A West Coast cement manufacturer contracted Trutegra to replace their forty-year-old production system, which did not incorporate any automation features or controls and did not provide data collection capability. Trutegra designed, constructed, commissioned, and implemented a package that included a PLC, IO, HMI, with motor drive systems, sway and skew control technology, automated positioning via selection with HMI, obstacle avoidance, and automated grab functionality. To do this, Trutegra worked with both the machine builder and the end-user.
Trutegra’s No-Sway technology uses input shaping to modify move profiles so that Load-Swing is essentially eliminated. No-Sway is the ideal solution for cranes when natural load sway is predominant over wind or other outside disturbances.
The system to be replaced was mechanically very stressed and was based on old technology that was difficult to support. The availability of components for the system was very limited, as was the in-house personnel with in-depth knowledge of the old technology. Furthermore, support from service companies was not readily available. Several difficulties were encountered in the implementation of the new system including:
- The harsh environment, which is typical of cement manufacturing,
- Limited access,
- Installation errors,
- Working on the system during production demands.
The lack of qualified project management or electrical experience at the machine builder also proved to be a significant challenge and resulted in more time being spent training personnel than had been anticipated. The machine builder also had issues with the delivery and installation, leading to a delay in the schedule. This delay resulted in the new system being started up by Trutegra while it was being used in production by the end-user, which is not an efficient approach for commissioning.
The old system did not include data collection capabilities, but rather information was being gathered by operators and technicians. The implementation of a PLC, HMIs, and remote connectors in the new system allows evaluation of performance history and identifies recurring or live faults. This capability contributes to the resolution of issues that may prevent the operation of the machines.
Another advantage of the new system was the provision of a display for the operator to observe process conditions and alarms. The absence of this feature in the old system often led to lengthy periods of time being required to resolve issues. The old system was entirely manual, using lever sticks and a seat for the operator that was obviously uncomfortable. The new system contains a large operator cab with filtered air (necessary for the dusty environment in the plant) and a larger AC unit. The HMI displays the position feedback of the crane (using data from the radar units), allowing the operator to determine their location in the building. In the old system, the operator looked down from a glass cab onto the material or looked up at markers on the roof to estimate the location of the radar. This inaccurate approach was replaced by a “GO-TO” feature in the new system, which moves the machine to a selected destination. Also, travel by the machine is limited by this feature, avoiding areas into which the machine should not go, leading to improving efficiency, reducing machine wear, and saving energy.
This new system can readily become fully automatic and is a possible future consideration for the company. A similar project has been completed at the East Coast facility of the company. However, this would require different workers or extensive retraining of the current workforce, since it will demand a different skill set to monitor and maintain a fully automated system. The West Coast plant uses union labor, and the workers believe that automation will cost them their jobs, which represents an issue for the company. However, for the plant to fully automate is advantageous since it allows absolute control of operations in contrast to the operators having free will, which can lead to deviations in the process and result in off quality and/or inconsistent products.
Full automation would require the addition of a SCADA system to the control room to provide remote monitoring and advanced scripting logic, which allows scheduling the movement of the machine based on other process demands within the plant. Currently, the plant communicates with machine operators by radio to provide instructions on what is to be done next. Trutegra has replaced this process at other sites by connecting the PLCs from each system to the machine, using logic rules to determine where to send the product or receive incoming material.