The jaw crushers which operate at rock quarries are designed to break down large materials safely and efficiently into smaller, more manageable sizes. These machines are important to the productivity of a quarry operation and any performance issues can bring operations to a halt.
As quarries are typically located in remote areas, it can be difficult to get service in a timely manner which can cause lengthy delays or quick fixes to be put in place which do not properly address the maintenance issue.
When a problem with crushing equipment occurred at one such site, Fleming Controls and Power Specialties (FCPS) based in Bryant, AR, was called to help get this crucial production equipment running reliably.
Determining Maintenance Needs for Jaw Crusher Automation System
FCPS was approached by quarry personnel to help repair the automation system of a jaw crusher when its controls and associated equipment experienced control system issues that caused operations to halt.
Initially, the quarry operator hardwired a series of relays and switches allowing limited operations to resume in a manual mode while the troubleshooting process was underway. The jaw crusher and associated devices were originally built using a Modicon programmable logic control (PLC)-based system for control and monitoring, but the quarry did not have in-house personnel to support this legacy system. In fact, they did not even have access to the PLC program, which is not uncommon when dealing with original equipment manufacturers (OEMs).
Therefore, running the crusher manually was a stopgap option that severely limited operational throughput. An initial attempt was made for external support to replace the PLC, but this was found to be cost-prohibitive, so manual operation continued. As activity increased at the quarry — requiring the jaw crusher to ramp up production to multiple days per week — the operators knew a better solution was needed.
This is when the quarry approached FCPS to aid in the repair of the jaw crusher’s automation system. As an electrical contractor specializing in industrial design, installation, and repair services, FCPS quickly got to work assessing the client’s needs.
The FCPS and quarry teams quickly determined the best solution would be retrofitting new automation starting from scratch.
Choosing the Right Solution for Performance and Budget Requirements
The first decision for FCPS was selecting the automation platform. The quarry operator valued reliability, but they also needed a cost-effective solution since they did not have ready budget allocated for equipment automation replacement, so the maintenance budget would be stretched thin.
Although FCPS typically uses another major automation brand, the team decided that to meet the budget and delivery constraints for the jaw crusher project they would be better served by using AutomationDirect PLC and human-machine interface (HMI) products (Figure 2).
The selected PLC was a BRX stackable micro brick form factor that does not require a base or backplane. This compact size made it ideal for retrofit within the existing control panel footprint. The BRX line is incredibly versatile, with the functionality, processing power, input/output (I/O) interface, and communication protocols necessary for a modern automated industrial control system.
Additional I/O expansion modules easily snap onto the side of the BRX controller, which was useful for the jaw crusher application. HMI duties would be carried out by two C-more CM5 series color touchscreen units.
Initially, FCPS had some reservations about learning a new platform on a tight deadline, but ultimately, they found it to be an enjoyable challenge. Although there was a lot to learn, there was no shortage of support; the FCPS team was able to leverage tools from AutomationDirect and other industry PLC programming and HMI configuration experience to rapidly increase their comfort level with the BRX and C-more platforms.
The free software provided with both was intuitive and FCPS quickly developed the ladder logic and associated graphics objects.
Automation Technology Selection Eases Integration and Support
As the old controller was removed and the new PLC was installed, it was clear that the existing I/O field wiring was too short to reach. Rather than spend hours replacing it all, ZIPLink pre-wired connection cables and modules were utilized to minimize the need for intermediate connections or splices.
The ZIPLink wiring solution simplified the I/O termination process and reduced the opportunity for wiring errors by extending field connections away from the I/O modules with a connectorized cable and easily accessed field terminals.
While the majority of I/O in the system was discrete, the crusher automation relies on a 4-20 mA input from each of the two crusher motor current transformers (CTs). These signals indicate equipment loading and are used to modulate the material feed rate.
When FCPS encountered a question regarding the integration of these analog inputs, they placed a call to AutomationDirect’s technical support team. In less than an hour, a highly knowledgeable representative returned the call and resolved the issue. This positive experience and swift solution further bolstered FCPS’s confidence in their decision to choose AutomationDirect as the automation supplier for the project.
With user experience in mind, FCPS prioritized simplifying the design so quarry employees could easily operate and maintain the new jaw crusher control system. The user interface follows this principle and features two HMIs.
The primary HMI is a 12 in. unit (Figure 3) with plenty of room to display all of the settings for the crusher controls as well as the status of pumps, motors, and the feeder inputs on a single screen. Alarms can also be viewed and managed from the primary HMI.
READ MORE: Use PLCs for Simple Control of Pneumatic Machines
Due to the large size of the jaw crusher, a second HMI was added as a convenience for localized troubleshooting. The local HMI (Figure 4) utilizes a smaller 10 in. color touchscreen and provides an easy way to manage alarms at the point of work without having to navigate back to the main control panel.
When developing the HMI screens for the jaw crusher, the pre-loaded drag-and-drop icons for pushbuttons and switches, as well as numerous tools and a simulator within the HMI software package, made configuration easy and efficient.
The success realized by FCPS using AutomationDirect products highlights the transformative power of innovative and fit-for-purpose automation solutions. To overcome challenges posed by outdated equipment with prohibitive support costs, the team found the choice of a new retrofit automation and visualization platform emerged as the ideal solution for the rock quarry application.
Robust product performance, unrivaled customer-centric support, and practical value are the types of benefits ensuring companies like FCPS can support their customers in a time of need.
This article was written and contributed by Theodore Thibeau, an automation specialist at Fleming Controls and Power Specialties, Inc.
