160 likes | 273 Views
Physics 434 Module 1. About the computers: You can save VI’s on the local disk. put them into My Documentsyour_name (But beware: no backup, no protection) Or just use catalyst for temporary storage! Review of last week – some important LV lessons
E N D
Physics 434 Module 1 • About the computers: • You can save VI’s on the local disk. • 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, graphs • Right-click! • 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, upto 8 measurement channels, also 10 V. • Wire a simple circuit on a breadboard • Layout guidelines • Oscilloscope, DVM auxiliary tools Physics 434 Module1A
The Pretest:-introduction to the circuit -diagnostic for us (written by Mac Stetzer of PEG) Physics 434 Module1A
The “voltage divider” circuit ach0 dac0 ach1 R1 = 100 R2 = 200 Physics 434 Module1A
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
The PCI-MIO-16E-4 board Computer Breakout-box Physics 434 Module1A
Differential input Physics 434 Module1A
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
Testing: get the testio vi • Click on the calendar entry; 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. Physics 434 Module1A
Procedure for this week • Set the test mode of the test_io VI to produce outputs according to your expectation for the first pretest question. • Revise the VI so that you can generate a graph like the one you sketched (see the graph example in graphdemo vi, or examine fig 8.17.) • 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! Physics 434 Module1A
Example layout ach0 ach1 daco Physics 434 Module1A
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 • Use reference material • Ask a staff member 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 Module1A
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.
Next week’s circuit The IRF511 power MOSFET Transistor. Set the voltage here… And measure the voltage and current here Physics 434 Module1A