1. Introduction
For this constructions I was inspired LPTScope from Bojan Banko. I build a new hardware and modify software with permission from author.
This construction is free for personal use, for commercial use you need permission from author (from author original software too).
2.Technical statements
Supply voltage ~9 - 15V
Input voltage DC/AC (peak to peak) 0,2V; 0,5V; 1V; 2,5V; 5V; 25V
Max. input voltage 100V
Input resistance 1MW
Maximal sample rate theoretical 600kHz
practical 300kHz
Vertical shifting of zero -10% to +60% input range
Setting up of trigger 0 to 100% input range
Connection to PC bidirectional LPT port
3.Circuit
For A/D converter I use TLC0820 with protection resistors R1-R8. Input circuit created voltage divider 1:5 with switch PR1.
Switch PR3 set up zero for input and switch PR4 set up measure of AC/DC signal.
Input amplifier is created IO2A. Switch PR2 set up amplify 1:1, 10:1 and 25:1. Summary amplifier is created IO2B and shifting zero for measure AC signal.
Potentiometer P2 and IO2D set up trigger.
The oscilloscope use several stabilized DC voltages +5V (IO5), +9V (IO3), -9V (IO4).
4. Mechanical design
For construction is used one side PCB with several connection wires (layout chart of components). For oscilloscope is used box U-KM26, see figure 1 - 2 - 3.
5. Setting up
First you install supply part inclusive of K3. You check on voltage +5V, +9V, -9V. Now you install IO2 and all components except IO1 and check function. If it is all right, you can install IO1 and resistors R1-R8 (SMD).
You must set LPT1 on bidirectional or ECP or EPP in BIOS and then connect oscilloscope to LPT1 port PC.
6. Software LPTScope
Program is freeware, included source code.
If you connect hardware for the first time, you start measurement - pres button "Run". You should to see horizontal black line. Line have vertical shifting, when you turning potentiometer P1. When line not shifting, you must set regular reading from A/D converter (press button AD on toolbar) by means of set up number waiting cycles. You turning potentiometer P1 and look at voltmeter. You must see stable data and data must react to turning potentiometer. Regular reading you check up on to signal applied to input.
One record - activate measure, after buffer is full, measure be stoped
TRG INT - internal software trigger
TRG EXT - internal hardware trigger from input signal. You can modify hardware to external trigger
Violet line - shifting zero of input signal. When is negative shifting, negative voltage not display (it display as zero).
Use mouse - when you press left button, you can movie mouse and you will see voltage (Y axis) and time and frequency (X axis)
Time base - set scale on axis X
Y base - set scale on axis Y
Oscilloscope input correction - for right display input voltage (input range)
Sampling rate - setting up when set number waiting cycles for reading from A/D converter
Sample buffer - for saving data from A/D converter. Use max 10000 for oscilloscope and max 1000000 for One record mode
You can see max 32000 points on the screen. When sample buffer is bigger and you want to see whole buffer, you must set bigger Time base = 32000/(Sampling rate * Sample buffer).
Download LPTScope version 1.3
Download source code
7. Components list
Electrolytic capacitors
C1,C2 220 uF/25V
C3,C4,C6,C7 47 uF/16V
C5 100 uF/25V
C23 22uF/16V
Ceramic capacitors
C8, C9,C10,C11,C12,
C13,C14,C15,C16 100 nF
C18,C17 22 pF
C20 12 pF
C21 47 pF
Plastic capacitors
C19 100 nF/250V
C22 100 pF/250V
Diode
D2,D1 1N4005
D3,D4,D7 BAT48
D5,D6 1N4148
ZD1 BZX83V5,6V
ZD2,ZD3 BZX83V10
ZD4 BZX83V5V1
Integrated circuit
IO1 TLC0820
IO2 TL074
IO3 78L09
IO4 79L09
IO5 78L05
Connectors
K1 CAN25VP
K2 BNC-Z 50RW
K3 SCD-016
Inductors
L2,L1 220 uH
Switches
PR1,PR3,PR4 P-B143
PR2 P-GS373
Potentiometers PC 1221N
P2,P1 10k
Resistors SMD 1206
R1,R2,R3,R4,R5,R6,R7,R8 680
Resistors 0,4W
R9 1k
R10,R11 100k
R12 120k
R13 680k
R15,R20,R21,R22,
R23,R24,R25 4k7
R16 470
R17 56
R18 180
R19 15
R26,R30 10k
R27 15k
R28 22k
R29,R31,R33 10k
R32 8k2
Resistors 2W
R14 10k
No comments:
Post a Comment