Tapes geometry measurement system
[Version 1.0] 08
th
December 2014
4
Operation is based on the so-
called ‘shadow’ principle. The micrometer consists
of two blocks
– transmitter and receiver. Radiation of a semiconductor laser or LED 1 is
collimated by a lens 2. With a tape placed in the collimated beam region, shadow image
formed is scanned with a CCD photo-detector array 3. A processor 4 calculates the posi-
tion (size) of the tape from the position of shadow border (borders).
SCA
N
TAPE
RECEIVER
TRANSMITTER
SHADOW
Figure 1
The principle of thickness measurement is shown in the Fig.2
SC
A
N
TAPE
RECEIVER
TRANSMITTER
SHAFT
SHADOWS EDGES FROM
SHAFT AND TAPE
Figure 2
The tape thickness is calculated as the difference between the position of shad-
ow borders of the tape and the shaft. The position of shadow border of the shaft is con-
trolled by a stand-alone micrometer.
The structure of the control system is shown in the Fig.3.
The system contains a group of 6 optical micrometers 1 for simultaneous control
of the tape width and the group of 9 micrometers, 6 of them are intended for simultane-
ous control of the tape thickness and 3 (subsidiary micrometers)
– to control the shaft
surface position. All micrometers are networked via RS485 interface in the switching
center 3, which also includes the power supply of the entire system. The system con-
tains the controller 4 (PDA) that is designed for data processing, indicating of the meas-
urement results and data storage.
