LOWE Engineering Ltd are analyser system specialists with a special interest in industrial data acquisition. Their flagship product, CEMData, is a comprehensive data acquisition and report generation package designed around the complex legislative requirements of continuous emissions monitoring (CEM). This highly configurable package takes signals from a wide variety of sources from the latest industrial equipment, to legacy hard-wired and serial devices.
With installations in major power plant, gas turbines, North Sea oil processing, pharmaceuticals, municipal waste and even animal carcass incineration, Lowe require highly dependable equipment at a competitive price. The Intergrated Polution Prevention Control regulations (iPPC) demand very high equipment availability, for example: an interruption in analytical data collection exceeding four hours can necessitate a plant shutdown.
Lowe have used the Moxa DE-211 in a number of critical installations, providing auxiliary high-specification serial ports to data acquisition PCs via a LAN. These rugged DIN-rail mounted devices present a solid serial interface which can be re-configured within seconds via DIP switches to act as RS232, RS422 or RS485 (2- or 4-wire) ports. The ports can be software-assigned to any PC on the network by means of a very user-friendly configuration program provided with the device.
A major upgrade of the emissions monitoring system at a large plant presented additional challenges, requiring the use of two Moxa NPort slaves, which proved to be an ideal choice for this application. The NPort slave has three main operating modes (TCP Client, UDP and Real COM), in Real COM mode, the device is not pre-assigned to a particular PC, but is addressable by any computer on the network. The dual-redundant data acquisition PCs do not, therefore require mechanical switching of the RS232 lines when the main PC is taken off-line - instead CEMData can detect the changeover condition and allow the standby PC to take control of the auxiliary ports.