tailieunhanh - Industrial Control Student Guide Version 1.1 phần 3

Đơn giản chỉ cần gọi cho một số Ủy Quyền Return Merchandise (RMA), ghi số trên bên ngoài của hộp và gửi nó trở lại để Parallax. Xin bao gồm tên, số điện thoại, địa chỉ vận chuyển, và mô tả của vấn đề. Chúng tôi sẽ trả lại sản phẩm của bạn, hoặc thay thế của nó, sử dụng cùng một phương pháp vận chuyển được sử dụng để vận chuyển các sản phẩm để Parallax. | Experiment 2 Digital Input Signal Conditioning Figure and b Retro-reflective Switch Pictorial and Schematic Industrial Control Version Page 49 Experiment 2 Digital Input Signal Conditioning Adjust the potentiometer to provide the proper reference voltage which is halfway between the measurements. Testing the output of the LM358 should result in a signal compatible with the BASIC Stamp. The output should be low with no object and high when the white object is placed in front of the emitter detector pair. Measure these two output voltages of the LM358 and record the values in Table . If the output signal is compatible apply it to the BASIC Stamp s Pin 3. Detecting light reflected by an object is called retro-reflective detection. Table LM358 Values Condition Phototransitor Voltage LM358 Output Voltage No object - no reflection Object - full reflection Reference voltage setpoint This ability to yield a switching action based on light received lends itself to many industrial applications such as product counting conveyor control RPM sensing and incremental encoding. The following exercise will demonstrate a counting operation. You will have to help though by using your imagination. Let s assume that bottles of milk are being transferred on a conveyor between the filling operation and the case packer. Cut a strip of white paper to represent a bottle of milk. Passing it in front of our switch represents a bottle going by on the conveyor. Only a slight modification of the previous program is necessary to test our new switch. If you have Program loaded simply modify the first button instruction by changing the input identifier from Pin 1 to 3. The modified line would look like this Program modification to Program for the retroreflective switch input BUTTON 3 1 255 0 Wkspace1 1 Count it Debounced edge trigger detection of optical switch Programming Challenge 2 Milk Bottle Case Packer Refer back to Experiment 1 and consider the conveyor diverter