Operating steps of discrete resistor verification test system

Figure 1 is a block diagram of a resistor production test system based on a 2400 digital source meter, which is used to continuously feed resistors and calibrate them.

Figure 1
Resistor Production Test System Based on Model 2400 SourceMeter

Note that the resistor is placed in a test fixture, which is connected to the Model 2400 SourceMeter. When triggered, the Model 2400 SourceMeter outputs a signal and measures the resistor. These test results are then compared to pre-specified limits set in the instrument and a pass/fail decision is made. The Model 2400 SourceMeter digital I/O port sends a signal to the device sorter to quickly sort the resistor. The Model 2400 SourceMeter is able to communicate directly with the device sorter so that the computer can "sneak in" to download and store test data during sorter control operations while new resistors are placed in the test fixture. The

following algorithm describes the steps involved in the operation of the test system. It assumes continuous feed operation with only one resistor in the test fixture at a time.

1. The operator instructs the PC that a reel of resistor products is in place and ready for testing.
2. The PC starts the Model 2400 SourceMeter operation.
3. The Model 2400 SourceMeter Instrument waits for a “Test Start” trigger from the sorter.
4. When the first resistor is in place, the sorter sends a “Test Start” trigger to the Model 2400 SourceMeter Instrument, indicating that the first resistor is ready for testing.
5. The Model 2400 SourceMeter Instrument verifies the resistors according to the test sequence stored in the source memory, makes a pass/fail decision, and saves the data for each test: tolerance band and voltage coefficient.
6. The Model 2400 SourceMeter Instrument sends the overall pass/fail status and “Test End” signal to the sorter, and sends the test data to the PC (in parallel).
7. Repeat steps 3 to 6 above for the remaining resistors in the reel or tube.
8. The Model 2400 SourceMeter Instrument returns to the idle state. A new resistor reel is placed in the sorter.
9. The operator indicates to the PC that a new resistor reel is in place.
10. Repeat steps 1 to 9 as needed.