Special Calibration Labels

Two SPECIAL CALIBRATION labels are shown in view C of figure 1-1 that have black lettering and a yellow background; the size and content of the labels are different. A SPECIAL CALIBRATION tag (figure 1-1) is used with the smaller of the two labels. These labels or tag are used when some unusual or special condition in the calibration should be drawn to your attention.

Such special conditions may be deviations from usual calibration tolerances, multiple calibration intervals, or a requirement for in-place calibration. The special condition that resulted in the SPECIAL CALIBRATION label should be described on the large label when sufficient space is available on the instrument or on the tag when the small label is used. Brief descriptions of special conditions are provided in the following paragraphs.

Q.6 An instrument that must be calibrated in place requires what type of calibration label?

In cases where you do not require full instrument capability, the calibration can be performed with reduced tolerances or cover less than all ranges and parameters. This approach is often used when the instrument does not meet full calibration tolerances on certain ranges or parameters, but can still meet user requirements. On the other hand, the special calibration may be for higher accuracy than usual on a short-term basis upon your specific request.

MULTIPLE CALIBRATION INTERVALS. - Some instruments have components that require calibration less frequently than the rest of the instrument. For example, the attenuator in a signal generator may require calibration every 12 months, whereas the rest of the instrument parameters should be calibrated every 4 months. Since the attenuator calibration is time consuming and may require unavailable standards, use of the multiple-interval approach can save considerable time (man-hours) as well as permit the more frequent calibration to be performed at a lower level laboratory.

When a specific instrument has been designed for multiple calibration intervals, such information is provided in the applicable calibration procedure. The SPECIAL CALIBRATION label or tag is annotated with the words MULTIPLE INTERVAL, and the type of calibration performed is indicated; for example, partial 1 of 2, 2 of 2, complete calibration, and so forth. The calibration due date reflects the due date of the next partial or complete calibration.

CALIBRATION IN-PLACE. - Some instruments should be calibrated in-place. Annotation on the SPECIAL CALIBRATION label or tag will alert both you and the calibrator that the instrument should not be removed, but should be calibrated in-place.

User Calibration Label

Some test and measuring equipment (T&ME) should be calibrated by you instead of your referring the instrument to a calibration facility. For example, some instruments, such as hardness testers and densitometers, are provided with their own standards and should be calibrated each time used, or at least very frequently. Some instruments, such as oscillographic recorders, may require calibration before, during, and after each use.

Other automatic test equipment (ATE) have self-calibration tests that should be performed each time used or each day of use. Still other instruments are calibrated as part of checkout procedures performed daily or weekly and recorded in maintenance logs. Whenever recognized, the requirement for calibration by the user and the calibration interval (each use - daily, weekly, every 100 hours - each overhaul, and so forth) is indicated in the Metrology Requirements List (METRL).

The USER CALIBRATION label, shown in view D of figure 1-1 , has black lettering and a white background and is affixed when the calibration is performed by the user; however, this label is not replaced at each calibration. When the label is first attached to the instrument, it is annotated as to the appropriate calibration interval. Records of calibrations performed, when other than each time used, should be by normal maintenance practices; that is, in the maintenance log, on maintenance action forms, and so forth.

Inactive - Calibrate Before Use Label

In the event that an individual instrument due for recalibration will not be used for some time in the future, you may indefinitely postpone the recalibration by affixing an inactive label to the instrument. As shown in view E of figure 1-1, the INACTIVE - CALIBRATE BEFORE USE label has green lettering and a white background. The INACTIVE label remains on the instrument until it is recalibrated. The instrument is not to be used while bearing this label.

Calibration Not Required Label

Test equipment standards and T&ME not requiring calibration are shown as CALIBRATION NOT REQUIRED. This label, shown in view F of figure 1-1, has orange letters and a white background. It is attached to and should remain on the instrument indefinitely unless its calibration requirements change. If the instrument is not listed in METRL, you should use the following criteria when placing instruments in the CALIBRATION NOT REQUIRED category:

Instrument does not make quantitative measurements nor provide quantified outputs. The device is "fail-safe"; that is, operation beyond specified tolerances will be apparent to the user. All measurement/stimulus circuits are monitored during use by calibrated instruments or are dependent on external known or calibrated sources for performance within required limits. (When determining that an instrument falls into the CALIBRATION NOT REQUIRED category, you should annotate the label as to the authority for the decision, such as METRL, technical manual, letter or message from higher authority.)

Rejected - refer To Attached Tag Label

In the event that an instrument fails to meet the acceptance criteria during calibration and cannot be adequately repaired, a REJECTED - REFER TO ATTACHED TAG label is placed on the instrument and all other servicing labels removed. This label, as shown in view G of figure 1-1, has black letters and a red background. In addition to the REJECTED label, a REJECTED tag, giving the reason for rejection and other information as required, is attached to the instrument. Both the label and tag remain on the instrument until it is repaired and recalibrated. The instrument is not to be used while bearing a REJECTED label.

Calibration Void If Seal Broken Label

The CALIBRATION VOID IF SEAL BROKEN label, shown in view H of figure 1-1, has black letters and a white background. It is placed over readily accessible (usually exterior) adjustments to prevent tampering by the user when such tampering could affect the calibration. The label should not be used to cover adjustments or controls that are part of the normal use and operation of the instrument. This label may also be used to prevent removal and/or interchange of plug-ins, modules, subassemblies, and so forth, when such removal or interchange would affect the calibration.

REPAIR PROCEDURES

If you are unable to replace a known failed component with onboard spares, you can often locate the replacement component from other supply sources. The replacement component can then be delivered, along with the inoperative equipment, to the IMA. So by sending the repair part along with the equipment, you can reduce repair time considerably. This is particularly true when your unit is getting under way and no time is available for you to complete the repair before calibration. Most operational commands have a higher supply priority for purchase of repair parts than the IMA can use.

"No Reject" Policy

IMAs have a "no reject" policy on test equipment to provide operational test equipment in a more timely manner. The "no reject" policy says, in effect, that test equipment submitted to the IMA for calibration, which is later found to require repair, will be repaired by the repair department of the IMA. Before this policy, any equipment found inoperative by the calibration lab was marked REJECTED, the reasons stated, and the equipment returned uncalibrated to the ship for repairs. The "no reject" policy does not relieve you of your responsibility to ensure your equipment is in working order prior to submitting it for calibration. Its purpose is to streamline the procedure and cut down delays in returning your equipment to you calibrated and ready to use.

Responsibility for Repair and Maintenance of Test Equipment

Generally, the responsibility for repair and maintenance of test equipment is placed on maintenance personnel. In some cases, however, maintenance personnel are not authorized to make repairs. Then the test instrument must be sent to a shore repair/calibration facility.

Q.7 Responsibility for repair and maintenance of test equipment generally rests with what group of personnel?

When test equipment is sent for calibration and repair, all accessories, such as probes, adapters, and calibration sheets, should be included. Only in emergencies or special situations should partial repair or calibration be attempted on test equipment designated as nonrepairable. Such emergency repairs should be noted on a tag attached to the unit and an entry made on the MEASURE card (discussed shortly). The equipment should then be sent at the earliest opportunity to an authorized facility so that permanent repairs can be made and the unit calibrated.

STOWAGE AND HANDLING OF TEST EQUIPMENT

Most electronic test equipment is precision equipment. Such equipment must be handled with care to properly perform its designed functions. Rough handling, excessive heat, moisture, and dust all affect the useful life of the equipment. Bumping or dropping a test instrument may ruin the calibration of a meter, cause short circuits, or damage electronic elements inside the case. Sharp bends, creases, or dents in coaxial test cables can alter the expected attenuating effect and cause false meter readings or measurements. Forced air cooling, dust filters, and heaters are used in many pieces of equipment. This test equipment requires clean air filters for proper ventilation and a warm-up period that permits units in the equipment to maintain calibrated standards.

Electronic test equipment should be stowed in a dry location with the dust cover (if provided) in place. Dust covers for spare plug-in units should be constructed for such stowage. For ease in performing maintenance, the test equipment should be stowed at a location convenient to equipment spaces. If possible, related test equipment should be mounted in the equipment spaces. This reduces the problem of finding adequate stowage space elsewhere.

In stowage spaces, individual pieces of test equipment should be held in place by stretch seat-belt-type straps. If bars are used to hold equipment on shelves, meters and control knobs should be protected by blocking the equipment to prevent it from rolling and sliding on the shelf. Test equipment too large for shelf stowage should be kept in stowage cases and tie-downs provided to secure the cases. Refer to Stowage Guide for Portable Test Equipment, NAVSEA ST000-AB-GYD-010/GPETE, to determine adequate stowage space and proper weight support requirements.

THE METROLOGY AUTOMATED SYSTEM FOR UNIFORM RECALL AND REPORTING (MEASURE)

For the sake of simplicity, we will use the more commonly used acronym MEASURE instead of the full name to describe this system in the next discussion.

MEASURE is a data processing system designed to provide a standardized system for the recall and scheduling of test, measurement, and diagnostic equipment (TMDE) into calibration facilities. It also provides for the documentation of data pertaining to the calibration actions performed by these facilities.

The primary reference document that describes the operation of the MEASURE system is Metrology Automated System for Uniform Recall and Reporting (MEASURE) Users Manual, OP 43P6A. The Chief of Naval Operations oversees this program and establishes policy and guidelines.

Q.8 What Navy office oversees the MEASURE program?