Manual Tablet Testing Instrument 3-in-1 - Type PTB 311E
29-02860_09.1.0E Page 2 of 5
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by the contact speed and force increase rate. Faster
operated test jaw means lower reproducibility and often
higher results. In order to offer the possibility to select an
operating mode which will offer you similar results as the
instruments you may already use, we allow to select the force
mode, linear force increase or linear speed increase as we
do for the rate. The only parameter we do not alter is the
force touching the sample which is for all Pharma Test
Hardness Test Instruments very low as if you would try to
break by hand. When touched we start to increase.
Which force mode to select ?
Since more than 10 years all PHARMA TEST Hardness Test instruments offer the possibility
to select either linear Force or Speed increase.
Linear force increase certainly offers the most accurate control, as the rate of increase is
directly controlled by the electronically load cell used to read the force. Also it is quite simple
to validate the correct and linear operation as a Tablet of 100 Newton hardness will be
broken within 5 seconds if 20N/s had been set.
Linear speed increase can also be used. Here the driving speed of the stepper motor is kept
linear. Actually if the touching force is kept low there is not too much difference in results
between the 2 systems.
Calibration and Validation
Built-in calibration and validation program for all 3
stations. For thickness and diameter certified reference
blocks, 1-20 mm, are used for both validation and
calibration. To validate the hardness test station the PT-
MT magnetic tablet or different certified weights are used.
Use the PT-MT to qualify the correct breakpoint detection,
select a force, for example 50, 85 or 130 N and run a test
series, the resolution of the results should be within 1.0N.
The PT-MT instrument works like a tablet, it withstands
force and than “breaks”. For the 2 point calibration of the
hardness station a certified reference weight of 10 kg is used. All calibration and validation
results can be printed and countersigned. The PT-MT3 will be used to qualify both,
breakpoint detection as well as correctness of the set force increase rate.
To prove the linearity of the instrument, the operator can program a print-out of the force
curve recorded during a test. This will show the linear increase of the adjusted force mode.
Also different weights, like the PTB-CAL3 which includes 5, 10, and 15kg, may be placed
onto the load cell or the PT-MT3 to validate the linearity. Using the standard RS-232
interface, all results can be transmitted to a computer system.
