The heart of the blow molding system with SIMATIC S7 consists of software blocks, i.e. technology blocks. These are written in programming language C and will run on the M7 (FM 356-4 application module) integrated in the SIMATIC S7.

The performance features of the routines have been derived from the time-proven SIMATIC S5 module IP 252 B and have been extended to enable them to meet present-day requirements.

WTC - Wall thickness control

• Channels for multiple head operation or PWTC operation of continuous or accumulator head machines
• Up to 256 intermediate points for polynomial or linear interpolation
• Automatic cycle time adjustment and display for continuous machines
• Digital mandrel position control
• Ejection speed control with 256-step profile, synchronous with the wall thickness progression
• Tube length control
• Level control
• Quality monitoring: The actual nozzle value (wall thickness) is represented as a profile, parallel to the actual curve. Deviations are implemented.
• Profile position signals
• Valve characteristics

MOT - Combined position and speed control

• 2 (optionally 6) channels, designed to also cope with high-speed movements
• Infinitely adjustable speed profile, e.g. for opening and closing the mold: 16 cams, 23 adjustable speeds
• Position-accurate braking with constant deceleration with respect of time or mean-value deceleration via sin² function
• Constant acceleration over time
• Actuator adjustments via valve characteristics
• Position control
• Speed control
• Monitoring function for manipulated variable and position
• Checkback messages for cam image and zero speed

CAM - Position decoding

• 16-step cam controller, freely assignable

TEMP - Temperature control

• Up to 24 channels can be run on a CPU 614
• Self-setting, separate parameters for heating and cooling
• Encoder monitoring
• Tolerance monitoring
• Short-circuit monitoring

Electric worm drive

The maintenance-free three-phase AC SIMOVERT MASTERDRIVES is of low-noise design and provides fast, accurate worm drive speed control. Compared with a hydraulic drive, the power consumption can be reduced by up to 25 %. Synchronizing of the dosing operation with the machine movements allows the cycle time to be reduced by about 20 %. To obtain more gentle and improved processing of the material, it is even possible to extend the dosing time by reducing the cycle time.

In conjunction with Siemens blow molding machine controls, it is possible with the aid of SIMOVERT MASTERDRIVES to equip fully-electrical machines.