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ThinkTop® Digital 8-30 or 110 VAC NO/NC

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ThinkTop® Digital 8-30 or 110 VAC NO/NC


The ThinkTop® is designed to ensure optimum valve control in conjunction with Alfa Laval sanitary valves and it is compatible with all major PLC systems (Programmable Logic Controller with 8-30 or 110 VAC NO/NC interface). It is for use in food, dairy and brewery installations and in biopharmaceutical applications.

Working Principle

The ThinkTop® is a control head including indication units and solenoid valves to control all kinds of processing valves. It is used to control and supervise pneumatic valves and it is mounted on top of the valve. It receives signals from a PLC to control the valve and it sends feedback signals to the PLC to indicate when the valve is in a certain position.

To adapt the sensor unit to the specifi c valve and to the application, the user sets up the ThinkTop® either by the local keys or by using the key pad (which is ordered separately). When using the key pad it is not necessary to dismantle the top unit.

Sensor System

Unique “No Touch” sensor system without any mechanical sensor adjustments. A magnet is mounted on the valve stem and the magnetic fi eld (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 (0.0004 inch) Note that the distance to the magnet can be 5 mm (0.2 inch) ± 3 mm (0.12 inch).

Feedback Signals

The sensor system can be used for 4 feedback signals + 1 status signal = 5 NO/NC feedback signals. Selection of NO or NC is done by a jumper. 2 of the feedback signals can be external sensors if necessary.

The status signal is used for detection of the following:

  • - Set-up is in progress
  • - Internal error
  • - Maintenance is required (based on time and/or the self adjustment programme)

The LEDs are constantly indicating the status of the unit: Valve position, solenoid activated, setup and local fault indication, maintenance and seat-lift.

Standard Design

The ThinkTop® has a simple, modular and robust design which ensures a quick and easy assembly/disassembly. It consists of a base containing a sensor unit with LEDs, an activator stem, terminals for internal electrical connection, solenoid valves and a shell. See also Fig. 2 “Basic Design”. It is prepared for upgrading and is exchangeable. The design is hygienic and easy to clean.


Programmes Individual tolerance programmes for all Alfa Laval sanitary valve types are part of the ThinkTop® concept ensuring correct feedback to the PLC for open and closed valve position. If the function is disabled the tolerance band will be ± 5 mm (0.2 inch).

Self Adjustment (SRC/ARC valves only)
The self adjustment feature is an exceptional aspect of the ThinkTop® design. A programme can be activated to allow an adjustment of the tolerance band if the seals in the valve are being compressed or are worn. When the tolerance band of the unit has been adjusted 0.3 mm (0.12 inch), an alert warning will appear in the form of a status signal and a flashing maintenance LED. After 0.5 mm (0.2 inch) adjustment an alarm warning appears: Loss of feedback signal, status signal and steady maintenance light indicating that a replacement of the seal is necessary.

Built-in Maintenance Monitor
The unit can be preset to indicate when the time for maintenance of the valve has been reached. A status signal and flashing maintenance LED can be programmed to return after 3, 6, 9 or 12 months or more.

Other Features
Another very important fact is that the setup is kept until programmed otherwise even during failure in the power supply.

The accurate sensor system enables indication of seat lift to be integrated in the top unit.


Plastic parts: Nylon PA 12.
Steel part Stainless steel AISI 304 and 316.
Seals: Nitrile (NBR). EPDM rubber for SMP-EC activator stem.

Technical Data

Sensor accuracy: ± 0,1 mm (0.0004 inch)
Distance to magnet: 5 ± 3 mm (0.12 ± 0.2 inch
Stroke length: 0.1 - 80 mm (0.004 - 3.15 inch)

Electrical connection
Direct cable gland entry (hard wired) PG11 (ø4 - ø10 mm) (ø0.16 - ø 0.39 inch).

The terminal row of the sensor unit is equipped with screw terminals for both internal as well as external cables and wires. The terminals are suitable for wires up to 0.75 mm2 (AWG19).

Power Supply - AC
The ThinkTop® is designed to be a 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 devices. 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: 8 - 30 or 100 - 126.5 VAC
Supply voltage nominal: 24 or 110 VAC (+15%, -10%) - pr. EN 61131-2
Supply voltage absolute max: 30 or 126.5 VAC
Supply voltage absolute min: 8 or 100 VAC0
Power consumption*): Max. 1.5 VA (8-30 VAC) or max. 2.0 VA (110 VAC) (for sensor unit alone) (Excluding current to the solenoids, external proximity switches and the PLC input current.)

*) The initial current during power-on is higher. Typical values are 440 mARCS during 10 ms (the first half cycle) followed by 270 ms at 2 x normal steady state current.

The fulfilling of the UL requirements in UL508 requires that the unit is supplied by an isolating source complying with the requirements for class 2 power units (UL1310) or class 2 and 3 transformers (UL1585).

Feedback Signals
Output signals from the sensor unit to the connected digital interface (PLC).

Nominal voltage: Must match the selected type of ThinkTop®.
Load current: 50 mA Typical, 100 mA max.
Voltage drop: Typical 3V at 50 mA.

External Sensors
The external sensors are used for seat-lift supervision when seat-lift cannot be internally detected. The sensors get their supply voltage from the terminal row. The output signals from the sensors are connected to two inputs on the terminal row on the internal sensor unit. If the actual setup is set for internal seat-lift, the corresponding external signal is not used, otherwise the external signal logically controls the corresponding feedback to the PLC.

Supply voltage: Must match the selected type of ThinkTop®.
Supply current: Max. 15 mA per sensor.
Type of sensor: 2 wire VAC (EN60947-5-2)
Cable length: Max. 3 m. (16.4 ft.)

NO or NC function is selected with a jumper in terminals 12 and 13. Jumper present = NO. If changing to NC remove the jumper and make a power recycle. A power recycle is always required when changing this function.

Solenoid valves

Up to 3 solenoid valves in each unit.

Air restriction (throttle function) air inlet/outlet.

Manual hold override.

*) Filter recommended in tropical regions.

Type 3/2 or 5/2 valve (only possible with one 5/2 valve).
Air supply 300-900 kPa (3-9 bar) (43.5-.130.5 PSI)
Filtered air, max. particles or dirt 0.01 mm (0.0004 inch).
Max. flow 180 l/min. 47.6 US GPM(
Max. oil content 1.0 ppm.
Max. water content 0.0075 kg/kg air. (0.02 lb/lb)
Throughput° ø2.5 mm.
External air tube connection ø6 mm or 1/4”
Silencer/fi lter *) Connection possible via ø6 mm or 1/4”.
Nominal voltage 24 or 110 V
Nominal power 1.0 W.

Micro environment demand specifications

-4°F to +185°F IEC 68-2-1/2
-40°F to +185°F IEC 68-2-1/2
-13°F to +158°F IEC 68-2-14
  10-55 Hz, 0.7 mm EC 68-2-6
  I55-500 Hz, 10g  
  3 x 30 min, 1 octave/min  
Drop test   IEC 68-2-32
Constant humidity
Cyclic humidity:
+104°F, 21 days, 93% R.H.
+77°F/+131°F 12 cycles
93% R.H.
IEC 68-2-3
IEC 68-2-30
Protection class IP67 IEC 529
Input treshold    
Voltage/current: Type 1 input requirements EN 61131-2
Solenoid signals    
Isolation voltage (1000 + 2 x 117) VAC rms/1min EN 61131-2
EMC Directive 89/336/EEC EN 50081-1, EN 50082-2
UL/CSA Approval    
  8-30 VAC
110 VAC

Electrical connection, internal

  • - Digital interface command signals
  • - Internal connections to solenoid 1-3
  • - Feedback signals to digital interface
  • - Jumper connections **)
  • - Incoming signals from external sensors
  • - Support to external sensors
  • - 6. Solenoid 1
  • - 7. Solenoid 2
  • - 8. Solenoid 3
  • - 9. Supply ~
  • - 10. Supply ~
  • - 11. Solenoid common
  • - Earth
  • - 20. Solenoid common
  • - 21. Solenoid 1
  • - 22.
  • - 23.
  • - 1. Closed valve
  • - 2. Open valve
  • - 3. Seat-lift 1
  • - 4. Seat-lift 2
  • - 5. Status
  • - 12. NO/NC Jumper
  • - 13. NO/NC Jumper
  • - 24. Seat-lift 1*) “upper” ~
  • - 25. Seat-lift 2*) “lower” ~
  • - 26. Supply ~ *) com. ~
  • - 27. Earth

*) Note

  • - Terminals 24, 25, 26 and 27 can be used for external seat-lift sensors as well as for any digital input. Always use an external NO sensor.
  • - Two external signals can be connected, they are associated with feedback signal 3 (seat-lift 1) and 4 (seat-lift 2). External sensor must always be a 8-30 or 110 VAC NO 2 wire sensor. Connect ~ common on terminal 26. The signals from the external sensors are associated as follows: sensor signal on terminal 24 (seat-lift 1) associated with feedback 3 (seat-lift 1), and sensor signal on terminal 25 (seat-lift 2) associated with feedback 4 (seat-lift 2).

**) Note

Jumper present = NO. The selection NO/NC is done by the jumper. If changing the function a power recycle is necessary.

Remember to isolate wires that are not in use.

Examples of connecting power supplies

One power for sensor system and solenoid valves:

Two power supplies, one for sensor system and one for the solenoid valves:

Example of connecting power supplies

One power supply for sensor system and solenoid valves:

Fig. 2. Basic design, ThinkTop®.
  • - Sensor unit
  • - Light guide
  • - O-ring
  • - Base
  • - Adapter
  • - Shell
  • - Terminals
  • - Activator stem
  • - Cable gland
  • - Special X-ring
  • - Air fitting
  • - Solenoid valve (3/2 or 5/2)
  • - Safety valve
  • - Solenoid valve (3/2)

Note!1.) The ThinkTop® for the SMP-EC valve has a longer activator stem which is going through the shell (see Ordering Leaflet).
This is the basic design. The clearance should be approximately:
8.9" x 9.8" (ø225 x 250 mm) (SRC NC, SMP-SC/-BC/- TO, Unique, Koltek MH, SBV, AMP)
8.9" x 12.6" (ø225 x 320 mm) (SRC NO)
8.9" x 11.8 (ø225 x 300 mm) (LKB/LKLA-T)


  • - Solenoids 110 or 24 VAC, 24 VDC.
  • - 5 m (16.4 ft) PVC control cable 12 x 0.5 mm2, (AWG 20).

Cable not UL approved.


  • - IR key
  • - External indication bracket for SMP-SC.
  • - External indication bracket for Unique.

For further information: See also IM70825.

The ThinkTop® has Patented Sensor System, Registered Design and Registered Trademark.


  • - Digital 8-30 or 110 VAC NO/NC.
    Number of solenoids (0-3).
    Type of valve (3/2, 5/2).
  • - Air connection ø6 mm or 1/4”
  • - Please state if for series 700 valves.
  • - For Think Top when used on SRC-LS Stop Valve size 2½" - 4": Special indication pin 9612-6370-01.



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