Henkel LOCKTITE 97211 Benutzerhandbuch

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2    Description 
   
At the Preamplifier Online Monitor 97211 the amplification factor has to be adjusted to 
get an optimum signal for correct interpretation at the Loctite controller. Before each new 
start of a dispensing cycle, the controller generates a ready signal or fault signal. This 
happens at the end of each dispensing cycle. 
   
In case of failure of the sensor, no measuring signal corresponding to the reference 
measurement can be generated. For this reason, whenever a failure occurs, the system 
will always generate a fault signal at the end of the dispensing cycle. Therefore the 
complete system is fail-safe if linked to a Loctite controller, i.e. even in case of partial or 
complete failure no dispensing cycle will pass unchecked. 
   
The type sensors used in the system are absolute pressure sensors. Variations in 
atmospheric pressure such as they may result from weather conditions will affect 
measurements in a slight but negligible degree. Temperature fluctuations have an effect 
on viscosity and consequently on product dispensing where pressure reservoir/valve 
systems are used. 
   
The integrated flow monitor of the Loctite controller recognizes the consequences of 
these influencing factors, such as changes in the quantity of material dispensed. 
To achieve absolutely constant dispensing results would actually require adapting the 
dispense pressure to the temperature and thus to the viscosity. In the field, these 
variations in quantity due to temperature fluctuations can mostly be tolerated. 
   
However, if the dispensing result deviates too much from the desired bead configuration 
due to major temperature variations, the displayed error rate will increase, and the 
dispensing pressure will have to be adapted by authorized personnel. In this case a new 
reference measurement has to be made. 
Therefore, a seasonal check and, if required, adaptation of settings may be advisable. 
 
 
In summary it should be noted that a new system reference measurement is only 
required, if error rates are too high to be accepted and after dispensing has been 
checked and readjusted by authorized personnel. The fail-safe design ensures that no 
inspection of the system at regular intervals has to be done. 
Interpretation specifications: 
–  The sample rate is 1 kHz, (1000 measuring points per second). 
–  The minimum and maximum time of measurement are 0,03 and 15 seconds.