A typical “hardware” standard

1. A typical “hardware” standard

2. How do computers control the world?

3. Each joint is a motor that can be turned on and off with a switch

4. 7 switches to control a whole robot

5. A Computer “port” • Connects 1 byte of memory to outside world

6. A printer “Port” • Computer connects an internal byte variable to the printer switches, and changes the values to tell the printer what to print

7. Address Data Memory r/w

8. I/0 Memory Data Memory Program Memory Fast Specialty Memory

9. Memory mapped I/O 8-bit Your Program Driver Port A Decimal Variable A Binary Value A function call

10. an example program Private Sub Write_Port(value As Integer) txtByteOut.Text = (value) 'decimal Status = cbUSBDOut(DeviceNum, RELAY_PORT, value) If value < 16 Then txtHexOut.Text = "0" & (Hex(value)) Else txtHexOut.Text = (Hex(value)) End If ' hex txtBinary.Text = CBin(value) 'binary End Sub

11. the overriding concern • the computer power levels (+/- 5, +/- 12) are EXTREMELY sensitive to surges • industrial machinery regularly injects surges into its power lines (+24 vdc) • computer power (clean) MUST be kept separate from industrial power (dirty) • reference pt (ground) is connected between the two in ONE PLACE ONLY

13. Optical Isolation

15. motor, etc

16. Computer “dirty” Environment

17. Mechanical Relay

20. Computer Environment

21. Digital Input

24. buying parts http://www.sparkfun.com