Eurotherm of Leesburg, Va., a unit of Invensys plc, has introduced the EZ Pro motion controller for injection molding and blow molding.
The unit can reduce motion times up to 20 percent. That big decrease in time is the result of mixing open- and closed-loop control. During acceleration, the position and speed of the axis are monitored to assure that the position does not get ahead of the position target and the speed does not exceed the target velocity. If either of these conditions happen during the acceleration phase of motion, the axis enters closed-loop position control. When there is no overspeed in acceleration, after the acceleration is complete, the output will be held open loop for a period of time before moving to closed loop for the cruise or constant speed portion of the motion.
In extrusion, Eurotherm introduced a machine interface designed to be used with its plastics controllers, the Extrusion Master and MACO, as well as other processing equipment. One benefit is separation between the monitor and the computer. This allows the more shock-sensitive computer to be mounted in the main electrical panel instead of on a swing-away arm or on a stand in front of the machine. Separating the monitor from the computer also allows machinery builders to offer several monitor sizes while only supporting a single computer.
Eurotherm said it has incorporated advanced drive control into its Extrusion Master controller. Normally, complex extrusion lines are started up with the gear pump drive in closed-loop pressure control and the extruder drive running open loop. The melt pump in start-up mode is typically in a direct-acting loop. Once the line nears the desired speed, the user typically wants the melt pump drive to go into open loop and the extruder drive to go into a closed loop. But this complex operation requires a gradual ``ramp-up.''
Extrusion Master reduces the start-up and shutdown processes. The operator simply enters the desired speed and pressure, and the system automatically performs this process.
A new temperature controller, model 3216, has text display and high-accuracy input. It stores five recipes with 48 parameters per recipe. It also features an easy-to-use text display.
The model 3508 and 3504 controllers are designed for demanding, accurate single-loop control applications. The scrolling text display shows the exact name of parameters and alarms saving time during operation.
Eurotherm also introduced the Optima Touch control panel, which combines the flexibility of an industrial computer and the reliability of a dedicated operator interface. Flexibility comes from an embedded Windows XP operating system. The Optima Touch can be mounted on extruders, injection molding machines and blow molding machines.
The low-cost Maco SRS (small rack system) for injection molding uses general-purpose programmable logic controllers, but it also offers advantages of integrated, total control in a compact package.
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