1. Introduction
The DSO FNIRSI-150 is a fully assembled digital oscilloscope designed for ease of use and reliability in circuit operation. It features an ARM Cortex-M3 processor (STM32F103C8) and a 2.4-inch color TFT display. This device is capable of displaying various waveform parameters, including frequency, period, pulse width, duty ratio, maximum, minimum, average, peak-to-peak, and virtual values. While originating from a DIY kit design, this version is provided fully assembled and ready for immediate use.
2. Package Contents
Please check the package for the following items:
- 1 x Fully Assembled DSO FNIRSI-150 Digital Oscilloscope
- 1 x BNC to Alligator Clip Probe
- 1 x User Manual (English)
3. Setup
- Power Connection: Connect a DC 9V (8-10V) power supply to the DC input jack on the side of the oscilloscope. Ensure the power supply polarity is correct.
- Power On: Flip the ON/OFF switch located on the side of the device to the 'ON' position. The display should light up.
- Probe Connection: Connect the BNC end of the provided probe to the BNC input connector on the oscilloscope.
- Probe Calibration (Optional): The oscilloscope features a 1KHz test signal output. To calibrate the probe, connect the probe's alligator clip to the 1KHz output terminal (usually labeled '1KHz' or similar) and adjust the probe compensation if necessary to achieve a clean square wave on the display.
4. Operating Instructions
The DSO FNIRSI-150 offers intuitive controls for waveform analysis:
4.1. Basic Controls
- V/DIV Button: Adjusts the vertical scale (volts per division).
- SEC/DIV Button: Adjusts the horizontal scale (time per division).
- TRIGGER Button: Cycles through trigger modes (Auto, Normal, Single).
- ADJ Knob: Used for fine adjustment of parameters, such as trigger level or waveform position.
- OK Button: Confirms selections or activates functions.
4.2. Trigger Modes
The oscilloscope supports the following trigger modes:
- Auto: Automatically triggers the waveform, even without a stable signal.
- Normal: Triggers only when the signal meets the set trigger conditions. Useful for stable, repetitive signals.
- Single: Captures a single waveform event and then stops. Ideal for non-repetitive signals.
You can also select rising or falling edge trigger and observe previous waveform before trigger (negative delay).
4.3. Waveform Display and Analysis
- Parameter Display: The screen displays digital values for frequency, period, pulse width, duty ratio, MAX./MIN./AVG./Peak-Peak/virtual values of the waveform.
- HOLD Function: Press the appropriate button (refer to on-screen prompts or specific manual for your device) to freeze the waveform display at any time for detailed analysis.
- Waveform Storage: The device includes a waveform storage function, ensuring that the displayed waveform is not lost after power off.
4.4. Coupling Modes
The oscilloscope supports DC, AC, and GND coupling modes:
- DC Coupling: Displays both AC and DC components of the signal.
- AC Coupling: Blocks the DC component and displays only the AC component of the signal.
- GND Coupling: Disconnects the input signal and displays a ground reference line, useful for checking the zero level.
5. Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the oscilloscope. Do not use abrasive cleaners or solvents.
- Storage: Store the device in a cool, dry place away from direct sunlight and extreme temperatures.
- Handling: Avoid dropping the device or subjecting it to strong impacts.
6. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No display after power on | No power, faulty power supply, or device fault. | Check power supply connection and voltage (DC 9V). Ensure the ON/OFF switch is in the 'ON' position. |
| No signal displayed | Probe not connected correctly, no input signal, or incorrect V/DIV/SEC/DIV settings. | Ensure probe is securely connected to both the oscilloscope and the circuit. Verify the circuit is active. Adjust V/DIV and SEC/DIV settings. Check trigger level. |
| Unstable waveform | Incorrect trigger settings or noisy signal. | Adjust the trigger level using the ADJ knob. Try different trigger modes (Auto, Normal). Ensure a stable signal source. |
| Incorrect waveform readings | Improper probe compensation or incorrect coupling mode. | Perform probe calibration using the 1KHz test signal. Select the appropriate coupling mode (DC/AC). |
The device also features short-circuit and open-circuit detection, which can be useful for diagnosing issues if you are working with the internal components or if the device was previously a kit.
7. Specifications
| Feature | Specification |
|---|---|
| Processor | ARM Cortex-M3 (STM32F103C8) |
| Display | 2.4-inch Color TFT |
| Maximum Real-time Sampling Rate | 1MSa/s |
| Analog Bandwidth | 0-200KHz |
| Sensitivity Range | 5mV/div - 20mV/div |
| Maximum Input Voltage | 50Vpk (1X probe) |
| Input Impedance | 1M ohms / 20pF |
| Accuracy | 12 Bits |
| Record Length | 1024 points |
| Coupling Modes | DC / AC / GND |
| Time Base Range | 500s/Div - 10us/Div |
| Trigger Modes | Auto, Normal, Single |
| Trigger Position | Center of Buffer |
| Supply Voltage | DC 9V (8-10V) |
| Current Consumption | ~120mA @ 9V |
| Main Board Size | 94 x 65mm / 3.7 x 2.56in |
| Analog Board Size | 65 x 47mm / 2.56 x 1.85in |
| Screen Size | 52 x 40mm / 2 x 1.57in |
| Package Weight | 179g / 6.33oz |
8. User Tips
- Start Simple: If you are new to oscilloscopes, begin by testing known signals, such as the built-in 1KHz test signal, to familiarize yourself with the controls and display.
- Probe Safety: Always ensure the probe is securely connected before taking measurements. Be mindful of the maximum input voltage to avoid damaging the device.
- Understanding Scales: Pay close attention to the V/DIV and SEC/DIV settings. These determine how the waveform is scaled on the screen and are crucial for accurate measurements.
- Trigger Level: Adjusting the trigger level is key to getting a stable waveform display. Experiment with the ADJ knob to find the optimal setting for your signal.
- Secondary Development: For advanced users, the ARM Cortex-M3 processor allows for secondary development, potentially transforming the device into a millivoltmeter or data logger.
9. Warranty and Support
This product is covered by a standard manufacturer's warranty against defects in materials and workmanship. For technical support, troubleshooting assistance, or warranty claims, please contact the seller or manufacturer directly. Keep your purchase receipt as proof of purchase.
