CTM extends reach with Mitsubishi data logging

07 September 2010

A small British company has bolstered its overseas business with a PLC from Mitsubishi Electric. CTM Equipment in Barnsley specialises in machines for mixing polyeurethane foam, elastomer and epoxy resins.

The company exports its systems all round the world and supports the machines throughout their working lives. Its datalogging project started when a client in the offshore industry needed help with mixing very exact recipes to ensure the mechanical properties of insulating foam.

Engineer Chris Sykes, who lead the development project at CTM, explained: “Our client makes pipe lagging, but not of your common or garden variety. It’s all bespoke stuff for very demanding applications. They make insulating jackets for pipework on offshore production platforms. An exact mould of each length of pipe is taken and used to cast a made to measure jacket that covers all the bends, flanges, joints and valves.

“For the jacket to work properly it must expand and contract with temperature at exactly the same rate as its host pipework. This is achieved by individually blending each polyurethane mixture to an exact recipe.

“Our control system maintains process accuracy to within one per cent, and the datalogging function stores every parameter of every mix. We can also interrogate it in real-time from here in glorious Yorkshire without having to fly off to site. Of course it also has other functions such as safety and report preparation.”

Originally Sykes thought he would have to use a SCADA (supervisory control and data acquisition) system to achieve all of the required functionality. He was worried that the PC at the heart of such a system would not be robust enough for the journey to site or for use in the developing nations where many CTM machines operate.

However a conversation with Mitsubishi Electric’s Jeremy Shinton shifted the concept to the use of a single high performance PLC (programmable logic controller).

“We could achieve the desired functionality with a Q03 PLC,” said Shinton. “This unit has dual CPUs and twin racks onto which specialist modules fit to define a bespoke system for any application. And, of course, PLCs are totally deterministic so completely reliable in all circumstances.”

The key module for CTM was the datalogger, which is connected via Profibus to several drives flowmeters, temperature gauges and pressure monitors so that it is constantly collecting and storing all process data.

The PLC also connects to an Ethernet hub and onto two Mitsubishi E-series HMIs (human–machine interfaces), one at the mixing head, the other 20m away at the casting station. Operators standing at either of the two workstations can monitor – and to some extent control – the machine’s operation.
Ethernet is also used to connect the datalogger with a GPRS so that it can access the mobile phone network and communicate with CTM engineers back in Barnsley.

“A few years ago, we were spending a small fortune sending engineers around the world: one week it was Amsterdam, the next it was Nigeria,” explained Sykes. “Now the machines are just a phone call away, so our blokes can be working in Amsterdam one minute and Nigeria the next.”

This real-time communication is further enhanced by the fact that the Q03 PLC is internet enabled, so can be interrogated and reset from literally 1000 miles away.

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