Mobile crusher takes state-of-the-art PLC onboard

A Siemens Automation and Drives product story

Edited by the Engineeringtalk editorial team Feb 27, 2004

A new tracked mobile crusher looks set to raise the benchmark standard for crushing equipment design, combining a crushing force of 60t with unprecedented levels of safety and reliability.

A new tracked mobile crusher looks set to raise the benchmark standard for crushing equipment design, combining a crushing force of 60t with unprecedented levels of safety and reliability.

This performance owes much to an innovative control strategy for the crusher's hydraulics, built around a fourth generation Logo logic control module from Siemens Automation and Drives.

Based in the historic Essex town of Maldon, Taylor Construction Plant is a leading manufacturer of specialist construction equipment, including tracked dumpers, tracked crushers and compaction rollers.

Over the years the company has built an unrivalled reputation for providing its UK and overseas customers with innovative and high quality products.

So when the company embarked on the design of a new mobile crusher, it set itself the challenge of combining impressive specifications with an innovative control system.

In particular, to achieve new performance standards in safety and reliability, the company looked to replace hard-wired changeover relays with a state-of-the-art programmable logic controller.

Taylor Construction Plant's Paul Drew explains: "Mobile plant has to endure some of the most challenging and extreme environmental conditions, all of which place stresses on the control system.

In particular, over time, changes in pressure and temperature can take their toll on the changeover relays, which can affect the repeatability of control of the hydraulic valves.

So we took to decision with the new mobile crusher to replace the relays with a logic control module, and investigated the Logo logic module from Siemens".

The resulting Hi-C40 mobile crusher provides a hydraulic-powered 60t crushing force, with operator safety assured through the implementation of a fully interlocked, four point safety and security system.

The Logo module forms the heart of the control system, sequencing the hydraulics through the crushing cycle and providing centralised control for the safety system.

All the safety interlocks integrate with the Logo to cut power to the machine's hydraulic system in the event of a problem, dumping all hydraulic pressure as well as stopping the engine.

Introduced by Siemens in 1996, the Logo concept has revolutionised the engineering of flexible switching applications, filling the void between discrete switching devices and micro PLCs.

Simple to program and easily expandable, the Logo control module has quickly found favour in new market sectors where programmable control has previously not been considered.

"Not having used logic controllers before, we naturally had some concerns about how long it would take to implement the control system", says Drew.

"But the software was so easy to use that we got a working system up and running in less than a day.

Subsequently we embellished the program, adding new functions that we could never have implemented in hard-wired logic.

As well as eliminating a host of discrete switching products, it also enabled us to implement a much more comprehensive safety system, more easily, and with a lot less cabling".

Taylor Construction Plant is confident that the new Hi-C40 mobile crusher will prove a popular choice in wide range of small crushing jobs, and is committed to using programmable logic modules on subsequent new projects.

Indeed, Drew reports that the company has been so impressed with the Logo that the controller was one of the first components written into the specification for the design of a brand new light tower.