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3.1 “No Touch” sensor system
Type: Alfa Laval “No Touch” System
For wire connections: See section 4.5 “Electrical connection, internal”.
Features
• Easy and simple set-up, using locally pushbuttons
• No manual sensor adjustments at all
• No sensor “movements” due to vibrations
• Modular and hygienic design with exchangeabilities
• Clear LED’s for visual status indication
• Set-up parameters saved in case of power failure
Sensor system
Unique “No Touch” sensor system without any mechanical sensor adjustments. A magnet is mounted on the valve stem and
the magnetic field (axial) is detected by sensor chips inside the sensor unit. The measuring angle from each chip is used to
locate the current position of the valve stem with an accuracy of ± 0.1mm. Note that the distance to the magnet can be 5
mm ± 3 mm.
Feedback signals
The sensor system can be used for 2 digital PNP/NPN feedback signals. Selection of PNP or NPN is done by a jumper.
Two of the feedback signals can be used for external sensors if necessary.
Output signals from the sensor unit to the connected digital interface (PLC).
Nominal voltage: Same as connected to the ThinkTop® Basic.
Load current: 50 mA typical, 100 mA max.
Voltage drop: Typical 3 V 50 mA.
Power supply - DC:
The ThinkTop® Basic is designed to be part of the PLC’s Input/Output (I/O) system. It should be supplied from the same
protected power supply as the other I/O devises. The I/O power supply should not be used for other kinds of loads.
The unit is reverse polarity and short circuit protected. The power supply must meet the requirements of EN 61131-2.
Supply voltage: 10 - 30 VDC.
Supply voltage nominal: 24 VDC (+20%, -15%) - pr. EN 61131-2.
Max ripple: 5% of nominal supply voltage.
Supply voltage absolute max.: 30 VDC.
Supply voltage absolute min.: 10 VDC.
Supply current*): Max. 45 mA (for sensor unit alone, excluding solenoids)
*) The initial current during power-on is higher. The actual shape of the current pulse depends on the power supply used.
Typical values are 150 mA RMS during 13 ms (regulated PS) to 330 mA RMS during 8 ms (unregulated PS).
3. Technical specifications3.1 ThinkTop® Basic, PLC 10-30 VDC interface
PLC,
DC feedback