The Series 1500 wraparound and Series 1600 front-and-back labelers from Labeling Systems Inc. (www.labelingsystems.com) are equipped with a new FX3U PLC from Mitsubishi (www.meau.com) that communicates freely with servos, variable-frequency drives, PLCs, and HMI over a single communications protocol. Better synchronization of all axes of motion is among the chief benefits gained. Less time spent programming is another, as LSI’s Andrew Dondero explains.
"This new PLC has a lot of built-in commands. In the past, we had to write our own command routines, including multiple rungs of ladder code. This is a much more modular approach, which we as machine builders appreciate.
"For the customer who buys and installs such a machine, the advantage is that they can control the entire machine from a single touchscreen interface. In the past, if there were multiple labeling heads, there were multiple operator interfaces, start buttons, potentiometers, and so on. Now at a single interface, the operator can change parameters not only on multiple labeling heads but also on the master conveyor speed, the wrap belt, the top hold down, and the infeed timing screw. All these devices communicate through the FX3U, the master PLC."
Machine operators are better informed, too, when a single HMI provides instant access on how variable frequency drives, servo motors, stepper motors, and PLCs are functioning. Moreover, the operator can easily adjust speed ratios between, for example, the master conveyor and the wrap belt, or between a labeling head and the infeed screw. All these things need to be tightly synchronized. The ability to use a single operator interface instead of relying on an encoder to feed data back to a PLC via a hardwired connection is a significant step forward. Mitsubishi’s Don Edsall puts it this way: "Instead of hardwiring, we have a high-speed serial network among all the drives. It lets the master PLC change multiple speeds on the fly."
On a dual-head LSI labeler, notes Edsall, each labeling head has its own FX1n PLC, also from Mitsubishi. This arrangement, he says, delivers higher speed because the PLCs on the labeling heads take care of the positioning of the labels. All three PLCs have a built-in motion function, says Edsall. Rated speeds delivered by these new LSI labelers is 1800 linear inch/minute.
Integrated servo modules can, potentially, help reduce the time it takes to build a machine, and decrease its installation time and cost.