15
3.8 Dynamic Calibration of the ETB
The tension meter has been calibrated dynamically according to the
SCHMIDT factory procedure.
Therefore, differences may occur between static and dynamic readings.
All tension meters are calibrated with standard materials - such as polyamide monofila-
ment (PA) - according to the SCHMIDT factory procedure. The diameters are given in
Chapter 2.
In 95% of all industrial applications, the SCHMIDT calibration has been proven to provide
the best results and is used for comparative purposes.
Fig. 3.8. shows the basic setup of a dynamic calibration.
The procedure for a static calibration using a simpler setup is described in Chapter 3.9.
fig. 3.8
Line speed Vmax. = ETB 100 m/min
Vmax. = ETPB 60 m/min
Hang twice the weight (pulley effect) which corresponds to the
tension to be measured from the measured material, vertically,
as shown here. Please keep in mind to include the weight of
the lower deflection pulley when you calculate the suspended
weight. Pay attention to the correct unit of measure
cN
.
Requirements for static calibration
:
- The ETB is factory calibrated for a vertical material path (fig. 3.7). Recalibration must
also be carried out with a vertical material path.
- One cN weight each, corresponding to 10%, 40%, 70 % and 100% of the tension range,
must be provided.
- No process material inserted.
- Tension meter switched off.
To select the calibration mode
:
- Press and hold the MEM and
POWER keys until the DISPLAY shows
E 0
cN
.
- Release first the POWER key and then the MEM key.
To calibrate the zero point
:
- Press the RECALL key.
As long as the RECALL key is depressed, the DISPLAY shows a random decimal value
between -2000 and 2000, e.g.
800
cN
.
This decimal value may vary
from instrument to instrument.
If the value is outside this range, calibration cannot be guaranteed.
- Release the RECALL key when the value shown on the DISPLAY is fairly stable
(the reading might fluctuate greatly).
The DISPLAY shows
E 10
cN
.
3.9 Static Calibration of the ETB