Description Of The Centrifuge; Operating Panel (A2); Electronics U320 Resp. U320R (A1) - Hettich UNIVERSAL 320 R Repair Instructions

3

Description of the centrifuge

These microprocessor controlled centrifuges mainly consist of the following electrical
components:

• Operating panel (A2)

• Electronics U320 (A1) resp. Electronics U320R (A1)
• Motor with 2 speed sensors (B2.1, B4) and imbalance sensor (B2.2)
• Brake resistor (R1)
• Motor-driven lid lock (A3)
• Cooling system
3.1 Operating panel (A2)
The buttons, the LCD display, the status LEDs and the acoustic beeper are located on
the operating panel.
The operating panel is connected with the Electronics U320 (A1) via a 16-pole flat
ribbon cable.
3.2

Electronics U320 resp. U320R (A1)

There are 2 microprocessors on the Electronics U320 . Both processors (control- and
drive-processor) are communicating internal via a serial interface.
The control-processor carries out the following tasks:
• Reading in the buttons and controlling the LCD display and the LEDs.
• Saving of 9 run programs.
• Evaluating the errors recognized by the frequency converter.
• Voltage supply and evaluation of both speed sensors (tacho).
• Voltage supply and evaluation of the imbalance sensor.
• Controlling the motor-driven lid lock.
• Voltage supply 15 V DC and 5 V DC for the operating panel.
• Evaluating the temperature sensors and controlling the cooling.
• Evaluating the overtemperature switch in the centrifuge chamber.
• Status indication with an orange respectively a red LED:
All functions are all right:
Case of error:
Control-processor does not clock:
The frequency converter carries out the following tasks:
• Generating the motor current supply
(three-phase current with variable frequency and voltage)
Functional description: The supply voltage is rectified, smoothened and
• Monitoring the motor current.
• Evaluating the overtemperature switch in the motor.
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the yellow LED lights up
the yellow LED flashes
the yellow LED does not light up
chopped into a pulse width pattern in three bridge
elements with a microprocessor.