ELAU PacDrive™ Servo drive MC-4

System Overview

Drive Concepts of Packaging Machines

Modern machine concepts in the packaging industry are

characterized by the need for high dynamism, flexibility, modularity

and efficiency. Packaging machines were traditionally equipped

with a mechanical vertical shaft, which drove the secondary

motions in the machine, usually with mechanical components with

complicated motion functions. Designing such a machine, flexible

for different products is a highly complex task.  Even minor changes

in the packaging process, particularly in case of a product change,

require major modifications and standstill time.

Packaging machines with electronic vertical shafts permit full

flexibility. Electronic servo drive systems replace cam and coupling

gears and a virtual electronic vertical shaft ensures that the motion

axes are synchronous. Any pulse and angle synchronous

movements are determined by a central control.

Unplanned machine states, such as stop or emergency off

situations or initialization movements can be realized

synchronously. Dynamic changes of the goods to be packed or the

packaging material in the plant, (like slippage of the products to be

packed or expansion of the packaging material) can be registered

by sensors while the machine is running and eliminated by

modifying the corresponding drive movements. This development

substantially changes and highly simplifies the classical mechanical

machine concept. The structure of the packaging machine can be

broken down into modules that are easy to apply and can be

standardized.

Structure of the PacDrive™ Automation System

The PacDrive™ automation system offers a technically and

economically optimal solution for electronic packaging machines.

PacDrive™ consists of an efficient PC-based control, the PacDrive

Controller and the digital MC-4 servo drive which include the mains

connection unit, the end-stage power and the servo regulator of the

individual axes (Fig. 3-2).

The PacDrive Controller is the intelligent head of the system, and is

based on an industrial PC. The PacDrive Controller synchronizes

and coordinates the motion functions of the packaging machine.

Using an IEC 1131-3 soft PLC, it ventures into applications

previously reserved for standard PLCs. The individual PLC or

positioning tasks can be broken down into several parallel tasks,

which are implemented with the EPAS-4 programming environment

according to the IEC 1131-3 standard. Up to 40 servo axes can be

connected to a PacDrive Controller and supplied with positioning

data.

The circular digital SERCOS real-time bus realizes the safe data

exchange with the servo drive MC-4. Due to the use of optical fiber

technology, the data bus is insensitive to electromagnetic

disturbances and cyclically supplies the decentralized servo drive

MC-4 with new set values at a data rate of 4MBaud. All internal

states of the axes can be checked via the real-time bus and

processed in the PacDrive Controller.

In addition to digital and analog inputs and outputs, the PacDrive

Controller has two serial interfaces and one Ethernet interface. A

variety of process visualization and control systems can be

connected to the PacDrive™ system via the integrated OPC

interface. Further peripheral components can be connected via field

bus interface modules. The PacDrive Controller can act as a field

bus master or slave.

The international field bus standards CANopen, PROFIBUS-DP

and DeviceNet are supported. The built-in interfaces enable remote

diagnosis via telephone modem or Internet. Via TCP/IP, PC’s can

communicate with the PacDrive Controller and diagnose the state

of the control directly.