Application 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 AS-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 specific 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 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 3 feedback signals + 1 status signal = 4 feedback signals. 2 of the feedback signals can be external sensors if necessary. The status signal is used for detection of the following:
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. Features Tolerance 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. 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, an alert warning will appear in the form of a status signal and a flashing maintenance LED. After 0.5 mm 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 seatlift to be integrated in the top unit. Materials
Technical Data Sensor System:
Electrical connection Direct cable gland entry (hard wired) PG11 (ø4 - ø10 mm). Terminals 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 (AWG 19). Power Supply - DC The power supply to the complete unit is taken from the AS-Interface. The unit is reverse polarity protected.
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 Signals transmitted over the AS-Interface BUS to the AS-Interface master PLC. 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 (Programmable Logic Controller).
Default slave address: 0 IO code: 7 (4 bit bi-directional) ID code: F (slave without profile) ID1 code: F ID2 code: F Slave profile = S-7.F.F No. of nodes: Max. 31 ThinkTops® on a single master/gateway ASi-bus bit assignment For the AS-Interface version, the following bit assignment will be used:
Solenoid valves: Up to 3 solenoid valves in each unit.
**) Filter recommended in tropical regions.
AS-Interface Standard Specification Overview (EN50295) Medium Unshielded two-wire cable for data and energy (30 VDC/typical up to 8A for the bus). Length of bus cable 100 m max. (300 m with repeaters). Number of slaves 31 max. (each slave has its own address). Number of participants Up to 4 sensors and 4 actuators per slave (max. 124, bidirectional = max. 248 binary participants). Addresses Each slave has a unique address. The address is set by the master or by a “handheld” programmer. Messages The master transmits to each single address in turn with immediate response from each slave. Bit-rate 4 bits (net) per slave and message. Cycle time with 31 slaves 5 ms. Error detection Incorrect messages are reliably identified and repeated. Device-interface 4 configurable data ports (as inputs or bidirectional) plus 4 parameter outputs and 2 control outputs (strobe). Process data in the master Cyclic poling of all participants. Master services Initiation of the network. Signal Coding AS-Interface uses a master code in which a negative sin2 pulse represents a falling edge and a positive sin2 pulse represents a rising edge. This neutralizes RFI effects and allows unscreened two-wire cable to carry both power and data reliably. Electrical connection, internal
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Ordering Please state the following when ordering:
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