Housby may have fulfilled its promise to design and build the best mixer with today's technology with the development of the Ready-Link system. The concept of control of the mixer's operation by a computer program linked to the plant batch controller is one quality control engineers will come to love. And if the programmable logic controller (PLC) is as powerful as it appears to be, this portable mixing computer may revolutionize concrete production and quality control.
The fleet manager may view the controller in its present form as yet another tool in the preventative maintenance toolbox. The PLC can track total drum rotations, information that can be used to predict a mixer's service life. By monitoring the hydraulic operating pressure and noting unexpected spikes or drops, the PLC can alert a mechanic of a misaligned or flat drum roller. It can even detect, via resistance to the drum's rotation, if the driver is properly maintaining drum fin cleanliness. The controller can be programmed to detect some of the most common driver mistakes, such as driving with the chute still extended downward.
The system's greatest potential is in quality control. Here are some potential quality control functions Tom Holtz, Housby marketing manager Holtz predicts for the use of the electronic controller.
- Air content control. Preset revolution routines may go a long way toward reducing high air readings at the jobsite by helping to eliminate over-mixing.
- Slump control. By linking its controls to the slump meter, the PLC could sense when the mix is either too wet or too dry.
- Water-cement-ratio maintenance. The PLC could not only limit the amount of water that could be added, it could also ensure that the proper drum rotation routine is used in the retempering operation.
While some of these quality control functions are still in development for Housby's PLC, Holtz notes strong producer interest in this type of technology. "It's the wave of the future. We're working on creating data links through wireless communications that tie these computers to the plant's dispatching and production software," says Holtz.