Posted to News on 20th Oct 2008, 15:06
Lenze 8400 HighLine inverters incorporate motion control
Achieving positioning in motor drive systems used to require a separate motion controller. More recently, servo drives have offered integrated positioning, which saves on purchase cost, installation time and panel space. Now Lenze is launching an inverter that has an integrated positioner as standard. Although some applications still need the precision and speed of servo technology, the majority of positioning demands can be achieved with a powerful inverter in combination with an asynchronous motor. Therefore, this new development is claimed to offer machine builders a step reduction in cost from servo to inverter technology.
The new 8400 HighLine frequency inverters, part of the Lenze L-force portfolio, feature point-to-point positioning as standard for up to 16 position destinations. The 8400 HighLine offers all the cost savings expected from combining two drive elements - the motion controller and the frequency inverter - into one. Purchase cost is reduced, and the machine is faster to build with less cabling and a smaller panel size. In addition, performance pushes into the area previously thought of as requiring servo technology, with positioning accuracies possible of 0.1-0.2mm at 60 operations (120 movements) per second. The HighLine also offers advanced features such as linear and S-shaped travel profiles, a touch probe function, homing selectable from 14 modes. and teaching of positions.
Open- or closed-loop control
Both open- and closed-loop positioning are possible but a two-track encoder is needed for a higher level of precision. The signal is evaluated in the inverter at up to 100kHz and, with a suitable mechanical configuration, can lead to an accuracy of 0.1mm. This is aided by a selectable servo control mode, effectively giving enhanced closed-loop vector operation.
Setting up the inverter drive in a positioning system is easy. Lenze's L-force engineer software accepts normal physical values, for example 'millimetres,' and is intuitive. There are many types of machinery needing positioning without the high performance and expense of servo drives. Examples are cut-to-length machinery, goods hoists, positioning conveyors, turntables, gates and dosing pumps. Where linear speeds are high, Lenze recommends toothed belts, which provide low backlash and low inertia. Where machines need a higher stiffness, typically where short travel paths and higher levels of accuracy are needed, ball screws are recommended.
A range of 8400 HighLine inverters is available for powers 0.25-15kW and will soon be extended to higher powers. As well as the positioning functionality, there are other features such as the ability to deliver 200 per cent rated torque, an integrated brake chopper, switching logic for spring-applied brakes, and a plug-in memory module. CANopen communications are standard and optional plug-in module for other fieldbuses such as Profibus can be added. These inverters can be supplied with a Safe Torque Off (STO) module that complies with IEC 61508 (and EN/IEC 62061) SIL3.
Follow the link for more information about Lenze 8400 HighLine inverters.
