Data concentrator takes in six channels

Edited by the Engineeringtalk editorial team Feb 10, 2003

The Sitewatch data concentrator is a device for collecting data from up to six separate serial paths.

The Sitewatch data concentrator is a device for collecting data from up to six separate serial paths - for example from PLCs or other control equipment, or from traditional analogue and digital inputs.

Data are combined into a single memory space for storing and forwarding at intervals to remote master stations - either 'on demand' or 'on event' - for monitoring large, geographically spread, telemetry networks.

As with conventional telemetry, a PSTN, fixed landline or radio link can be used to transmit data from the Sitewatch data concentrator to remote master stations.

However, the potential of the unit is considerably extended by an integral web server, which provides remote monitoring and parameterisation capabilities to users accessing the system from a web browser.

The Sitewatch data concentrator supports GSM, and GPRS (always on) wireless connection can be also employed for transmitting alarms and events information immediately to a designated central location.

The concept is ideal for applications where increased numbers of I/O need to be handled, because multiple telemetry RTUs (outstations) become uneconomical after about 64 I/O points.

At the data source - eg the PLC(s) - it is only necessary to provide a serial card in order to exchange data with the Sitewatch data concentrator, allowing multiple data streams to be combined into a single unit that is more cost-effective and, using modern technology, can offer significantly more functionality to a remote user.

The concept is an extension of a conventional telemetry RTU and was developed by Lee-Dickens in response to market demand from a gas transportation customer, for metering gas purchase and distribution systems as well as user uptake and leak detection monitoring.

EU regulations require that metering is undertaken accurately and that a maximum demand policy is implemented.

By providing different user accounts, various levels of security are built into the Sitewatch data concentrator web server pages, enabling differing user requirements to be met.

For instance, users from the gas supply company can monitor and control all working parameters, whilst at the Gas Company customers can view data but not modify parameters.

Different web pages can be created and pages can be downloaded from the Sitewatch data concentrator so the system is flexible enough to meet varying requirements, both from the customer's point of view and over time as those needs change.

Other applications seen for the system include water collection and distribution systems and tank farm monitoring.

Lee-Dickens says that any situation where conventional telemetry has traditionally been used can benefit from the Sitewatch data concentrator, especially where multiple installations have to be monitored or as equipment is extended.

The Sitewatch data concentrator is fitted with direct local I/O capacity for special requirements such as critical operating parameters, power supplies, PLC watchdog, intruder and fire detection systems.

Up to 24 digital inputs, four analogue inputs and four digital outputs are available for this purpose, considerably extending the usefulness of the system.

The Sitewatch data concentrator has a ruggedised housing that means it can be mounted in any environment.

A touch panel and LCD display mounted on the front of the unit provides local control and parameterisation.