Low cost process control flexibility with MEDACS

MEDACS signal conditioners offer a totally new concept in sensor and process monitoring, interfacing to a diverse range of industrial sensors, providing configured outputs or web-based remote access

Process industries are highly dependent on primary measuring sensors and associated conditioning electronics to provide accurate and reliable data from the processes.

However in some applications, straightforward control and measurement requirements are solved using over-engineered and expensive PLC solutions.

Recognising this situation, UK based Status Instruments have continued to develop their MEDACS range of DIN rail signal conditioning modules which provide a solution for many such applications.

These imaginative products offer a high degree of functionality and configurability, allowing them to be used to solve a growing number of process control applications in a very cost effective and expedient manner.

As Ian Pullin, Managing Director for Status Instruments explains: "MEDACS signal conditioners offer a totally new concept in front-end conditioning which can be used to interface to a diverse range of industrial sensors.

Conventional signal conditioners connect to a sensor and measure the sensor parameter, converting this to an industry standard output such as 4-20 mA.

However, MEDACS can take the sensor inputs and then modify them to provide outputs with special functionality.

The concept has been developed for a range of engineers including specifiers of electronic equipment in large processing plants, system integrators and specialist panel builders.

Status units can handle most common sensor inputs including mV, mA, temperature and frequency and, in addition, have two isolated discrete digital inputs.

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

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

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

For high density systems, cost effective dual channel versions are available".

WEB ACCESS.

In the drive for higher efficiencies and reduction in manpower, remote access to equipment is vital.

The MEDACS concept has now been expanded to incorporate an embedded web server, bringing almost limitless possibilities for these devices.

The web server gateway module allows access via a user-configurable interactive website.

Remote website access can be achieved via Ethernet, standard PSTN modem, GSM or ISDN.

Access to the critical parameters allows trouble shooting and system adjustments to be carried out remotely.

In many cases any problems can be resolved without the need for an engineer to visit the site - which may be on the other side of the world.

As an example, at remote oyster production plants in Northern France, MEDACS is being used to monitor critical temperature and humidity conditions.

Given the high value of the oysters, it is crucial that they are processed and stored under the right conditions.

The system is designed so that if the parameters go outside preset tolerances, a text message is sent to one of the service engineers.

Rather than have to rush off to the plant, the engineer can access the system through a laptop computer and check the status.

The system provides three decision levels depending on the severity of the problem.

For instance, at 'level one' the engineer may be able to reset the system and then put the problem right at the next scheduled visit.

At 'level two', the engineer may need to plan a visit within a short period of say two to three days, or at 'level three', it may be necessary to make an immediate visit.

Given the long distances involved, making a calculated decision based on accurate data can save considerably on costs without jeopardising the crop.

Ian Pullin is very upbeat about the future potential for MEDACS and as he concludes: "We believe its versatility is only limited by the imagination of our customers and we are seeing different control applications solved on a weekly basis.

MEDACS can be used in OEM equipment and standalone, one-off, applications: the concept is particularly useful when applied to existing installations and equipment".

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