1 Physics 434 Module 1 Reminder about the computers: –You can save VI’s on the local disk. put them on the desktop put them into My Documents\your_name (But beware: no backup, no protection) –Or just use catalyst for temporary storage! Review of last week – some important LV lessons –Controls, indicators, while (and for) loops –Right-click! (I’m a Mac user so I always forget this.) You’ll also start picking up shortcuts, e.g., –Tool options: auto, menu, or tab –Cntrl-b (remove bad wires, with care) –Cntrl-z (undo) –Shift-right-click: bring up the tool menu Physics 434 Module1A

The next two weeks Introduction to DC I/O capability of the PCI-E board and use of the break-out box –  10 V out, up to 8 measurement channels, also  10 V. Wire a simple circuit on a breadboard –Layout guidelines –Oscilloscope, DVM auxiliary tools 2Physics 434 Module1A

The “voltage divider” circuit. The single most important circuit. 3 dac0 ach0 ach1 Physics 434 Module1A R1 = 100  R2 = 200 

4 Properties of the “DAQ” board –up to 16 input channels, multiplexed to a 12-bit ADC (we use four, configured as two differential) –2 output channels (2 12-bit DACs) (we use one) –Questions: what does 12-bit mean? Linear A vs. D: but what are the offset and scale factors? Can you control them? Differential vs. single-ended? Physics 434 Module1A

5 The PCI-MIO-16E-4 board Breakout-box Computer Physics 434 Module1A

6 Differential input Physics 434 Module1A

7 Wiring to be done to the “Breakout box” Differential inputs: red/black pair to BNC –Input channel 0 (ach0): ACH0/ACH8 [68/34] –Input channel 1 (ach1): ACH1/ACH9 [33/66] –(beware touching the BNC connector to anything) Output: two wires long enough to reach breadboard –Output channel 0 (dac0): DAC0/A0GND [22/55] Note that while the inputs are “floating”, the output is not: it is relative to ground. Physics 434 Module1A

8 Testing: get the testio vi copy Module1.llb to your space; open it, then the vi test_io We rarely build vi’s completely from scratch: this is a framework, around a custom vi to do the I/O Physics 434 Module1A

Features of the test framework Knobs, dials for the input, two outputs A special test mode – an important feature for experimental design I/O put into a special sub-VI with three “frames” –Set dac0 using a DAQ assistant –Delay (default 0) (allow system to adjust to change) –Read ach0 and ach1 with another DAQ assistant. –All set for -10 to +10 volts: you may want to change later. 9Physics 434 Module1A

Procedure for this week Set the test mode of the test_io VI to produce outputs according to your expectation. Revise the VI so that you can generate a graph like the one in graphdemo vi (also see figure 8.19 in text). Wire up the board with the two resistors, and make connections to the breakout board, to correspond to the question. Neat layout is very important, for you to understand, and for us to help! 10Physics 434 Module1A

Example layout 11 daco ach0 ach1 Physics 434 Module1A

12 Hints VI: keep neat, use labels and add comments Test each piece first! You can have separate vi’s Breadboard: Lay out the circuit neatly: use the space If appropriate, test the circuit with power supply, DVM or scope before trying to run the VI. Keep good notes: a personal lab book is best Problem: Use reference material, help files, etc. More problems: Ask the TA Physics 434 Module1A

Requirements for the VI Sweep through predefined set of values for setting V0 (perhaps a for loop) Record values for V1 and V2 for graphs and analysis, using either or both experimental or test modes. Plots: –V1 and V2 vs. V0: the data and your expectation (test mode) perferably on the same graph, each labeled (so 4 graphs on the same plot) or two plots) –V2 vs. V1 (as in the pretest) Analysis: –Discuss the graphs and comment on the results –Measure and comment on the ratio V2/V1 and the sum V2+V1. (You may want to have plots or at least some measurements) Physics 434 Module1A13

Turning in your VI(s) Operate | Make current values default – needed to record your results by saving the graphs File | VI properties | Documentation: write a little report, containing your name(s), purpose of the VI, implementation features, conclusions. Submit multiple VIs in an llb, like Module1. 14

15 Next week’s circuit (you may need to remind yourself how a FET works) Set the voltage here… And measure the voltage and current here The IRF511 power MOSFET Transistor. Physics 434 Module1A