Electronic digital calipers seldom have problems. The few problems which
customers may encounter usually result from wearing out of batteries, or
from poor battery contact or from the breakdowns as follows:
1) Fixed digits ---- resulting from accidental trouble in circuit,
accompanied by display of some irrelevant signs or symbols.
Solution: Take out the battery and put it back after waiting at least 30
seconds. It should become normal after several trials.
2) Flashing digits ---- resulting from low electric voltage. To get it
solved, you need to replace the battery as soon as possible.
3) Figures displayed in disorderly manner ----- resulting from its unstable
display. It results from the wet protective sticker. To get it solved,
please refer to the above-mentioned operating instructions.
4) No display ---- resulting from no electric voltage.
Solution: Take out the battery and examine the condition of the battery
contacts. If they appear dirty or corroded then clean the battery contacts
until they are visibly clean. Put battery back. Display should visible again.
5) Mechanical abrasion:
The method of repair is about the same as that of a vernier caliper's. But
be careful to avoid any forceful striking, straightening or bending. The
striking, straightening or bending should done after the electronic parts
been taken apart. Repair can also be done for more times than before
not only because 'Zero' can be set at any position but also because it's
not limited by zero - error of vernier calipers.
1) Before using, clean the surface of the protective sticker (the label
over which the readout head travels) of digital measuring instruments for
several times with dry, clean cloth to remove water or other substances
which might congeal or otherwise interfere with the smooth and dry travel
of the readout head.
Because water is a weak electrolyte, the ionization of pH indicator and
hydroxyl ions can be made. These ions will weaken or destroy capacitive
signals to such extent that display will be in a state of disorder.
Attention should be given to it in wet conditions. At present, waterproof
digital calipers been put on the market, but are much higher in price.
2) Working Environment: Temperature: 5-40 °C; Relative humidity:
below 80%. Under such environment, it can prevent liquid containing
electrolyte from wetting the protective sticker.
3) Never apply any electric voltage onto the frame of a digital caliper; or
by scribing on it with an electroprobe. Its circuitry may be destroyed.
4) Zero Adjusting:
Clean measuring faces (by rubbing a clean piece of paper between measuring
faces for several times) and connect one measuring face with another. Exert
pressure of about 3-5N onto the closed measuring faces. The measurement can
be reset to zero by pressing Zero-setting Button. The pushing force exerted
in zero-adjusting should be equivalent as far as possible to the one
exerted at time of measurement in order to reduce measuring error.
5) Measuring Instruction:
Usually, Absolute measurement is taken. 'Zero' is set as mentioned above.
Difference measuring is usually taken to improve the accuracy in
measurement. First, place a block gage (about a size of a measured item) or
place other work piece of standard size) between measuring faces with proper
pressure (3-5N) and then set relative the zero position with the Zero
button. The difference of standard size is displayed at time of the
measuring of an item (Because the difference of value is small, it's
usually called difference measuring). The sum of difference and the above-
mentioned standard size is the actual size of the measured item or the
6) Data Output and Processing
At present, most digital calipers from China have a data port (SPC) for
data output. The port can be seen by removing a small cap on the slider
(readout head) and can be connected with a PC or a printer for data
processing or for the printing of analytical charts of the measured
figures; via a special cable. The data port is usually termed an adaptor.
Interface working method: Synchronous serial.
Data: Binary code, 24 bits. Each datum will be transferred twice. The cycle
is 300ms (20ms in fast reading state). Transmitting time: 0.5ms.
Four wires (from left to right): Negative power(-), Clock pulse CP, Data D,
Pulse range of data: Level ≤0.2V, Level ≥1.3V
Clock Pulse CP: 90 KHz, effective for high electrical level.
7) Replacement of battery
Abnormal display (digits flashing or even no display) indicates a dead
battery. The 1.55V silver oxide button cell should be replaced (battery
#SR44 which is widely available: as it fits many other electronic devices).