calibration.pptx

timing circuit and calibration - electronics 2nd quarter

1. What is a timing circuit?

2. What is Calibration?

3. Calibration is the process of comparing the reading of one instrument or equipment with a standard instrument. The reference instrument is already calibrated and referenced to a known set of parameters. The reference instrument should itself be directly traceable to equipment that is calibrated.

4. What are calibration standards? Calibration is the process of matching the standard value of the instrument to the master value (true value) of the instrument. IIM & TE item is taken as standard reference for calibration.

5. What is calibration point? Calibration point is a single source for calibration of wide range of instruments in electronics traceable to NABL (NATIONAL ACCREDITATION BOARD FOR TESTING AND CALIBRATION LABORATORIES).

6. What is calibration error?   If the instrument is not calibrated properly, it will show reading with a higher degree of error. This is called a  calibration error. A  hysteresis  calibration error occurs when the response of the instrument become different to the increasing input compared to the decreasing input. A zero error is where the equipment does not measure correctly at the low end of its measurements closest to zero

7. Factors to consider 1. The age of the equipment 2. Recommendations from the last calibration certificate 3. Changes in the environment 4. Transporting the equipment 5. Manufacturer’s recommendations 6. Maintenance and service history 7. The tendency of the device to wear and produce inaccurate results from use or storage 8. Frequency and severity of use

8. The four basic activities of electronic calibration are: 1. choosing a standard to use, 2. a testing phase, 3. the calibration phase, and 4. the final reporting phase.

9. Choosing a standard to use for calibration The very first step in calibrating a piece of electronic equipment is choosing a standard to use. There are several different standards that exist, from in-house standards created by certified calibration shops to international standards that are applied globally. This can sometimes cause confusion because a calibration engineer does not need to use these international standards for testing, but they do need to have measurements that can be traced back to them .

10. Electrical standards Electrical calibration equipment – used to calibrate instruments measuring voltage, current, and resistance – must be periodically calibrated against higher-tier standards maintained by outside laboratories.

11. Temperature standards Photographs of antique potentiometers used to calibrate thermocouple-sensing temperature instruments

12. The testing phase During the testing phase, a calibration engineer will test the electronics that need calibrating against a test sample. Depending on the equipment that needs calibrating and how it is used, a calibration engineer may choose one of many testing options. Depending on the results exhibited during the testing phase, the calibration phase may or may not need to be carried out.

13. the final reporting phase.

14. Tools for testing and calibrating electronic equipment • Voltmeter, Ammeter and Ohmmeter • Multimeter • Power Supplies • Signal and Pulse Generator • Oscilloscope • Frequency counter • LCR Meter

15. PROCEDURE IN TESTING NEWLY Lesson ASSEMBLED AND CALIBRATED 1 ELECTRONIC TIMER

16. Step 1: Identify the Measuring Devices/Instruments Develop a comprehensive list of every device in your facility that is used to measure something.

17. If the instruments do not have a manufacturer identification number, clearly mark each device with a unique number by attaching an asset number tag, etching the device, or using another labeling method.

18. A numbering system is recommended, especially if any of the following circumstances apply: The device is the standard used to calibrate other devices (such as a NIST-certified) The device is used to monitor a critical control point (CCP). Your facility has more than one of the devices. For example, table scales can be moved easily and the same one may not necessarily be returned to the same location

19. Identify the range of use by specifying the actual time, temperatures, weights, etc. that will be measured by the device. For example, if a floor scale is used to weigh 500 pounds, test the accuracy at 500 pounds rather than at 20 pounds. Also identify the required or accepted range from the certified device (such as +/- 2 pounds, +/-0.50C, etc.)

20. Assign a procedure number for the method of certification, calibration, and accuracy checks used for each device. Documented procedures should include: How to conduct the check.  Acceptable deviations/deviation range.  Corrective action if the results are not within the accepted deviation range.  Documentation requirements

21. The instrument check/calibration procedure should include frequency of the checks for each device, such as daily, weekly, monthly, annually. Also, specify the department or position responsible for checking the devices or for arrangements if an outside agency will be used. Finally, make sure the location of the affiliated results and corrective actions is identified in the procedure.

22. Step 2: Determine Certification, Calibration, and Accuracy Check Requirements

23. Certification of Accuracy. The use of a recognized standard, such as calibration against the National Institute for Standards and Technology (NIST). The use of a NIST- certified device or certified-reference standards is typical for most measuring devices, based on the critical nature of the measuring device accuracy, good laboratory practices, and other standards of the industry.

24. Standardization. Historically, NIST-certified thermometers were glass and mercury, thus, not routinely removed from the lab or brought into production areas. In this situation, a second thermometer was often calibrated against the NIST-certified thermometer. The resulting standardized thermometer was then used for accuracy checks. With today's digital thermometers, most locations are using NIST-certified digital thermometers as their standard for all calibration and accuracy checks.

25. Calibration. Ensure the instrument is capable of handling the calibration standards. Accuracy Checks. Accuracy checks determine if the instrument is reading a true or correct value at a single point

26. Frequency Determination. The frequency of conducting each type of accuracy check depends on multiple factors, including: Regulatory requirements. Manufacturer's recommendations. Industry standards/Good Laboratory Practices. Level of risk to product safety if the device is inaccurate. Inherent reliability. (For example, the least reliable types of thermometers are dial and bi-metal probe thermometers, whereas most digital thermometers are fairly reliable.) Environment of use. Is the measuring device moved (e.g., table-top scale moved during daily sanitation)?

27. Step 3: Methodology Each method of determining the accuracy of a measuring device is to have clearly outlined procedures that an individual can follow with training. A key resource for accuracy checks or calibration procedures is the equipment manufacturer

28. Step 4: Corrective Action Clearly defined corrective action is needed when a device is identified as being out of the accepted range. The obvious first step is to immediately correct the device. If that is not possible, determine if it should be used.

29. Step 5: Verification Verification encompasses at least three activities, including: A scheduled, periodic review of the associated records should be conducted by identified management. Ensure the individual(s) doing the check/calibration are following the procedures and are questioned about what they would do if the device was inaccurate. Ensure the procedures and acceptable deviation range remains valid

30. Step 6: Documentation and Record Keeping A number of documents have been identified, including the procedures for conducting the accuracy check/calibration, the National Institute for Standards and Technology certification, the accuracy check/calibration findings and potential corrective action, and record verification.

31. Steps that will help you establish an Instrument Calibration Procedure _____ Verification _____ Methodology _____ Corrective Action _____Documentation and Record Keeping _____ Identify the Measuring Devices/Instruments _____ Determine Certification, Calibration, and Accuracy Check Requirements