5.5 Electrical Control System
5.5.1 Composition of system
In this Automatic Injection Blow Molding Machine, the electrical control system consisting of world famous brand PLC which is used to charge the operation of the Automatic Injection Blow Molding Machine. The electrical part has complete functions such as various parameter setup, panel operation, display, trouble alarm and temperature control etc. The system includes electrical control unit and electronic control unit.
The electrical control unit includes the temperature control and the motor control; the circuit diagram is shown in Fig.9.1, Fig 9.2 and Fig 9.3. The temperature control unit consists of thermocouple, temperature controller, AC contactor, air switch and heater or heating rod etc. The hot runner is in zone one, the front and middle parts of the barrel is in zone two, and the bottom of hopper is in zone three, these three zones are heated and controled independently(for model WB-6, it is four zones). The overload and short-circuit protection of the current are provided in the circuit, so the alarm indication is available when the circuit of thermocouple or heater(heating rod) is broken. The pump motor is equipped with thermo delay for overload protection.
The electronic control unit consists of PLC, manual operating panel, display operating panel, output power amplifying panel, D/A conversion panel and regulated power supply etc. This circuit diagram is shown in Fig.10.1, Fig.10.2, Fig.10.3, Fig.10.4 and Fig.10.5. |