8. Application Notes and Optional Features
Page 186
DMS 2 Operating Manual
Step 6: When the displayed thickness matches the calibra-
tion standard’s thickness, press
.
Step 7: The TopCOAT calibration procedure is complete.
NOTE:
Thickness calibration procedures are dictated by
probe type and measurement mode. While in TopCOAT
mode, only a one-point calibration may be performed. The
calibration procedure includes probe zeroing.
NOTE:
The calibration procedure determines the velocity
at which sound travels in the specific material being tested.
Calibrations must be performed to ensure reliable measure-
ments.
NOTE:
During probe zeroing and calibration, use only low
viscosity couplant to minimize the couplant thickness
between probe and blocks.
NOTE:
See Section 8.4.4 to properly calibrate for the
accoustical velocity of specific materials.
8.4.3
TopCOAT Probe Zeroing Procedure
The
probe zeroing procedure must be performed each time
the DMS 2 is turned on, and every time you replace a probe.
For best results, the probe zeroing procedure should be
repeated periodically during the measurement session to
compensate for temperature and probe wear. You can zero
often and easily without going through the entire calibration
procedure. Note that the TopCOAT calibration procedure
includes probe zeroing. Therefore, the following procedure is
only required to re-zero an already calibrated probe being used in
TopCOAT mode or when operating in AUTO-V mode.
Step 1: Be sure that you’ve already connected a TopCOAT
(560TC) probe to the DMS 2 and that TGMODE is set to
T-COAT or AUTO-V. Wipe the measurement surface of the
probe so that it’s free of contamination and couplant.
Step 2: Press
. Follow the displayed instructions, apply a
low viscosity couplant, and couple the probe to the zero block
on the front of the instrument.
Step 3: Continuing to follow the on-display instructions, apply
couplant, and couple the probe to the dedicated velocity
reference block.
Step 4: When indicated, probe zeroing is complete.
NOTE:
The probe zeroing block is for zeroing only, and
should not be used as a thickness calibration standard.