Multimeter testing and methods of detecting electrical faults
Regarding the method of multimeter testing and detecting electrical faults, using the multimeter to record intermittent faults, the multimeter to record intermittent faults continuously, the method of the multimeter to mark the recording time, etc., record the time when the minimum/maximum/average recording mode is activated, respectively.
How to use a multimeter to detect electrical faults
How to use a multimeter to test and detect electrical faults, it is difficult to capture the electrical parameters when the fault occurs, which adds great difficulty to the detection.
There are a number of test equipment that can make intermittent fault diagnosis simple.
These devices include sophisticated signal analyzers and digital oscilloscopes, as well as simple-to-use handheld multimeters, digital multimeters, and measurement recording power for basic measurement functions (AC voltage, DC voltage, and resistance measurements), through standard Combined with the table, the multimeter can detect the fault parameters of intermittent faults.
In the past, people used a mechanical tape recorder to continuously record voltage or current. During work, it was necessary to connect a voltage to the input, or clamp a current sensor on a wire, and the recorder would print the change in voltage or current on the tape. In some cases, the maximum length of the record depends on the amount of paper on the slip.
1. The multimeter records intermittent failures
Use the multimeter Min/Max/Average recording mode, select the corresponding Gongza according to the measurement item (AC Voltage, DC Voltage, Resistance, AC Current, DC Current and Frequency), make sure to connect before activating the Min/Max/Average function Test the circuit, otherwise the minimum reading will always be the ambient value before the test leads were not connected.
This affects the analysis of the recorded data after the recording time has elapsed j Activates the min/max/average logging mode, the maximum reading will be indicated on the multimeter display, and a beep will sound when a new maximum or minimum value is detected Voice.
Advantages: While ensuring that the DMM will not be tampered with and will not pose a threat to any man-made safety hazards, the DMM can be left in place to measure and focus on other tasks. At any time during the logging cycle, you can view saved readings, or pause logging mode without deleting saved readings.
2. The multimeter continuously records intermittent faults
Some multimeters not only have min/max/average logging, but also combine this feature with another feature called AutoHOLD and larger memory to form EventLogging meritorious.
The automatic hold power can sense when the measurement signal becomes unstable and when it becomes stable again. Using auto-hold to trigger the start and stop of the min/max recording function allows the DMM to go beyond detecting faults that produce min or max values.
If the multimeter has an infrared RS232 interface, the continuous recording power will be more powerful, and it can become a simple event collector to transmit the data collected by its multimeter to the computer.
Using a computer, a detailed analysis of each stable and unstable event can be performed. From: Home of Electrotechnical Technology
Not only can you view the minimum and maximum values within each stable and unstable cycle, but you can also view the start and end times of each cycle. The average value for each cycle is also recorded. At the same time, the change trend graph of voltage or current can be dynamically detected.
3. The multimeter marks the recording time
The time at which the minimum and maximum values are detected is useful information for determining the cause of intermittent failures. The DMM in Min/Max/Average logging mode can store the amount of time between when it starts logging and when a new minimum, maximum or average value is saved. Therefore, each saved minimum, maximum and average value has a "time stamp" corresponding to it.
Now, digital multimeters with digital acquisition or storage, through the computer or their own memory, also have the same strip recording function.
If the DMM has a min/max/average recording mode, the DMM will read the input readings at regular intervals, just like a tape recorder.
But unlike a tape recorder, which saves a reading, the reading is compared to a previously saved reading to determine if the value is higher than the previous maximum or lower than the previous minimum. If so, it will be replaced with the new reading. The value originally held in the high or low reading register.
After a period of recording, you can recall these registered values for display and view the maximum and minimum values during the recording time.
You can easily calculate the actual time when the DMM detects the reading by simply recording the time when the min/max/average logging modes are activated separately.
For example, assuming you activated recording mode at 3:07:00 PM and the time stamp of the maximum reading displayed was 47:05, a simple addition of the time stamp and the start time would determine the time when the maximum reading was recorded .
Utilizing the DMM's Min/Max/Average recording mode is very effective for diagnosing intermittent faults.
However, it assumes that the connected circuit points at the time of the fault are sufficient to exhibit either a maximum or minimum value. If the reading caused by the fault is between the maximum and minimum values, then the min/max/average function would not be very helpful in determining the cause of intermittent failures.
During Min/Max/Average recording mode measurements, do not disconnect the test leads from the circuit under test until the HOLD button is pressed to stop recording, or until all saved values have been viewed and archived.
Disconnecting a test lead while recording will cause the multimeter to process the value that appears on the disconnected test lead and affect the average value saved while the test lead is connected, and can affect the minimum or maximum value saved.
