup in the ADC-4DU8 User Interface. You will then always see the ADC-4DU8 system icon in your
system tray* along with the other system devices (such as your speaker, printer or display adapter). Click the blue 4
icon in your system tray to open the ADC-4DU8 User Interface. If the ADC-4DU8 device driver is not installed
permanently, you will need to double click the ADC-4DU8 desktop icon to load the ADC-4DU8 device driver each
time your system starts.
*you may need to expand the arrow in your system tray to see all the icons (the tray is the row of icons on the lower
right of your screen, next to your clock).
Page 6

VOLTAGE REFERENCE INPUT
The ADC-4DU8 allows for several different reference voltage configurations. The reference voltage determines the
voltage input range for all (4) analog input channels (or (2) channels in differential mode). This reference voltage also
determines the voltage output range of the analog output channel #5. The following configurations are selectable for
the ADC-4DU8. Option 1 is the default setting.
Option 1: 5 volt - allows a (0 to 5) volt input range or (-2.5 to +2.5) in differential mode
(4) channel single ended or (2) channel fully differential
Option 2: 3.3 volt - allows a (0 to 3.3) volt input range or (-1.65 to +1.65) volts in differential mode
reference voltage is selected using the on board shunt
Option 5: User supplied - must be in the range of 1.6 volts to 5 volts
reference voltage from user is applied to the reference in header
Example: 2 volts applied to the reference input provides a (0 to 2) volt input range single
ended or (-1 to +1) volts for differential inputs.
Shown to the right are the reference select and the reference input
headers that are located by the terminal block on the ADC-4DU8. The
reference select shows the shunt in the default 0 to 5 volt position.
The reference select below shows the 3.3V position.
THE ADC-4DU8 ANALOG OUTPUT
The ADC-4DU8's fifth channel provides an 8 bit analog output that will output a voltage from 0 volts to the applied
reference voltage (default is 0 to 5 volts) in 256 increments. This voltage can be applied manually at the ADC-4DU8
User Interface main screen or the ADC-4DU8 analog output may be controlled from other applications (or from
software that you develop). Source code software examples are provided on the CD supplied with the ADC-4DU8.
SINGLE ENDED ANALOG VOLTAGE INPUTS
Voltages up to hundreds of volts may be divided down to the 5 volt range by using a simple resistance divider as
shown on the following page (the signal source must be capable of driving a 1 ma load). To determine the value
transmitted by the ADC for a specific voltage applied to the divider circuit use the following formula: (VI divided by
DF) times 51 = TV (where TV = transmitted value sent by the ADC, VI = voltage input to divider, DF = divider factor)
DF = full scale voltage divided by 5 volts. EXAMPLE: 100 volts full scale divided by 5 = 20 = DF. A 60 volt input to the
divider divided by 20 multiplied by 51 = 153 = TV, the value transmitted by the ADC (8 bit).
The voltage input source may be located up to several hundred feet from the ADC. The wire which connects the ADC
to the signal source should be a twisted pair to reduce possible input noise (22 or 24 gauge communication cable or
CAT5 typical). Shielded cable may be used to further protect against EMI or lightning noise (the shield should be left
disconnected at the source and connected to an earth ground/equipment ground at the ADC).
Lower millivolt signal levels (such as the output signals from a watt transducer, pressure transducer, load cell, etc.)
with typical full scale voltages of only 20 to 100 millivolts will require the addition of the VA-1, VA-2, VA-4 or VA-8
instrumentation amplifier. The VA-1 connects to any of the analog inputs and will convert a millivolt signal input to a 0
to 5 volt output for input into the ADC. Signal levels this low will may require shielded cable to reduce noise. An
adjustment on the VA-1 will set the input scale. The shield should be left disconnected at the source and grounded to
an earth ground at the VA-1. Applications requiring isolated analog inputs require the VI-8I linear opto isolated
amplifier.
USE OF THE ADC-4DU8 WITH LABVIEW OR DLL's
The ADC-4DU8 may be used with LABview or other software with the use of a DLL. Please contact EECI technical
support for a download of the appropriate software interface.
Page 8
NOTE: When the analog inputs are left floating, (no connection) the ADC will transmit fluctuating numbers as a
result of noise present at the inputs. We recommend that any unused inputs be connected to GND (reference (-)) to
prevent possible errors on other channels.
FILTERING INPUT NOISE: A .1 uf filter capacitor is installed on the ADC card (one for each channel) which
significantly reduces errors and fluctuation as a result of input noise. A 2.7 mf or 10 mf tantalum capacitor may added
for additional filtering (input response time will be slower).
Shown on the following pages in figures A, B & C are methods for reading contact closure, potentiometer movement &
light levels.
VOLTAGE INPUT AMPLIFICATION AND SIGNAL CONDITIONING
The ADC-4DU8 defaults to a 0 to 5 volt input range (installation of a voltage reference will allow input ranges as low
as 0 to 1.6 volts). When the input voltage range is required to be lower, (such as with a watt transducer or load cell)
an external instrumentation amplifier must be used to amplify the input signal to the 0 to 4 volt input range of the ADC.
Several general purpose instrumentation amplifiers are available to amplify lower signal levels to the 0 to 4 volt range
required by the ADC (for use with 8, 10 and 12 bit inputs). The VA-1 is a single channel amplifier for connection to
the ADC-4DU8, ADC-8U or ADC-12U. The VA-2, VA-4 and VA-8 amplifiers are two, four and eight channel versions of
the VA-1. The VA-1, VA-2, VA-4 and VA-8 all provide 15 turn potentiometer(s) for gain adjustment (amplification level).
The amplification level is adjusted for a 0 to 100 millivolt input at the factory. The amplification level may adjusted for
signal inputs as low as 0 to 5 millivolts or as high as 0 to 5 volts. Lower signal levels (such as the output signal from a
watt transducer, pressure transducer, load cell, etc.) with typical full scale voltages of only 20 to 100 millivolts will
require the addition of the VA-1 instrumentation amplifier when connecting to the ADC. Signal levels this low may
require shielded twisted pair wire. The shield should be left disconnected at the source and grounded to an earth
electrical ground at the VA-1.
CONNECTION OF DIFFERENTIAL SIGNALS TO THE VA-1: If low level differential inputs are required, the VA-1
may be used to convert a differential signal into a 0 to 5 volt signal for connection to the ADC. The VA series
amplifiers have a reference input (for connection to the ADC reference) which is used to generate a 2.5 volt offset
(adjustable). The gain adjustment on the VA series amplifiers may be adjusted to allow for differential signals as low
as (+) and (-) 5 millivolts or as high as (+) and (-) 5 volts. Using the VA-1 will allow the use of all 4 single ended inputs
on the ADC-4DU8 since the low level differential input to the VA-1 is converted to a single ended signal for connection
to the ADC-4DU8.
DIFFERENTIAL ANALOG INPUTS
The ADC-4DU8 may be set to accept (2) fully differential inputs in place of the (4) single ended inputs. The differential
voltage input range is determined by the reference input as shown on the previous page. The differential input signal
connects to terminals 1 and 2 for differential channel 1 and terminals 3 and 4 for differential channel 2. The ADC-
4DU8 also allows for (3) differential inputs if such inputs may be connected using a common negative (all of which are
connected to terminal #4). The positive differential inputs are then connected to the #1, #2 and #3 terminals (as
shown below). A third configuration allows for (2) single ended inputs along with (1) differential input. The single
ended inputs are connect to GND and terminals #1 and #2 and the differential input is connected as shown below*
(#3 and #4 terminals).
DIFFERENTIAL ANALOG INPUT TERMINAL BLOCK CONNECTIONS
Page 9
USB
1
2
3
4
differential input #1 + (Terminal 1)
differential input #1 - (Terminal 2)
differential input #2 + (Terminal 3)
differential input #2 - (Terminal 4)*
Default Differential
Analog Connections
GND
3.3V 5V REF+
GND
Reference
Select
Reference
Input
3.3V 5V

HIGH VOLTAGE INTERFACING
CAUTION: When working with high voltages, the potential for fire, explosion, electrocution, eye injury or blindness
and life threatening injuries or death exists. If you are not familiar with the precautions needed when working with
high voltages, do not attempt to connect high voltage up to these circuits. To prevent the danger of a high voltage
feeding back to the ADC and the fire/injury/electrocution hazard caused by an open or short circuit, 10 volt 2 watt
zener diodes and a 1/4 amp fuse should be connected as shown in figure E. Wire used to interconnect a high voltage
input must be rated for use with the higher voltage. When connecting the ADC to high voltage AC equipment the
method shown in figure D above is recommended.
The following method is used to divide a high voltage down to the 5 volt range needed for input into the ADC. This
method involves the use of two resistors (R1 and R2) which together add up to Rt (total resistance). The total
resistance is determined by using the Ohms Law to compute the resistance needed for a 1 milliamp current flow
through the resistors. EXAMPLE: If your full scale voltage is 100 volts (R = E divided by I) 100 volts divided by .001
amp = 100,000 ohms (100K ohm). To determine the proper ratio, divide 5 volts by the full scale voltage. 5 divided by
100 volts = .05. Multiple this ratio by the total resistance to determine the value of R2. R1 is then equal to the
difference between the total resistance and R2. EXAMPLE: ratio .05 times total resistance 100,000 ohms = 5,000
ohms (the value of R2). Total resistance 100,000 ohms less R2 5,000 ohms = 95,000 ohms (the value of R1). To
determine the power rating needed for the resistor, use the following formula: P = I squared times R. EXAMPLE: .001
squared = .000001 times R1 95,000 ohms = .095 watts. A 1/8 or 1/4 watt resistor would be sufficient.
Page 10
Fuse or Limiting Resistor (330 ohm 1 watt)
1 Amp Diode (50 volt)
AC Primary Voltage
120, 277, 480 etc.
(-)
6 or 12 Volt
Secondary
100 mf
35 volt
24 ga Communication Cable
To Analog
Input
To Analog
Input
(+)
(-)
1/4 Amp Fuse
Diode
(+)
High Voltage
AC/D C Input
(-)
Ground for
Safety
R1
R2
(1 ma maximum current
through resistors)
(+)
R1
R2
100 mf
35 volt
+
FIGURE C
FIGURE D
Switch or Relay
Contacts etc.
(Reference +)
To Analog Input
(+)
10 K ohm
(Reference -/Analog Ground)
DIGITAL INPUT
(0=OFF)
(255=ON)
FIGURE A
(Reference +)
(Reference -/Analog Ground)
To Analog
Input
POTENTIOMETER
MOVEMENT SENSING
FIGURE B
Ref (-)/Analog Ground
To Analog Input
Ref (+)
27K Ohm
Cadmium Sulfide
Photo Cell
+
10 mf Tantalum Capacitor
USING AN ANALOG INPUT
FOR ON/OFF STATUS MEASURING LIGHT LEVELS
FIGURE E
10K OHM
TYPICAL
IMPORTANT: The full scale voltage used should be the highest possible voltage that could be present at the high
voltage input.
AC voltages may be applied to the high voltage input if a diode is connected in series and a filter capacitor (100 mf,
35 volt typical) is connected between the ADC analog input and the ADC reference (-). AC voltages over 24 volts or
great enough to create an electrical shock hazard or fire should be connected to the ADC analog input using a step-
down transformer to reduce the high voltage down to the 5 volt range as shown in figure D. A diode and filter
capacitor must be connected on the secondary side of the transformer (a common low current power transformer
may be used).
CONNECTING SENSORS TO THE ADC-4DU8
A large variety of sensors, transducers, load cells and other devices that provide an analog output may be connected
to the ADC-4DU8. Most types of sensors may be located up to 1,000 feet from the ADC-4DU8. Pull up resistors may
be installed on the underside of the ADC-4DU8 for 2 wire sensors that receive power from the USB port. The cable
used to connect sensors to the ADC-4DU8 should be twisted pair or shielded twisted pair to suppress environmental
noise. Low cost CAT 5 cable works well when multiple sensors are in the same location.
MOUNTING
The ADC-4DU8 Analog to Digital card may be mounted in an enclosure (part # EN-C or EN-D) or on a metal
mounting panel using the MT-1 stand-off mounting hardware as shown below. The ADC-4DU8 will attach to the 4
stand-off spacers using 4-40 machine screws (4 mounting holes are provided on the ADC-4DU8). Contact technical
support for more information on mounting panels and various mounting layouts.
Page 11
ADC-4DU8
+
-
+
-
Twisted Pair
Pressure
Transducer
Power
-
+
ADC-4DU8
+
-
+
-
Twisted Pair
2 wire
temperature
sensor
ADC-4DU8
SIDE
VIEW
1/2" Stand-Off
1/4" 4-40 Machine Bolt
1/4" 4-40 Machine Bolt
MP-C
Mounting Panel
with MT-1
Stand-Off Kit
10 Volt 5 Watt
Zener Diodes

SETUP FUNCTIONS
RAW ANALOG DATA
The ADC-4DU8 will
present the raw analog
data as a number between
0 to 255 (8 bit) when in
single ended mode and a
number between
-128 to +127 (8 bit)
when in differential mode.
Relay and Input labels
may be changed by
clicking the Relay Control
or Input Setup buttons.
Click the Analog Setup
button to make changes to
the analog labels, suffix,
scale, offset or precision.
These also apply to
logged data.
NOTE: Once a change is made, the Apply Button will appear. Changes will not be applied until you click the Apply
button. The changes are saved to the adc4du8.ini file.
To completely automate the ADC-4DU8, check Start Minimized, Driver Only and Allow External
Commands. In this mode of operation, your program has complete control of the ADC-4DU8 and the User
Interface does not open. *do not check unless the ADC-4DU8 is always connected to a USB port.
**the default sample rate is 250ms (4 times per second). This is the rate at which all analog inputs are updated.
Page 12
Load Driver Only
and show Tray
Icon when Driver
Loads
Driver Auto Loads
on System Start*
Rate at which
Analog Inputs
are Updated**
Start the data logger by
checking the Enable
box. The logger will roll-
over or stop based on
the setting in the Max
Entries box. The Data
Interval may be set to
minutes or seconds and
will log the data based
on the setting in the box.
Click to Refresh
Com Ports (use the
pull-down to select, then
Apply to set)
ELECTRONIC ENERGY CONTROL, INC.
14960 Maple Ridge Rd
Milford Center OH 43045-9016
USA
[phone]
[phone]
[phone]
[email protected]
http://www.eeci.com
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