My company, AMPS Industrial Controls, recently finished the installation and start-up on a control system for the Custar Stone Quarry project we mentioned late last year. This quarry is located in northwest Ohio and it supplies stone for road projects all over the region. We are pleased to say that everything went very well and the quarry is now up and running with wireless Ethernet communication between all three control stations.

This was really a fun project so we would like to take this opportunity to explain it in some detail...

Background – Unitronics Vision System With Wireless Ethernet from Westermo

The stone quarry in Custar, Ohio is quite old. It has been crushing stone and providing northwest Ohio with rock for over 100 years! One problem, though, is that the numerous expansions and upgrades which have happened over the decades have resulted in control stations positioned all over the place. Our job was to integrate all the conveyors and crushers into one central PLC-based control system that could be operated from any location in the quarry. Ideally, this would be done wirelessly so as to simplify installation.

Of course, reliability was a great concern. This quarry runs year-round and downtime is very costly. We must ensure that any breakdown in wireless communication would not result in shutting down the quarry. Safety was also a big concern. Great care would need to be taken to safely control crushing equipment remotely. AMPS Industrial Controls would also build the electrical control panels which must hold up to harsh outdoor conditions and be very reliable.

We decided a control system based upon the Unitronics Vision line of PLCs would be a good solution. These controllers could be coupled with wireless Ethernet radio modems from Westermo to allow control from anywhere in the quarry. AMPS would handle the programming of the PLCs and would design the system to be reliable, easy to use and intuitive for the operators.

Unitronics V570 to Control Main Operator Station

The 5.7″ color touch-screen on the Unitronics V570 could serve as the HMI for the main control station. The new V1040 may have been an even better product but it had not quite been released when we started the job. This station is located at the highest point in the quarry inside a booth with a window so the operator can see everything that’s going on. It’s a small booth, though, so we didn’t want to take up too much space. The Unitronics V570 was a perfect fit. From this perch, the operator can control all the conveyors and crushers that wind through the quarry.

In the photo below, you can see the main control station circled in red.

Unitronics V350 to Control Other Stations

The other two control stations only really required small HMI screens because the operators are not used as often. Most of the everyday control will take place from the main station. Because the large color touch-screens were not needed here, we selected the V350. Still part of the Vision series of controllers, the V350 provides full Ethernet capability with extensive I/O options but packaged with a smaller color touch-screen.

The photo below shows the small booth where one of the V350 electrical control panels is installed. Not fancy but very nice accommodations in cold weather.

Wireless Ethernet Communication Details

The Westermo RM-240 was perfect for this application. These devices were easy to configure with a web browser. They formed their own WiFi network on site and were very reliable. The antennas were installed at each location and have been very reliable in all weather conditions.

Each Vision PLC from Unitronics was installed with an Ethernet module to connect to the Westermo devices. Modbus IP is the protocol we used.

I can’t speak highly enough of both the Unitronics and Westermo products. This control system has been in use for a couple months now and we haven’t had a single phone call from the customer. It is controlling every conveyor and crusher in the quarry. Even a crusher that draws 4,000 starting Amps! As always, it was nothing but pleasure working with the Unitronics Vision controllers.