Midget Head - Elcometer Protovale CoverMaster CM52 Operating Instructions Manual

5.12 Midget Head

A midget head is available from Protovale, with dimensions nominally half those of the
standard head.
It is intended to measure covers from 6 to 30mm to an accuracy of typically ±1mm.
The intended application is for measuring covers which are consistently just under 30mm,
without the need to use the white face of the standard head, thereby avoiding the possible
loss of accuracy which can occur in congested situations as described in sections 4.4 and
5.5, which would otherwise have required an additional 10mm spacer. At these shallow
covers, resolution of closely-spaced bars is even better than that achievable with the
standard head.
It may also be used with covers up to about 50mm – but in the 31 to 50mm range, the
error may increase to 2 or even 3mm. For covers greater than about 35mm, the standard
head should be used.
The CM52CoverMaster automatically senses when the midget head has been connected
instead of the standard head. Whenever the midget head is connected, the LCD display
shows a ~ symbol to the left of the digits to indicate this fact.
It is however still necessary to re-zero the instrument (on CALib) whenever the heads are
changed over.
For covers of less than the minimum measurable cover of about 4 or 5mm, the display will
indicate something like :005 or :006 where the leading colon indicates the under-range
situation and should be interpreted as 'less than'.
Please contact Protovale if further information is required.
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