• To replace unreliable & unserviceable motion-control unit

The Danfoss motion control unit had been fitted onto the machine when it was built over in the States. Subsequently, the company who had initially installed the unit was unable to offer any further assistance. Therefore, any problems with the motion control unit would effectively render the machine useless.

The customer decided the best option would be to allow Robtec to design and install a new PC based motion controller. Thereby, not only obtaining greater reliability, but also ensuring a decent level of service and back-up in the future.

Note: Shortly after receiving the purchase-order to go ahead with the work, Robtec was informed that the original motion control unit had developed a problem. The customer was therefore keen to reduce the quoted 12 week delivery time quoted. By reorganising work-loads Robtec was able to develop and install the new control system within 3 weeks.

The machine is a simple single axis unit requiring a PTP (Point-to-Point) motion controller. The original Danfoss I/O module can be seen in the picture to the left. The drives are situated on the other side of the panel, and the ultrasonic frequency generator can be seen to the top right.

Complexity arose from the fact that the previous system had a bespoke PC front-end. This allowed the operator to select from a database of stored component parameters to be used in the machine part-programme.

It was decided that the best option for the customer would be to install a Beckhoff PC based PTP motion control, with a Robtec designed Visual Basic front end.

The writing of the PLC software for the motion controller, plus the Visual Basic software for the front end took 2 weeks.

As the Visual Basic front end was written in-house, then it could be configured to be almost identical to the front-end on the previous system. The machine operators would therefore only require minimum training on the new system.

The Beckhoff I/O modules were installed and wired in over a period of two days, and the new PC slotted into the same position where the previous Danfoss front-end unit was situated.

This can be seen in the lower photograph.