Data Acquisition & Control Specifications

Data Acquisition & Control

Let DPP show you how to interface to a computer.

System Overview:

DA&C stands for Data acquisition & Control. It uses the printer port to send eight (8) outputs CONTROL lines from the PC parallel printer port to the project board. It receives five inputs lines from the project board back to the PC via the parallel printer port. The project board contains output latches, Input buffers. A/D converter (Analog to Digital Converter), Operational Amplifier, wheatestone bridge, Current meter, and a Solar cell.

There are three main experiments available for the DA&C project.

Experiment #1. IC tester - tests OR, NOR, AND, NAND, XOR logic gates. The program sends eight control lines to the IC that is plugged into socket # 2 of the project board, and receives a feedback from socket #2 back to the PC.

For experiments #2 & #3 the program uses an A/D converter to digitize the analog signals that are produced by the Operational Amplifier. A wheatestone bridge balances the amplifier. The Solar cell and the strain gauges sensors are connected to the bridge via a selector slide switch.

Experiment #2. Light intensity tester - measures light intensity and displays it with an external current meter (at the project fixture) also, the program displays a software simulated current meter and then plots a graph of intensity verses time.

Experiment #3. Pressure tester - measures the pressure exerted on a metal bar and displays it in the software with a pressure meter and plots a graph of pressure verses time.

Experiment #1 - IC tester.

	Slide switch A to position #1
	Insert a logic gate that you wish to test into Socket 2 of the project board.
	Click on the IC tester icon
	Click on the desired IC logic gate to test:

	AND
	OR
	NAND
	XOR

Click on the input pins of the IC and observe the output as it changes.

	Red = digital 1
	Black = digital 0.

Experiment #2. Light Intensity Tester.

	Slide switch A to position 2.
	Slide Switch B to position 2.
	Select the light intensity option from the selector (right option.)
	On the project board select S3 and slide it to ON position (range selector for room ambient light intensity.) Cover the solar cell and adjust on the project board the zero level for the external meter.
	Uncover the solar cell and adjust Max level for the external meter.
	Click to view the simulated current meter.

In order to adjust the simulated current meter in the program you must follow the next 2 steps:

DC bias battery adjustment.
Wheatstone bridge balance.

1. Battery bias adjustment.

Background: The DA&C is using a single 9 volt battery which provides approximately 12 hours of continues use. The battery intensity and voltage level varies as its usage time progresses.

	Click to view the 8-output control lines
	For new battery click on the right arrow until output ports 1 to 4 are reds (digital 1.)

As the battery becomes progressively weaker a smaller DC bias shall be needed.

The user can identify it if any difficulty shall arise in the next adjusting step thus, reduce the bias level.

	Click on the start icon to start the acquisition of the light intensity.
	Uncover the solar cell and adjust the software-simulated meter and the graph level using the balance (white) potentiometer to about 80%-90% of maximum level.
	Cover the solar cell and observe how the simulated meter and the graph changing.

The light intensity experiment enables you to perform various interesting scientific experiments. For example it can measure also the invisible frequency in the light spectrum such as for example infrared. You may try to aim your TV remote control and observe and study the reaction. DPP engineering has available an infra red modulated microphone. It modulates the intensity of an infra red light based on a voice level. The DA&C project can record it and then replay it and reproduce the audio sound.

Additional light intensity experiments that can be performed with the DA&C project are:

Color recognition. (Using a carton tube and red + green + blue filters)
Polarized light intensity. (Using Polaroid filter) notes by Dr. James Frost and his NASA’s research on "polarized light and stars" will be available (exclusively) from DPP Engineering by 9/97.)
Star light intensity. (Using a telescope (kit) for an additional fee of $30.00.)

Experiment #3. Pressure tester

	Slide switch A to position 2
	Slide switch B to position 1
	Click on the left button of the selector for pressure
	Click on the left arrow to adjust the output port status to all blue (digital 0.)
	Click to start the data acquisition of the pressure.
	Adjust the simulated pressure meter and the graph using the balance (white) potentiometer to about the middle of the meter range.
	Bend the metal bar and observe drag and lift.

Additional experiments can be performed using the DA&C pressure measurement:

Wind Tunnel. An inexpensive way to measure the lift and drag of a car or a wing that is attached to the pressure bar. Use a fan to blow wind inside an enclosure.
An inexpensive way to measure a Car crashing impacts.
An inexpensive way to measure the pressure on a bridge structure.

^{Installation
Instructions

Run setup from the CD_ROM or Floppy disk # 1 to install the
DA&C software. (If you read this in your program's help file then you have already
installed the software.)
Connect the DA&C-II interface to the parallel printer port. If
your computer has only one printer port, you may need to disconnect your printer and use
the cable for the interface.)
Turn power on at the interface board, and click the mouse on the
port test icon to let the program detect to which parallel printer port (LPT#) the
interface is connected to.

Buttons &
Functions

Select
Project Name (should be selected before you start the project)

To Record a
graph.

To Start the
DA&C and make it ready for the next test.

To Replay a
recorded graph from memory.

To select the
graph(s) to be displayed.

To Reset the
graph to time = zero.

Superimpose
option. It provides multiple color graphs. Thus, a comparison between a real time graph
acquisition versus a previously recorded graph is possible.

To filter
noise that may put jitters on the graph.

To view range
and domain setting (move the bar graph) and observe new ranges.

To view the
status of the 8 parallel lines outputs (red -1, blue - 0.)

To view the
IC tester

To view the
software simulated meters.

To Toggle
ON/OFF the background music.

To let the
program detect to which printer port (LPT#) is connected to.

To Read About
the program.

To Exit from
the program.}

**System Requirements:**
IBM PC compatible
CPU: 486- 66 MHz or faster.
VGA Monitor
Parallel Printer port
Windows 98, Windows 95 Or Windows 3.1

**Package List:**
1. DA&C interface PCB.
2. Solar Cell.
3. Strain gauge unit.
4. Assorted I.C. for testing.
5. 1MA current meter
6. Folder with Instructions, software on CD-ROM and on floppy disks.