Файл: Industrial Control (Students guide, 1999, v1.1 ).pdf

Appendix A: StampPlot Lite

Data from the BASIC Stamp is processed in one of four ways by the application: Analog Values

Any string sent beginning with a numeric value will be processed as an analog value and graphed.

Digital Values

Any string sent beginning with '%' will be processed as digital values. A separate digital plot will be started for each binary value in the string. For example, "%1001" will plot four digital values. Up to a 9-bit value may be sent. Once digital plots are started, caution should be used to always send the same number of bits since the plots are position-order dependent.

Control Settings

Any string beginning with '!' will be processed as a control setting. The various settings of the application may be controlled from the BASIC Stamp using specified control words and values, if required.

Other Strings

All other strings simply will be added to the running message list box.

Debug "Hello world!",13

Note that each instance of data MUST end with a carriage return (13 or CR).

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Appendix A: StampPlot Lite

The steps for using BASIC Stamp programs with StampPlot Lite are as follows:

1.Start StampPlot Lite through your Start/Programs/StampPlot/StampPlot Lite icon.

2.Enter and run your BASIC Stamp program from the BASIC Stamp editor.

3.Close the blue BASIC Stamp debug window by clicking on the “close” box.

4.Select the COM port and click 'Connect' checkbox.

5.Click the 'Plot Data' checkbox.

6.Some programs may require you to reset the Board of Education (BASIC Stamp) to catch initial configuration and control settings. Do this by pressing the Reset button on the board.

7.Prior to downloading (running) another program to the BASIC Stamp, be sure to uncheck the StampPlot 'Connect' checkbox or your COM port will be locked by StampPlot Lite.

The plot will acquire analog and digital data and store it temporarily so that it may be resized or shifted on the screen. The number of data points collected is adjustable. Once the data points reach maximum, the plot must either be stopped or reset.

The following program will perform some configuration settings, continually plot and display the value of X on StampPlot, and plot the four digital bits of the value of X. Enter the program and use the steps above to test it with StampPlot Lite.

'Appendix A Program, StampPlot Example

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Appendix A: StampPlot Lite

Below is a screen shot of StampPlot Lite showing the above program plotted.

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Appendix A: StampPlot Lite

Tool Text Help

If a copy of StampPlot Lite is running on your computer, you may place the cursor over each control for 'Tool Text Help.’ The following is a brief summary of each control. The BASIC Stamp programmable command, where applicable, is in brackets:

Top Section: General Controls

•Com 1: Drop down to select the applicable COM port.

•Connect: Connects the application to the selected COM port.

•Plot Data: Allows plotting of incoming data. Deselecting this control will stop the plotting of data but will allow messages and other actions to continue. [ !PLOT ON/OFF]

•Reset: Clears the plot, resets to time 0, clears minimum and maximum value (optional). [ !RSET ]

•Stop Plot: When maximum data points are reached, the plot stops (Plot Data becomes unchecked). [!MAXS ]

•Reset Plot: When maximum data points are reached, the plot resets. [ !MAXR ]

•User Status: (showing "The value of X is 9") Optional status messages from the BASIC Stamp may place data here. [ !USRS message ]

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Appendix A: StampPlot Lite

Left Section: Primarily for Setting the Analog Plot

•Span Drop-Down box: Allows a selection of pre-defined plot ranges. Use of the

BASIC Stamp command !SPAN will add a range to this drop-down. [ !SPAN minvalue, maxvalue ]

•+ and - buttons: Respectively double or halve the span. The minimum value does not change.

•Multiplier: Defines the amount incoming BASIC Stamp analog data will be multiplied by prior to plotting or saving to file. [ !AMUL value ]

•Save Data to File: Saves the incoming data to a text file in the application directory called "stampdat.txt.” If time stamping is enabled, each record will be marked with the current system time and the number of seconds since the last reset. The value of the data point for analog and digital values will also be recorded. Each record will have the following form:

-Time of day, seconds since reset, analog data point, analog value, digital data point, digital data value. Note that each record is comma delineated for importing into a spreadsheet, if desired.

-Note: Data is saved ONLY when ANALOG data arrives. To force saving when no analog data is recorded, debug a value such as zero ( DEBUG DEC 0, CR).[ !SAVD ON/OFF ]

•Delete Data File: Deletes "stampdat.txt.” If data saving is enabled, the file will be re-created after deleting it. [ !DELD ]

•Analog Minimum and Maximum values: These may be manually changed. Tab off, or click another

control, to set the new value. [ !AMIN value !AMAX value <or> !SPAN minvalue, maxvalue ]

•Time Stamp: Enables time stamping of messages and data to the file. It includes both the current time and seconds since the last reset. [ !TSMP ON/OFF ]

•Clear Messages: Clears the messages in the listbox. [ !CLRM ]

•Save messages to file: Saves messages to the file "stampmsg.txt" in the application directory. Messages will be saved the same way they appear in the message box. [ !SAVM ON/OFF ]

•Delete Msg file: Deletes "stampmsg.txt" in the application directory. If the "Save Messages…" is enabled, the file will be re-created. [ !DELM ]

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Appendix A: StampPlot Lite

Bottom Section: Plot Shift and Time Span

•The minimum and maximum times of the plot may be set manually. Tab-off or click another control to apply the value. [ !TMIN value and !TMAX value ]

•Scroll Bar: If the plot extends beyond the current limits, the scroll bar may be used to reposition the plot (if collecting data, Enable Shift must be on).

•Enable Shift: Allows the plot to shift automatically when maximum plotted time is exceeded. Also enables operation of the scroll bar when collecting data. Note: Shifting of the plot during data collection may cause time errors in the data as the plot refreshes. [ !SHFT ON/OFF ]

•+/-: Respectively doubles or halves the time span of the plot. The minimum value of the plot will not change.

Right Section: Plot Data

•Data Points: To allow the plot to be manipulated, data is stored in memory. The maximum number of points (either analog or digital) that may be recorded is the Max. ‘Current’ displays the current data point being stored. Once the maximum is reached, the plot will either reset or stop, depending on the configuration. [ !PNTS 1000 ]

•Last Analog Data: Displays the time since reset and the last analog value plotted.

•Plot Pointer: Moving the plot pointer on the display shows the current analog value and time for that point on the plot.

•Maximum: Records the maximum analog value and the time it was reached.

•Minimum: Records the minimum analog value and the time it was reached.

•Clear Min/Max: Clears the recorded minimum and maximum values. [ !CLMM

]

•Clear min/max on reset: Allows a reset to clear the minimum and maximum values. [!CMMR]

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Appendix A: StampPlot Lite

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Appendix A: StampPlot Lite

Display Control and Zoom

•Moving the cursor on the plot will set the plot pointer time and value to the current position.

•Double-clicking the plot will shift display modes from yellow to white background and thin lines to thick lines for better printing (ALT-Print Screen to capture form to the clipboard) and projected display.

•Shift-Click (hold) and Drag allows you to specify an area of the plot to zoom.

BASIC Stamp Control and Configuration Commands

The majority of the plot configuration and controls may be set from within the BASIC Stamp program. To use these commands, simply debug from the BASIC Stamp. All commands must end with a CR (ASCII 13): DEBUG "!PLOT ON", CR.

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Appendix A: StampPlot Lite

Additional Application Notes

The amount of the plot that is used is dependent on the number of data points and the rate at which they are transmitted. For example, if you wish 60 seconds of data to fill the screen and are transmitting from the BASIC Stamp at a maximum rate of 100 msec (Pause 100 + processing time): 60/.1 = 600 data points.

The application needs a minimum regular pause in the reception of data for complete processing. A pause of 10 msec is typically sufficient for a fairly fast computer. If the application senses it cannot keep up with incoming data, a message box will appear and the application will disconnect. Some indications that the computer cannot keep up are: garbled data, no plotting, and the inability to affect any controls (locks up).

The greater the number of data points and the higher the current data point, the longer the plot will take to respond to plot shifts as it redraws. For faster, reliable configuration from the BASIC Stamp on initial power up or resetting, the following is recommended:

•Pause for 500msec at the start to allow StampPlot's buffer to clear.

•Perform a StampPlot RESET (!RSET) prior to making configuration changes to allow the data points to be cleared so redrawing is not performed.

•Reset (!RSET) at the end of the configuration resets the plot to time 0.

As with any application, the best way to learn it is to play. Have fun!

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Appendix A: StampPlot Lite

Upgrade to StampPlot Pro for your Industrial Control experiments!

A few of the features include:

•Plotting of multiple analog channels.

•Saving of plots and images.

•Advanced logging features.

•Ability to draw graphics.

•PC based macros of instructions, including data manipulation.

•Interactive capabilities for adjustments on the fly.

This screen shot of StampPlot Pro shows the PID exercise in Experiment #7 plotting actual and setpoint temperature along with the %Drive (bottom bars).

The gain values may be entered in the data window to be read by your BS2!

A PC based macro shows the temperature in the thermometer.

Examples based on the Industrial Control text are posted in the on-line tutorials. Download and evaluate free!

http://www.selmaware.ccom/

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Appendix B: Fan Encoder Printouts

Appendix B:

Fan Encoder Printouts

These printouts are full size, and should be an ideal fit for your fan used as a digital switch in Experiment #2.

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Appendix B: Fan Encoder Printouts

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