How to Calibrate Fluke 87 Digital Multimeter Using Fluke 5522A Calibrator

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As a Technician whether working as a maintenance or in electronics repair field, multimeters is the most used tool to test, diagnose, monitoring, and repair.  Your decisions are based on the data that you have taken or on the output that the multimeter is displaying.

Regardless of the usage, the multimeters should be highly reliable for us  to provide a highly accurate diagnosis or decisions on every testing that we are doing. So the importance of multimeter calibration should not be taken for granted.

In this post, I will present on how a multimeter, specifically the Fluke 87 multimeter is being calibrated using a multi-product calibrator known as Fluke 5522A.

How do we know it is calibrated?

Multimeter with sticker and seal as a evidence of calibration

We can determine if the multimeter that we are using is calibrated by looking or checking if it has a calibration label stick to it. It contains the calibration date and due date of the instrument. (see image).

Furthermore, if it has a label on it, there should also be a calibration certificate  that contains all the details about the instrument plus the calibration results and any limitations that has been observed.

Fluke 87 V Digital Multimeter is one of the best multimeter today. As a simple review,  it has  a higher accuracy, wider frequency range and higher resolution compared to others.

What makes it more usefull is that it has a built in  temperature measurement ( just do not forget to include the thermocouple probe and connector in the set).  Almost all the measuring capabilities are added in one package.

As a calibration technician, utilizing this kind of measuring  device is a good investment and a big help on your troubleshooting environment. But having the knowledge to verify its accuracy is also a big plus because you are not just  making an accurate measurements but also a reliable measurements. You will have a higher confidence on the performance of your multimeter.

How to Calibrate a Digital Multimeter?

Based on Fluke 87 V Specifications, below is a verification/calibration method using a Fluke 5522A Multiproduct calibrator.Verification of multimeters are simple, you just need to have a reference standard  where you can compare your reading and preferebly more accurate than the multimeter (preferably 4:1 accuracy).

Fluke 5522A provides this requirements. The connections are also simple, if you know how to use the mulitmeters during testing, the connections are the same while using the Fluke 5522A calibrator. The only difference is the current connection, usually, current are connected in series with the load, in using Fluke 5522A, it is directly connected in the port of Fluke 5522A, which makes it very simple.

 

 

20160815_114752
Fluke 87 Multimeter Calibration Set up with Fluke 5522A as the reference standard.

Objective:

To define calibration procedures for  Fluke 87-V Digital Multimeter

Calibration Method:

The reading of the Fluke 87 V multimeter is compared by the electrical signal generated from fluke 5522A Multi Product Calibrator. The Multi Product Calibrator can simulate almost all the required signal needed to verify the accuracy of Fluke 87 multimeter. This procedure is applicable almost to all multimeters whether analog or digital.

Requirements:

  • Warm-up time: At least 1 hour for proper stabilization
  • mds
    Sample Measurement Data Sheet (MDS)

    Temperature:   23 +/- 5 deg C

  • Humidity:         50 +/- 10%
  • Perform 3 test points for each range
  • Measurement Data Sheet (MDS)

 

 

 

 

 

 

Reference Standard and Equipment:

 

 

 

 

Procedure:

  1. Allow the temperature of the calibrator and Unit Under Calibration (UUC) to stabilize at room temperature.
  2. Check the battery and fuse , replace if necessary.
  3. Record necessary details on the Measurement Data Sheet (MDS)( Brand, Model, Serial, etc.)
  4. Check for any physical or functional  defect , discontinue calibration  if defects are noted. Inform owner immediately.

     5. Display Test:

5.1. Turn the Unit Under Calibration (UUC) on while holding down the AutoHOLD button to view all segments of the display. Compare the display with the  appropriate example in Figure 1.

Display Test
Figure 1

    6.  AC/DC Voltage Verification:

6.1 Connect the UUC to the 5522A calibrator as shown below.

Fig.2 AC.DC Connection
Figure 2

6.2 Position the rotary switch of the UUC to the desired voltage range function.

6.3  Position knob for AC voltage measurements for all ranges,DC Voltage measurements from 4 V to 1000 V ranges and 400mV range.

6.4 Set the 5522A calibrator to each of the required voltage set-point values shown on Table 1 and take note of the measured values  on the multimeter. Record values on the MDS

    7.  AC/DC Current Verification:

7.1 For current measurements between 4mA and 400mA, make connections shown on Fig. 2. For currents above 400mA, make connections shown on figure 4.

Connection for Current 4-400ma
Figure 3
Connection for Current above 400ma
Figure 4

7.2 Position the rotary switch of the UUC to the desired current range function.

7.3 Press the blue button to select AC or DC mode.

7.4  Set the 5522A calibrator to each of the required current set point values  shown on Table 1 and take note of the measured values on  the multimeter.Record values on the MDS

    8.  Resistance/ Capacitance/ Diode Verification:

8.1 Make the same connections shown on Fig. 2

8.2 Position the rotary switch of the UUT to resistance/ capacitance/ diode range.

8.3 Set the 5522A calibrator to each of the required resistance values shown on Table 1 and take note of the measured values on the multimeter. Record values on the MDS

    9.  Temperature Verification: We will use a thermocouple here.

9.1  Connect the UUC to the 5522A calibrator using a Type-K thermocouple. (VΩ terminal and COM terminal of the UUT to the                            thermocouple port of the 5522A calibrator.)

9.2 Position the rotary switch of the UUC to temperature range.

9.3 Set the 5522A calibrator to the required temperature  settings and take note of the measured values on the multimeter display. Record values on the MDS

    10.  Frequency Verification:

10.1 Connect the VΩ and COM terminals of the UUT to the 3325B calibrator Signal Output using a BNC cable and BNC to dual  banana adapter.

10.2 Position the UUC rotary switch to AC Volts then push the HZ% button for Frequency function.

10.3 Set the 3325B calibrator to each of the required frequency set point values shown on Table 1 and take note of the measured  values on the multimeter. Record values on the MDS

    11. Turn the UUC off, disconnect all cables and secure all connections.

12. If the readings are within the given limits, update the record, do labeling and sealing.

Table 1. Performance Verification Test limits

fluke-87-performance-verification-limits

Click table to enlarge

End of Verification

Multimeter calibration requires a knowledge of basic electronics in order to understand its functions. Calibration is simple if you have this background. Based on the procedure presented, calibrating a multimeter is just like using it, measuring a device (for example a resistor). The only difference is that you know the value to be tested therefore you can verify its accuracy through comparison.

For a list of multimeters please click here.

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Edsponce

2 Responses

  1. Paul Brubaker
    | Reply

    Hi Edwin,
    I need some advice… most of the calibrations and inspections I perform are dimensional, however our business has a dozen multimeters and other relatively low accuracy electronic devices requiring calibration. I am In the market for a multifunction calibrator and have found excellent products from both Fluke and Hewlett-Packard. The only problem is that they both cost more than my house, and can not be justified in our small business. Can you recommend any off-brand multifunction calibrators that only provide more basic functions that don’t cost as much as a Ferrari? Any suggestions would be welcome! Have a great day!

    • edsponce
      | Reply

      Dear Mr. Paul,
      Good Day!
      These are my recommendations:
      a.You can assess if the multimeters have a critical contribution to the quality of your products. If you are only using it as a reference, just say, to detect the presence and value of a voltage or current, but is not necessarily a having a direct effect on the manufactured products, you can label it as calibration -not- required or for reference only. But is should be properly documented. You can check my related post in this link

      b.If it is not that critical in usage and since the multimeters you are using are relatively low accuracy, have one unit/ pc of multimeter calibrated, preferably with the highest accuracy and use it to calibrate other multimeters. You can make a direct comparison every time you use it with the other multimeters. This method is a “limited calibration”, but just in case it is acceptable in your process, you can implement it.

      c.I have found a standard that was introduced to me just within this year, I believe this is far cheaper than Fluke (or a Ferrari ツ)..Please check this model under Yokogawa. 2553A DC Calibrator and 2558A AC voltage current standard. They can be purchased separately.

      Hope this helps,
      Edwin

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