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5 Measuring
5.2 Adjusting the Preamplifier 97211
The amplification factor has to be adjusted in order to get an optimum signal to noise
ratio for correct interpretation by the Loctite controller.
When you start dispensing a signal is available. The range of the amplified signal is 1-10
V (1-10 LED´s). The minimum signal shall be 1 V (1st LED), then the controller can
interpret it. The perfect adjustment is 4-5 V(4th-5th LED).
• Open housing of the Preamplifier.
At the controller:
• Press button until the product flows
out of the dispensing needle.
During the dispensing some LED´s lights
up at the Preamplifier.
• Turn the potentiometer R10 till the first
4-5 LED´s lights up.
• In order to control the correct function,
start a new dispensing cycle.
At the beginning of the dispensing more than these 4-5 LED´s light. This shows you the
correct function of the sensor. During dispensing only the adjusted LED´s should light.
The amplification factor is perfectly adjusted.
If you do not reach any indication it shows you, that the usable signal is too low or the
sensor is damaged. Before you change the sensor, try one or a combination of the
following steps to reach a usable signal.
– Change the size of the dispensing nozzle to a smaller one.
– Increase the dispensing pressure
– If a dispensing valve with suck back is used, decrease the suck back of the
dispensing valve (see operating manual of the used dispensing valve).
After this it could be necessary to increase or decrease the dispensing time to reach the
required dispensing quantity.
If you get no result see Section 7.