'Revolutionary' DIN rail signal conditioning units

The Medacs 2000 series from Status Instruments represents a totally new and revolutionary concept in DIN rail signal conditioning modules, offering a high degree of functionality and configurability

The Medacs 2000 series from Status Instruments represents a totally new and revolutionary concept in DIN rail signal conditioning modules, offering a high degree of functionality and configurability, together with the capability of interfacing to a wide range of industrial sensors.

The units, which are the result of three years extensive R and D, can be integrated directly into higher level plant control systems via bus systems, DCSs and the fast growing OPC software platform.

Medacs (Modular Expandable Data Acquisition and Control Systems) is aimed at specifiers of electronic equipment in large processing plants, system integrators and specialist panel builders.

As expected, the design of the Medacs modules meets Status's stringent criteria for performance and reliability, emphasised by the three way opto isolation and innovative electronics packaging.

Each unit has a RS485 serial communications link, enabling data to be sent to and from a host using Modbus protocol.

An ingenious 'bus jumper' system allows units to be easily bussed together, removing the need for complicated and expensive back plane wiring and speeding up the installation process.

Interfacing with other proprietary bus systems such as Ethernet, Profibus and others can be readily achieved via standard gateway modules.

In order to increase the flexibility of the Medacs modules, Status have pioneered the development of their Transfer Function Module Library (TFML), which is embedded in each unit.

Outputs include an isolated 4-20 mA re-transmission signal, a single change-over trip relay and dual normally open relays.

Units can handle standard mV, mA, temperature and frequency inputs and have, in addition, two isolated discrete digital inputs that can be used as to provide a reset function or any other function via TFML.

For high density systems, cost effective dual channel versions are available, while for systems that require more local input, single channel units,featuring a built-in key pad and digital display allow the user to access critical functions.

As Brian Turner, MD of Status, explains: " A conventional signal conditioner connects to a sensor and measures the sensor parameter, converting this to an industry standard output such as 4-20 mA.

TFML offers the capability of inserting a transfer function between the input and output to provide a special control function.

This gives customers the ability to configure the units to accommodate unusual or custom applications directly within the signal conditioning module.

We can write macros for customers or provide them with all the tools and training to write their own.

We are building up a library of macros and 'ones we did earlier' such as PID control, tank contents linearisation, signal accumulators and standard root functions can be downloaded free of charge from our web site".

Status have achieved full OPC compliance for the MEDACS series ensuring international compatibility and connectivity.

OPC (Object Linking and Embedding for Process Control) is a rapidly growing industry standard software platform developed through the collaboration of leading world wide automation and software manufacturers in conjunction with Microsoft -targeted with the simple goal of ensuring full Plug and Play for equipment.

The organization that manages this standard is the OPC Foundation.

The Foundation has over 270 members from around the world, including nearly all of the world's major providers of control systems, instrumentation and process control systems.

Based on Microsoft's OLE (now ActiveX), COM (component object model) and DCOM (distributed component object model) technologies, OPC consists of a standard set of interfaces, properties, and methods for use in process-control and manufacturing-automation applications.

The Active X/COM technologies define how individual software components can interact and share data.

OPC provides a common interface for communicating with diverse process-control devices, regardless of the controlling software or devices in the process.

By using the standard OPC client -server model, any OPC compliant device such as the Medacs units will connect easily and seamlessly into overall plant control systems, without the need for lengthy installation procedures and special interfaces.

OPC can be seen as a software abstraction layer and reduces the number of interface options that are needed to ensure connectivity.

To complete the impressive array of special features, the Medacs units have been certified as Associated Safe Area Equipment in accordance with the CENELEC/ATEX directive.

This option incorporates a certified zener barrier within the unit allowing it to be panel or wall mounted in the safe area with an intrinsically safe output loop to power suitable field mounted devices in the hazardous area.

The need for further zener barriers is therefore negated.

As Brian Turner concludes: " Signal conditioners are often viewed by our competitors as simple devices not worthy of significant development.

We firmly believe that we offer our customers distinct benefits by incorporating modern input/output features within the modules that keep pace with the rapidly changing technology in process control The trend towards full and flexible system integration, without the need for special software or interfaces, is expanding tremendously.

We intend to stay in the forefront of this technology and are confident of our claim that these new units really are 'Future Proof '".

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